open letter to NASA | Planetary protection issues abstract | main points in open letter in more depth | finding an inspiring future | executive summary of preprint | this is like asking an architect to install a smoke detector | NASA's legal requirements under NEPA | About me

Author: Robert Walker, contact email robert@robertinventor.com

Open letter to NASA: let’s keep Earth 100% safe and make this an even better mission when you return samples from Mars in the 2030s - do listen to planetary protection experts, and restore the interagency panel as the Space Studies Board advised

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[NOT YET SENT TO NASA - READY SOON]

Dear NASA planetary protection center of excellence (Planetary Protection) and other interested parties.

[Please forward to your point of contact for comments on the draft EIS]

I am following up on my public comments on your plan to return samples from Mars in the early 2030s after you requested comments as required by NEPA. The Council on Environmental Quality advises the public that if our concerns aren’t resolved during comments on the Environmental Impact Statement (EIS), we need to contact the agency:

Your first line of recourse should be with the individual that the agency has identified as being in charge of this particular process. (A citizen’s guide to the NEPA: Having your voice heard : 28)

[using a simple form of inline cites as a linked title to the paper, and page number etc]

I raised many issues in the first round of comments and these weren’t addressed in the second round, for a simple example I told you that the European Space Foundation Study in 2012 set requirements well beyond those of a BSL-4 with the need to contain ultramicrobacteria as well as the very small gene Transfer Agents in the sample handling facility. There is no mention of this issue in the section where you respond to the public comments or anywhere.

I emailed your point of contact Dr Alvin L,. Smith II on 18th December. I got no response (it might be my mistake, I see I forgot to add a subject line). I am trying again as recommended by the CEQ. I look forward very much to your reply.

Here is a video presentation of this open letter

Video: Open letter to NASA [First draft]

[Need to redo - I overstated the capabilities of HOTTech. LLSE is a probe not a rover. We can't yet make the equivalent of Perseverance or Curiosity able to function at 500°C for months on end - though given the pace of development we may be able to by the 2030s.]

[For sterilization we just need the tech to withstand 300°C for a few minutes for sterilization. A reasonable first challenge would be a 100% sterile Marscopter - and very useful]

[If you see any mistakes however large or small don't hesitate to let me know].

Titles of sections are like mini-abstracts - and hover mouse over left margin for floating menu

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The title of each section also summarizes its main conclusions similarly to an abstract. You can get a good first idea by just reading the titles of sections - and looking at any graphics.

Hover your mouse over the left margin of the page to see a floating menu of all the section titles. You can get a first overview by reading just the top level headings, shown in bold, similarly to an abstract. The second level of headers is like an extended abstract. Because it is easy to navigate this open letter I felt it might be appropriate to go into a bit more depth than would be usual in some of the sections, material that would more usually be in the supporting information.

I use hyperlinked inline citations in this open letter consisting of the title in brackets hyperlinked to the paper and then the page number after the title like this: (Mars Sample Return: Issues and Recommendations (1997) : 6 - 7)

NASA has been world leading in planetary protection - but since early this century it moved the other direction against the advice of the Space Studies Board

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NASA has been world-leading in protection of Mars from forward contamination – from any terrestrial life that might get there and proliferate in any habitats that might exist in the Martian desert landscape.

You have also been world-leading in your literature on a Mars sample return. I was so surprised at the mistakes I found in the EIS which I listed in my response on the last day of public comments which you have surely read by now (Comment posted December 20th).

However I understand better now. I found out you closed down your planetary protection office, which operated from 1997 to 2017 (With planetary protection office up for grabs, …), after first closing down the interagency panel in 2006 (Review and Assessment of Planetary Protection … : 26) which could have advised you, for instance on public health, and the planetary protection subcommittee in 2016.

Your current planetary protection engineer says your priority for planetary protection now is to prepare the way for humans to go to Mars as fast as possible, and you want other agencies to help support this goal (SMA Leadership Profile: Nick Benardini). He is now an employee in your Office of Safety and Mission Assurance, with no independence from NASA.

These public comments are the only method you have left to spot your numerous mistakes in the EIS - which arise because you no longer have anyone left in the team trained in risk assurance or planetary protection - this is the time when you most need peer review

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In this way NASA effectively shut down all external and internal critical peer review of your plans at a time when you most need it to guard against such mistakes. This is against the repeated advice of the Space Studies Board that you need such a panel such as: (Assessment of planetary protection requirements for Mars sample return missions : 67 - 68), and, most recently in 2018 saying you need to reestablish it and that it is needed for peer review (amongst other reasons):

Finding: The development and implementation of planetary protection policy at NASA has benefited in the past from a formally constituted independent advisory process and body. As this report is written, both the advisory body and process are in a state of suspension.

Recommendation 3.6: NASA should reestablish an independent and appropriate advisory body and process to help guide formulation and implementation of planetary protection adequate to serve the best interests of the public, the NASA program, and the variety of new entrants that may become active

The roles of the advisory body include the following:

[other roles] …

Act as a peer review forum to facilitate the effectiveness of NASA’s planetary protection activities.

(Review and Assessment of Planetary Protection … : 61 - 62)

This wasn’t done.

This leaves public comments like mine as the only remaining way to find mistakes. We have these public comments only because you are legally required under NEPA to request these comments

My aim is to help make this an even better mission - and we now have the technological capability to achieve 100% planetary protection for Earth - and for Mars too

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My focus here is to chart a way forward for NASA to recover from these mistakes and retain its leading role in planetary protection and to do a mission with enhanced science return and safe for Earth. As I said in the conclusion to my comment:

Let's make this an even better mission and SAFE for Earth.

(Comment posted December 20th)

I’ve done some extra videos for sections of this open letter for those who prefer video presentations - and which sometimes go into more depth.

Video: Open letter to NASA: 100% protection

Since I did that public comment, I’ve been working on a preprint and literature survey to look at this in more depth, based on a paper I was already working on, on planetary protection for your sample return mission before you started on the EIS process. The preprint is here:

As I outlined in those 14 points, we now have the ability to achieve 100% planetary protection both ways.

So - that’s at least one positive direction we can go in the future. I expand on those suggestions towards the end of this open letter and in far more detail in the preprint.

We are at decision point for our civilization - not just NASA - with two ways we can go - no planetary protection in the near future - or 100% planetary protection both ways in the near future

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However it is very important to get this first step right, the EIS and the first samples from Mars

We need to establish a good precedent for the future. We have the option to set a precedent of

Understandably Mars enthusiasts think it makes colonization easier to drop all planetary protection - but most of the world won’t be convinced enough by hunches to authorize spaceships returning from Mars potentially carrying Martian life

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However, if Mars colonization enthusiasts are correct that we will find no life on Mars, or only life that can mix with Earth’s biosphere with no harm in either direction, it is far better for their objective if we don’t drop planetary protection quite yet.

If we put 100% planetary protection in place right now, we enhance science return. We will be able to send rovers to Mars without the noise of contamination by terrestrial life, and return clean samples that we can study again with no terrestrial contamination in our miniature telerobotic facility.

With clean missions to Mars and clean samples returned from Mars, we get a far clearer picture of what’s on Mars far faster

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In this way we get a far clearer picture of what we have on Mars far faster which means we can answer the questions that Mars colonization enthusiasts should want answers to too. They rely at present on hunches and vivid metaphors to persuade others that what they want to do is safe for Earth’s biosphere. If they are right they will be able to use scence instead.

Also with 100% clean rovers we can send numerous miniature robotic explorers everywhere on Mars - with gigapixel cameras and the broadband communications back to Earth which NASA is planning to install this decade - which will be amazing assets for the Mars colonizers if that is what we do eventually.

This mission plan can’t survive in its current form to 2033 - far better to work on it in your own time than in response to legal challenges or a presidential directive - or worse - in response to an emergency bill in Congress in the early 2030s

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Also, as we’ll see, there is no way this mission plan can survive as it is all the way through to 2033.

I will suggest it is best for NASA to change direction now. and work on things in your own time, rather than later in response to either legal challenges - or the presidential directive - or worst case of all, some emergency bill in Congress to say you have to sterilize the samples before they can contact Earth’s biosphere, when they are already on their way back in 2033.

Experts all say - we can't do a classical probabilty estimate - but in their expert opinion the risk is likely low - of large-scale harm to human health or our biosphere - Margaret Race uses the analogy of a smoke detector for a house fire - a low risk but a risk of high significance - we do need smoke detectorsa

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Margaret Race, a biologist working on planetary protection and Mars sample return for the SETI Institute and specialist in environmental impact analysis used the analogy of a smoke detector in response to similar non-peer-reviewed suggestions by the space colonization enthusiast and leader of the Mars Society Robert Zubrin:

If he were an architect, would he suggest designing buildings without smoke detectors or fire extinguishers?

Hazardous Until Proven Otherwise, in (Opinion: No Threat? No Way : 5)

Hand installing smoke detector labelled “NASA” and wooden ceiling of a house labelled “Earth”

(Smoke detector graphic from The EnergySmart Academy)

I am a long term admirer of NASA - and I’m doing all this just to get you to install a working smoke detector

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I am doing all this to get NASA to install a smoke detector but one that I think is exceptionally important despite the low risk, because Earth’s biosphere is a “house” with billions of people in it.

I have been a long term admirer of NASA. You have done so much and are doing so much by way of advancing science and space exploration, robotic and human. Most of our discoveries about Mars are the result of observations by NASA missions.

Carl Sagan: “we cannot take even a small risk with a billion lives”

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Carl Sagan is one of my heroes and I have the same focus as him in this respect. Enthusiastic about space science. Keen on space exploration, including both robotic and human exploration. Watched the Apollo landings in amazement in the 1960s. Marvelled at the Voyager “grand tour” of the solar system. But I also greatly value Earth’s biosphere and its inhabitants.

For me, the value of Earth and its inhabitants is essentially infinite.

Text on graphic: Carl Sagan (pioneer in planetary protection - first paper in 1960)
[his first paper is (Biological contamination of the Moon)]

“I, myself, would love to be involved in the first manned expedition to Mars. But an exhaustive program of unmanned biological exploration of Mars is necessary first.

“The likelihood that such pathogens exist is probably small, but we cannot take even a small risk with a billion lives.”

[quote from: (The Cosmic Connection – an Extraterrestrial Perspective)]
[I provide text captions for the graphics in this open latter for visually impaired readers]

In this EIS, I saw a box that looks like a smoke detector but without batteries and not up to the latest specs

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In this analogy, I didn’t see a functioning smoke detector in this Environmental Impact Statement. I saw a box that looks like a smoke detector but doesn’t really function, doesn’t match modern design requirements for a smoke detector and has no batteries installed. We have to fix that.

This mission plan will not succeed without broad acceptance by the general public as well as the many scientists who do not belong to NASA

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This is how John Rummel, NASA’s first planetary protection officer, put it in 2002:

“Broad acceptance at both lay public and scientific levels is essential to the overall success of this research effort.”

(A draft test protocol for detecting possible biohazards in Martian samples returned to Earth: 99)

There will be intense public scrutiny of NASA’s plans as it gets nearer to the date the samples return to Earth. If you still don’t have a functioning smoke detector in this analogy you will have to fix this.

The obvious last minute fix is a bill in Congress in the early 2030s requiring you to sterilize all samples before they reach Earth - and with no on board sterilizer your spacecraft would have to fly past Earth and you retrieve the samples later for sterilization.

I am writing this to help you find a better solution.

Carl Sagan's strong focus on protecting humans and Earth's biosphere as our top priority is not unusual - out of those who commented - 50 out of 63 would likely agree with Sagan and nine specifically mentioned unprecedented harm as their concern

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Carl Sagan’s strong focus on protecting Earth is not an unusual concern in the general public. Several dozen distinct members of the public expressed views on your EIS that suggest they would be in support of a similar approach to planetary protection that places a very high value on Earth’s biosphere.

Nine commentators specifically mention unprecedented harm and 50 out of 63 made comments that make it clear they would agree with Sagan’s view.

50 out of 63 shouldn’t be read as a percentage of the public as it is not a poll. But it does show that at least several dozen of the members of the public who were reached in the not very well publicized second round of comments had concerns similar to Sagan.

These are links to all the comments. Many are short and succint but clear in what they intend to say. The ones that would surely agree with Sagan are highlighted in bold.

Those are 56 comments so far that would agree with Sagan.

Four more comments were very detailed with attachments making the same point.

Thomas Dehel quoting from an interview he did with Gill Levin, principle investigator for the first and only direct life detection experiment sent to Mars, who died shortly before the start of the EIS process

"I believe people will realize, especially after the Covid-19 catastrophe, that even if there’s only a small chance that something could be contagious and pathogenic, coming from a foreign planet, I don’t think it’s worth taking that chance….you don’t take unnecessary chances where the risk-to-benefit ratio is almost infinite.”

. Comment posted December 13th

Barry DiGregario quoted from an interview he did with Carl Woese when he was alive. Carl Woese is the biologist who used gene sequencing to identify the archaea, the third realm of life. As the botanist Otto Kandler put it: “He opened a door which nobody expected to exist” (The singular quest for a universal tree of life).

“When the entire biosphere hangs in the balance, it is adventuristic to the extreme to bring Martian life here. Sure, there is a chance it would do no harm; but that is not the point. Unless you can rule out the chance that it might do harm, you should not embark on such a course”

. Comment posted December 5th

Chester Everline, co-author of your handbook on probabilistic risk assurance (Probabilistic risk assessment procedures guide for NASA managers and practitioners) found that the EIS didn’t state clearly what level of risk NASA is prepared to take for Earth’s biosphere. This is the same issue we mentioned in the last section, where NASA were not prepared to give an answer to the question:

Just how low is “low likelihood”? Is NASA’s goal specification to prevent accidental release of the Mars samples 1 in a thousand? 1 in a million? 1 in a billion?

(MSR DRAFT EIS 3–3),

The background here is that when asked by a member of the public - what risk are they prepared to take - 1 in 1000, 1 in 1 million, 1 in 1 billion etc - NASA just said

No outcome in science and engineering processes can be predicted with 100% certainty.

[then deflect away from the question] The safety case for MSR safety is based on ...

(MSR DRAFT EIS 3–3),

Chester Everline said:

A possible consequence of unsuccessful containment is an ecological catastrophe. Although such an occurrence is unlikely, NASA should at least be clear regarding what level of risk it is willing to assume (for the biosphere of the entire planet)

...

A better statement of options should include the possibility of delaying the return of Mars samples until the risks associated with their return are better understood

(Comment posted December 20th)

He doesn't mention, but we can also sterilize all samples returned to Earth as in my suggestion. Both of these can be predicted to keep Earth safe with 100% accuracy.

My own final comment, in 14 points ending:

Let's make this an even better mission and SAFE for Earth.

. Comment posted December 20th

For potentially scared people: Margaret Race’s analogy of a smoke alarm puts it very well - the level of risk is likely similar to the risk of a house fire - very low - but high significance so we do have to install a working and up to date smoke detector

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I help scared people over the internet, and since this is an open letter, before I go any further, it is very important to me to explain clearly early on that the risk is likely low and especially for this mission See:

The errors I found (which I'm about to describe) are neophyte errors - your former planetary protection officers would have been incapable of such mistakes

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Your former planetary protection officers are world leaders in the field of planetary protection and they would never have let such mistakes through. I’d never expect a NASA EIS to have such mistakes.

Video: Open letter to NASA: your mistakes

These are systemic errors due to having nobody on the team trained in planetary protection or risk assurance - and not the fault of any individual scientist or engineer - Space Studies Board finds it always has to educate committee members unfamiliar with basic planetary protection concepts

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It’s important to recognize these mistakes are not the fault of any authors of the EIS. The Space Studies Board say they need to educate committee members unfamiliar with basic planetary protection concepts.

“ … with additional time being required to educate those committee members unfamiliar with basic planetary protection concepts.”

(Review and Assessment of Planetary Protection Policy Development Processes : 77)

They are clear and major mistakes..

One basic mistake runs through the entire Environmental Impact Statement - for risk assurance you need to look at worst case scenarios - the EIS ends the analysis at best case scenarios

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One basic mistake pervades the report - the EIS looks at best case scenarios for planetary protection throughout. But we need to look for worst case scenarios, as with the analogy of a smoke detector.

Microbes from Jezero crater do NOT get to Earth better protected and faster in Mars meteorites - a sample tube is like a miniature spaceship for a microbe

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Let’s look at an example right away.

“The natural delivery of Mars materials can provide better protection and faster transit than the current MSR mission concept … First, potential Mars microbes would be expected to survive ejection forces and pressure (National Academies of Sciences, …, 2019), …” (MSR DRAFT EIS 3–3),

This is saying, falsely, that any life returned from Mars in your sample tubes can get here with better protection and faster in a meteorite from Mars.

Although many in the space community think this meteorite argument has been established, it is

The National Research Council (NRC) sample return study in 2009 said it is not appropriate to use this argument for Martian samples (Assessment of planetary protection requirements for Mars sample return missions : 48).

Most species of terrestrial microbe die when suddenly accelerated from rest to faster than a hypervelocity bullet - and most of those that survive die of dehydration in a vacuum

Most terrestrial microbes couldn’t survive the sudden acceleration to ejection at many times the speed of a hypervelocity bullet and couldn’t survive the cold and vacuum of space (Natural transfer of viable microbes in space: 1. From Mars to Earth and Earth to Mars : 392)..

Surface dust, dirt, and salts can’t physically become a meteorite - your own cite makes this point - and also says that microbes may not be able to survive ejection or transport through space

The surface dust, dirt and salts in Jezero crater couldn’t get here at all. Even your own cite in the EIS, though valid for samples from Phobos, says it shouldn’t be used for samples from the Mars surface. It briefly explains why the argument is invalid. This is from your 2019 cite for “potential Mars microbes would be expected to survive ejection forces and pressure “:

“The sample may well come from an environment that mechanically cannot become a Mars meteorite. The microbes may not be able to survive impact ejection and transport through space.”

(Planetary protection classification of sample return missions from the Martian moons : 45)

This already shows the argument is invalid. However this reasoning is so strongly believed by many space enthusiasts that I feel it is necessary to go into more detail.

(MORE DETAILS - BECAUSE MANY BELIEVE THIS PLAUSIBLE BUT INVALID ARGUMENT) our martian meteorites all come from at least 3 meters below the surface - modeling suggests at least 50 meters - many microbes that live in rocks need access to sunlight - also most of the martian subsurface is very uninhabitable - uniform -73°C at a depth of 12 centimeters or deeper except at geothermal hot spots if any

Also the most recent meteorites arriving from Mars today came from the Zunil crater impact somewhere around 700,000 years ago by direct crater count (Do young martian ray craters have ages consistent with the crater count system? : 626) .

This is from rocks from at least 3 meters below the surface (another source says at least 5 meters) by the low levels of radioisotopes produced by cosmic radiation (Ejection ages from krypton‐81‐krypton‐83 dating and pre‐atmospheric sizes of Martian meteorites : 1355). Impact modeling may suggest a depth of 50 to 100 meters below the surface (Ages and geologic histories of Martian meteorites : 152). There’s other confirmatory evidence that they come from at least 1 meter below the surface (The role of target strength on the ejection of martian meteorites : 3) because they don’t show any sign of ionizing radiation from the sky on one side of the rock.

Anywhere below 12 centimetres has a uniform temperature of around -73°C   (Adsorption water-related potential chemical and biological processes in the upper Martian surface. : figure 2)

There may be present day life in caves warmed by the heat from geothermal processes but so far no such hotspots are known - if they exist they are likely rare and rarely sampled by meteorite impacts . There may be life deep below the surface, at a depth of kilometers in the hydrosphere. But immediately below the surface is very uninhabitable for life. There is evidence of hydrothermal processes such as steam explosions in the rootless cones less than 20 million years old (Interactions between Athabasca Valles Flood Lavas and the Medusae Fossae Formation (Mars): Implications for Lava Emplacement Mechanisms and the Triggering of Steam Explosions). It's pllausible that Mars may have subsurface hydrothermal processes today that life can use, but so far no current hotspots are known.

We might find life if we drill but we’ll need to know where to look - in most places we’d need to drill kilometers to find warm rock.

In a scenario with present day life in the surface dirt of Jezero crater, there may be many species that couldn’t get into rocks meters below the surface even in hydrotherml systems. Microbes that can live inside rocks are called endoliths. Many terrestrial microbes can't live in rocks. Of those that can, many need to live near the surface of the rock with access to sunlight.

We will see that there are many proposed microhabitats native martina life could inhabit that don't require access to geothermal heat.

The best case scenario for planetary protection is a microbe like b. subtilis - which if it exists on Mars may get here on rare occasions (not proven and was a great surprise at the turn of the century when we found it might be possible)

The best case scenario for planetary protection here is for microbes like b. subtilis that may be able to transfer from Mars to Earth (The Interplanetary Exchange of Photosynthesis : 5) (page 5 of the manuscript).. But what matters for invasive species are the ones that can’t get here. For instance most photosynthetic life can’t survive impact shock (The Interplanetary Exchange of Photosynthesis).. Mileikowsky et al., authors of a seminal paper on modern lithopanspermia (transfer of microbes between planets inside rocks), say most microorganisms known wouldn’t be able to travel through space: (Natural transfer of viable microbes in space: 1. From Mars to Earth and Earth to Mars : 392)

However we should look at worst case scenarios for planetary protection - analogy of barn swallows which were already in the Americas - it's the starlings that couldn't cross the Atlantic that cause $1 billion of agricultural damage a year

The example of starlings and barn swallows may help. Barn swallows are like b. subtilis which can cross between planets - because it can fly across the Atlantic. But what matters for planetary protection are the worst case scenarios like starlings that can’t get here.

Starling damage reported to the USDA’s Wildlife Services program averages less than $2 million per year, but this is a fraction of all starling damage. Agricultural damage alone is estimated currently at $1 billion per year. Other damage, such as costs for cleaning and maintaining city centers near roosts, veterinary care and loss of production at CAFOs, and public health care, are unknown. A complete inventory of all economic damage likely would show that the starling is the most economically harmful bird species in the United States

(European Starling : 16).

Text on graphic: Some microbes may be able to get from Mars to Earth – what matters for invasive species are the ones that can’t.

Barn swallow - can cross Atlantic

Starling - invasive species in the Americas

Didymosphenia geminatum invasive diatom in Great Lakes and New Zealand, can’t even cross oceans

We need to be prepared to find unfamiliar life on Mars with no common ancestor with terrestrial life - astrobiologists often say this when they design instruments to search for life on Mars, and NASA's own iMost team agrees

Astrobiologists say we need to be prepared to find unfamiliar life on Mars that has no common ancestor with terrestrial life. That includes the iMOST team you assembled to advise you on the science experiments for the samples from Jezero crater.

“We cannot predict with any accuracy life's form and characteristics, whether it would be viable …, or whether it shares a common ancestor with life on Earth.”

(iMOST : 88)

Text on graphic: Zunil crater and Jezero crater marked.

The last meteorites to leave Mars for Earth

  • left Zunil crater 700,000 years ago (approx)
  • came from at least 3 meters below the surface
  • probably from at least 50 meters below

In scenarios with present day Martian life:

  • most species in Jezero crater probably can't reach Zunil crater (perhaps biofilms in ultracold brines or in micropores in gypsum)
  • most terrestrial microbes can't survive sudden ejection at kms / sec or vacuum
  • the surface dust, salts and dirt can't physically become a meteorite
  • most species in surface layers probably can't get into deep rocks (eg. photosynthetic)

We don’t know if ANY LIFE EVER GOT FROM MARS TO EARTH

Background map: Google Mars doesn't seem to have an option to share this exact scene - but this is a zoom in on Jezero crater in Google Mars and Zunil crater in Google Mars

In short, this is a widely held belief, that any Martian species have got to Earth already. However, as we see, it's not a valid argument.

Your former planetary protection officers would have been incapable of making this error.

No we don't have evidence Mars is uninhabitable - you even plan to test Perseverance's samples to see if any lifeforms detected from Mars are stil alive

Also it is incorrect to say we have evidence Mars is uninhabitable (Mars Sample Return DRAFT EIS : 1–6).

Existing credible evidence suggests that conditions on Mars have not been amenable to supporting life as we know it for millions of years (… National Research Council 2022).
(Mars Sample Return DRAFT EIS : 1–6)

The second half of your Goal 1 for Mars exploration is to search for present day life (Mars science goals, objectives, investigations, and priorities: 2020 version : 9).

It is also objective 2.3 for your samples you plan to return from Jezero crater:

Your scientists plan to

Your own cite for “existing credible evidence" that Mars is uninhabitable is actually about searches to see if "habitable regions currently exist " on Mars

Even your own cite for “existing credible evidence” is the opposite of evidence, it reads: “The exploration of … Mars … will help establish whether localised habitable regions currently exist within these seemingly uninhabitable world”. (Origins, Worlds, and Life : 393 [Click on the X to go straight to page 393]).

The reader isn’t alerted to these discrepancies.

The biological safety report similarly looks only at best cases for planetary protection - a systemic issue - needs someone on the team trained to search carefully for worst case scenarios as they miss several counterexamples that aren't hard to find

Before I mention issues with the Biological safety report, I'd like to thank the sterilization working group for the effort formulating their position in a scientifically precise way with example diseases. Some of the counterexamples were often subtle and in some cases they led my survey to topics that seem new to the planetary protection literature. As an example - following up their example of Candidas lead to the counterexample of Aspergillus which I mention below. They also raised the issue of prions for the first time since 1997 and there are various other points of interest in the report.

The issues I found in the biological safety report were more of a systemic nature. They were rather to do with their overall approach to risk assurance, of looking for best case scenarios and then looking no further once they found them, which showed a lack of training in risk assurance and is a side effect of NASA's decisions to close down its planetary protection office and other sources of peer review that would have spotted the mistakes. .

Though the counterexamples were often sublte and hard to spot, there were several counterexamples in the literature that they could have found relatively easily if anyone had searched for them. It's more an issue with the approach. To add to the remark of your first planetary protection officer, John Rummel:

People have to have some kind of respect for the unknown. If you have that respect, then you can do a credible job, and the public is well-served by your caution.”

(Controversy Grows Over whether Mars Samples Endanger Earth)

I think it's also to do with asking the right question. To serve the public well you need to ask the question:

"Let's see if there is any way this house CAN have a house fire even though the risk seems low".

In worst case senarios microbes do NOT need to have long-term evolutionary contact with Earth hosts to harm us - example of tetanus which kills thousands of unvaccinated newborns every year and legionnaires disease which is a disease of protozoa and biofilms not adapted to invade lungs which also kills

“Since any putative Martian microorganism would not have experienced long-term evolutionary contact with humans (or other Earth host), the presence of a direct pathogen on Mars is likely to have a near-zero probability.” (Biological safety : 6)

Your biological safety group focuses on best case scenarios for planetary protection of diseases adapted to humans, even considering diseases like yellow fever transmitted to humans from monkeys via mosquitoes (Biological safety: 6).

The report shows no awareness of counter examples in the literature like tetanus (Tetanus), which kills thousands of unvaccinated newborns a year and is not adapted to infect any organism, and Legionnaires disease, only adapted to infect protozoa and also able to live outside protozoa in a biofilm, and many others in the report by Warmflash et al. (Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions, 14–15)

Warmflash et al. were discussing the potential for astronauts on Mars to be harmed by extant microbes there. They concluded that we should accept these risks because in their view they are outweighed by the benefits of human exploration of Mars. They suggeste we contain them as far as possible, through biological .containment on Mars and quarantine on return to Earth., writing:

Since the discovery and study of Martian life can have long-term benefits for humanity, the risk that Martian life might include pathogens should not be an obstacle to human exploration.

. (Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions, 2)

My suggestion in this open letter is that with modern technology we no longer need tto balance the value of human colonization of Mars or a Mars sample return against low risks of possibliy widespread harm to human health.

However the Biolgically safety report sidesteps the whole discussion - the report shows no awareness that there is any posssibility of harm of this type.

In worst case senarios microbes that live in extreme conditions on Mars would be pre-adapted to warm conditions on Earth - example of a microbe from the Canadian permafrost isolated at -16°C, may be able to grow below -25°C, with optimal growth at 25 C and able to grow up to human blood temperature

The biological safety report focuses on best case scenarios for planetary protection of microbes that live only in extreme conditions on Earth reasoning:

“There are many described extremophiles that may survive in environments that are extreme to human or animal life (e.g. extremes of temperature or pressure) but do not survive under conditions in our normal habitat (Merino et al. 2019) … Thus, it is plausible that any Martian microbe, after it arrives on Earth, would not be viable on Earth due to a lack of its required Martian nutritional and environmental conditions.” (Biological safety: 6)

This shows no awareness of many examples of terrestrial microbes that do well in Mars simulation chambers, which suggests the same is possible in reverse

Their only cite, Merino et al, has a counterexample Planococcus Halocryophilus: (Living at the extremes: extremophiles and the limits of life in a planetary context: table 3) Optimal growth at 25°C and up to 37°C. Showed metabolic activity down to -25°C, the lowest temperature tested ((Bacterial growth at− 15 C …) and may grow at ultra low temperatures too slowly to test in the laboratory). isolated from Canadian permafrost with ambient temperature around -16°C . (Bacterial growth at− 15 C; molecular insights from the permafrost bacterium Planococcus halocryophilus Or1)

Text on graphic: Merino et al.'s table of extremophiles has one remarkable exception with a very broad temperature range

Optimal growth 25°C. Metabolic activity at least to -25°C. Found at -16°C.

(Living at the extremes: extremophiles and the limits of life in a planetary context.: table 3)

These four plausible but invalid arguments reinforce false beliefs in the space community - which they use in good faith to recommend dropping all planetary protection for Mars and Earth

These arguments reinforce false beliefs in the space community. They are already used, in good faith but incorrectly, to recommend dropping all planetary protection for samples from Mars, for instance by Robert Zubrin, president of the Mars society (Contamination From Mars: No Threat) with the response from planetary protection experts (Opinion: No Threat? No Way : 4 - 7)

These are Zubrin's four plausible but invalid reasons for dropping all planetary protection. They are affirmed and not countered in this EIS: I summarize briefly why they are in valid in square brackets, briefly summarized the detailed explanations presented in the previous sections..

These are extremely serious mistakes because of the high regard NASA enjoys for planetary protection due to its previous excellence in the field - if this EIS is not withdrawn by NASA, other actors in good faith but mistakenly could use just one of those arguments to drop all planetary protection both ways for missions to Mars

I can’t overstress how extremely serious these mistakes are, because of the precedent and respect for NASA and its previous reputation in the field of planetary protection. Everyone looks to NASA for the lead on planetary protection.

If just one of those arguments was indeed valid, we could drop all planetary protection of Earth. This EIS is a potential precedent for other actors, in good faith, to return samples from anywhere on Mars with no protection of Earth’s biosphere.

Draft EIS uses a controversial cite for its statement that Jezero crater is too hostile for life - SR-SAG2 - they don't mention that both NASA and ESA took the unusual step of commissioning a review of this study out of concerns that the authors were too closely aligned with the Mars Program office

The draft EIS says the Martian surface is too inhospitable for life to survive in Jezero crater, where Perseverance is collecting samples ( NASA, 2022 : 1-6):

Consensus opinion within the astrobiology scientific community supports a conclusion that the Martian surface is too inhospitable for life to survive there today, particularly at the location and shallow depth (6.4 centimeters [2.5 inches]) being sampled by the Perseverance rover in Jezero Crater, which was chosen as the sampling area because it could have had the right conditions to support life in the ancient past, billions of years ago (Rummel et al. 2014, Grant et al. 2018).

[Rummel et al., 2014 is often referred to as SR-SAG2]

Their cite Grant et al seems to be a mistake. It’s about the geographic features of the landing site. It briefly mentions in one sentence that Vastitas Borealis was rejected partly for planetary protection reasons because of subsurface ice. That's it.

For the first cite, first, it has no discussion of potential capabilities of Martian life. Also, by referring only to SR-SAG2, NASA’s EIS misses out the Space Studies Board review (Review of the MEPAG report on Mars special regions) which modified all the main conclusions that NASA relies on for this statement about Jezero crater.

NASA and ESA commissioned this review of SR-SAG2 partly out of concerns that MEPAG is not independent from NASA. When they found out that they had similar concerns they commissioned a combined revew.

There were two reasons why both agencies took the seemingly unusual step of independently commissioning reviews of a review paper that was to be published in a peer-reviewed journal.

First, there is the perception in some circles that MEPAG is not independent and that its views are too closely aligned with NASA’s Mars Program Office.

( Review of the MEPAG report on Mars special regions. : xi – xii).

This is an understandable omission as the critical review by the Space Studies Board has only 16 cites in Google scholar and SR-SAG2 has 308 cites - but it is serious as the SSB review found many knowledge gaps in SR-SAG2 - your first two planetary protection officers could never have made this mistake

SR-SAG2 seems to be better known than this review of it. SR-SAG2 has 308 cites in Google Scholar. The Space Studies Board review of it has only 16 cites in Google scholar.

This is an understandable omission - but it is serious omission from an Envirionmental Impact Statement given that NASA and ESA comissioned the report because of a perception in some circles that the views of the MEPAG group were too closely aligned to the Mars Pprogram office ( Review of the MEPAG report on Mars special regions. : xi – xii).

Again this is a mistake your first two planeatary protection officers would have been incapable of making.

Many of the knowledge gaps identified in the Space Studies Board review of SR-SAG2 are highly significant for Jezero crater

I will go into this in some depth because the SR-SAG2 picture is so widely cited and the Space Studies Board review isn't so well known. It paints a picture of a potentially far more habitable Mars especially when combined with new discoveries since 2015 about potential new microhabitas, biofilms and transport ithrough the atmosphere amongst others.

- that maps made from orbit represent an incomplete state of knowledge about habitability and are subject to change

The Review of MEPAG warns that maps such as the ones NASA relied on to select Jezero crater as a landing site represent an incomplete state of knowledge

Maps that illustrate the distribution of specific relevant landforms or other surface features can only represent the current (and incomplete) state of knowledge for a specific time—knowledge that will certainly be subject to change or be updated as new information is obtained

( Review of the MEPAG report on Mars special regions. : :28):

- that SR-SAG2 didn't adequately discuss transport in the atmosphere

 The Space Studies Board Review of MEPAG also says SR-SAG2 didn’t adequately discuss the potential for life to be transported in the dust in the atmosphere (e.g. dust storms)

"The SR-SAG2 report does not adequately discuss the transport of material in the martian atmosphere. The issue is especially worthy of consideration because if survival is possible during atmospheric transport, the designation of Special Regions becomes more difficult, or even irrelevant."

( Review of the MEPAG report on Mars special regions. :12).

 Here, “special regions” are regions where terrestrial organisms are likely to propagate. The second half of the definition isn’t used much given that we don’t yet know capabilities of any putative Martian life:

“within which terrestrial organisms are likely to propagate, or a region which is interpreted to have a high potential for the existence of extant martian life forms.”

( Review of the MEPAG report on Mars special regions. ::6)

If terrestrial life can be spread from anywhere to anywhere on Mars it becomes much harder or impossible to map out safe regions for forward contamination, depending how easily it can spread

- that SR-SAG2 only briefly considered implications of lack of knowledge of microenvironments - it gave a list of seven potential types of microenvironment that may occur o the surface of Mars but then took this no further

The Space Studies Board review of MEPAG says SR-SAG2 only briefly considered the implications of our lack of knowledge of microenvironments on Mars

Physical and chemical conditions in microenvironments can be substantially different from those of larger scales. Although the SR-SAG2 report considered the microenvironment (Finding 3-10), the implications of the lack of knowledge about microscale conditions was only briefly considered.

( Review of the MEPAG report on Mars special regions. :12).

This is what the 2014 report said (Rummel et al. , 2014:904).

Finding 3-10: Determining the continuity/heterogeneity of microscale conditions over time and space is a major challenge to interpreting when and where Special Regions occur on Mars.

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

It then gives a list of seven naturally occurring microenvironments on Mars: Vapor-phase water available Vapor or aerosols in planet’s atmosphere; within soil cavities, porous rocks, etc.; within or beneath spacecraft or spacecraft debris

  • Ice-related Liquid or vapor-phase water coming off frost, solid ice, regolith or subsurface ice crystals, glaciers
  • Brine-related Liquid water in deliquescing salts, in channels within ice, on the surface of ice, within salt crystals within halite or other types of ‘‘rock salt’’
  • Aqueous films on rock or soil grains Liquid water on regolith particles of their components such as clay minerals, on surface of ice, on and within rocks, on surfaces of spacecraft
  • Groundwater and thermal springs (macroenvironments) Liquid water
  • Places receiving periodic condensation or dew Liquid water on regolith particles of their components such as clay minerals, on surface of ice, on and within rocks, on surfaces of spacecraft
  • Water in minerals Liquid water bound to minerals

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

The 2015 Space Studies Board review says that though SR-SAG2 considered these microenvironments it only briefly considered the implications of our lack of knowledge of them

Physical and chemical conditions in microenvironments can be substantially different from those of larger scales. Although the SR-SAG2 report considered the microenvironment (Finding 3-10), the implications of the lack of knowledge about microscale conditions was only briefly considered.

…

Craters, and even microenvironments underneath and on the underside of rocks, could potentially provide favorable conditions for the establishment of life on Mars, potentially leading to the recognition of Special Regions where landscape-scale temperature and humidity conditions would not enable it.

…

The review committee agrees with Finding 3-10 of the SR-SAG2 report but stresses the significance of the microenvironment and the role it might play on the definition of a Special Region in areas that (macroscopically speaking) would not be considered as such.

(Review of the MEPAG report on Mars special regions : 11 - 12 ).

- example of the brines found by Curiosity

(Transient liquid water and water activity at Gale crater on Mars.figure 3a and 3 c), An example of the SR-SAG2

“Brine-related Liquid water in deliquescing salts, in channels within ice, on the surface of ice, within salt crystals within halite or other types of ‘rock salt’”

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

Biiofilms might make them habitable, so I'll discuss this in the section on biofilms belwo.

- example of water condensing in micropores in salts found in the Atacama desert that may be relevant to Mars

Cassie Conley mentioned one of them:

From the perspective of planetary protection, Conley is also concerned about terrestrial organisms that can absorb water from the air. She recalls fieldwork she did in the Atacama Desert in Chile, which is one of the driest places on Earth, with less than 0.04 inch of rain a year.

Even in this dessicated place, she found life: photosynthetic bacteria that had made a home in tiny chambers within halite salt crystals. There’s a small amount of water retained inside the halite and, at night, it cools down and condenses both on the walls of the chambers and on the surface of the organisms that are sitting there.

(Going to Mars Could Mess Up the Hunt for Alien Life)

These are an example of the SR-SAG2

Vapor-phase water available Vapor or aerosols in planet’s atmosphere; within soil cavities, porous rocks, etc.; within or beneath spacecraft or spacecraft debris

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

Jezero crater doesn't have the massive white salt deposits of Gale crater but it has gypsum, in small quantities at least. So it could have life using micropores in gypsum. This increases the humidity of the air significantly and water condenses inside the pores.

There is a fair bit of research now into these micropore habitats, including gypsum and salt. The first paper is from 2010: ( Novel water source for endolithic life in the hyperarid core of the Atacama Desert) just one year after the most recent NRC Mars sample return report in 2009. Other papers include alt. ( Microbial colonization of halite from the hyper-arid Atacama Desert studied by Raman spectroscopy, 2012 ) and Paul Davies wrote an opinion piece about them in the Guardian in 2014( The key to life on Mars may well be found in Chile)

This is of especial importance for Martian life as it would have had millions of years to discover and colonize microhabitats such as pores in salt or gypsum, or melting frost layers, or to adapt to retain water from the brines discovered by curiosity, or to make use of the humidity in the atmosphere.

The Space Studies Review of SR-SAG2 draws special attention to biofilms which are able to modify conditions to make them ore habitable, in effect building a microbial "house" using plastic like substances that they exude to portect themselves

The Space Studies Board review draws special attention to biofilms. These aren’t discussed in SR-SAG2 (it has only one mention of the word).

Given the wide distribution and advantages that communities of organisms have when they live as biofilms enmeshed in copious amounts of EPS [substances that microbes can produce around them to help make a “home” in a hostile environment], it is likely that any microbial stowaways that could survive the trip to Mars would need to develop biofilms to be able to establish themselves in clement microenvironments in Special Regions so that they could grow and replicate.

(Review of the MEPAG report on Mars special regions :11)

The 2015 Space Studies Board review starts the biofilm section saying:(Review of the MEPAG report on Mars special regions :11).

The SR-SAG2 report identified the ability of microorganisms to withstand multiple stressors as an important area of research..

How EPS (extrapolymeric substances) can make a “home” of the hostile Martian surface.

The SR-SAG2 report identified the ability of microorganisms to withstand multiple stressors as an important area of research..

Text on graphic: How EPS (extrapolymeric substances) can make a “home” of the hostile Martian surface. Some of the environment stressors 100% humidity varies to 0% Heat, cold, UV, dust storms Oxidants, nutrients Algae may add oxygen Retains moisture from night to daytime when temperature soars from -70°C to above 0°C. Cryoprotectants - protects from cold shock Extrapolymeric substances (EPS): proteins, DNA, lipids, polysaccharides, other large organic molecules. A biofilm is like a microbe's house which can keep it warm, wet, protected from UV, and which it shares with other microbes

Text on graphic: How EPS (extrapolymeric substances) can make a “home” of the hostile Martian surface.

100% humidity varies to 0%

Heat, cold, UV, dust storms

Oxidants, nutrients

Algae may add oxygen

Retains moisture from night to daytime when temperature soars from -70°C to above 0°C.

Cryoprotectants - protects from cold shock

Extrapolymeric substances (EPS): proteins, DNA, lipids, polysaccharides, other large organic molecules.

A biofilm is like a microbe's "house" which can keep it warm, wet, protected from UV, and which it shares with other microbes

Graphic adapted from figure 2 of (Stream biofilm responses to flow intermittency: from cells to ecosystems)

Microbes in biofilms can use those extrapolymetric substances (EPS) to inhabit ecological niches that would otherwise be uninhabitable (Review of the MEPAG report on Mars special regions :11)

The majority of known microbial communities on Earth are able to produce EPS, and the protection provided by this matrix enlarges their physical and chemical limits for metabolic processes and replication. EPS also enhances their tolerance to simultaneously occurring multiple stressors and enables the occupation of otherwise uninhabitable ecological niches in the microscale and macroscale.

Illustrative scenario suggested by Mosca et al combining three of these ideas and relevant to Jezero crater - biofilms that formed in the past on Mars when it was more habitable and propagated ever since as fragments blown in the winds on Mars perhaps only succeeding occasionally in establishing a foothold in a new microenvironment

Combining these ideas we get an especially interesting scenario for Jezero crater which combines together three of those knowledge gaps, transport in the atmosphere, biofilms and microhabitats. Amongst several relevant discoveries, later research found small fragments of biofilm, thin layers of a microbial colony three hundredths of a millimeter thick, can travel 100 kilometers in daylight in the light Martian winds before it is sterilized (A desert cyanobacterium under simulated Mars-like conditions in low Earth orbit: implications for the habitability of Mars)

(An Overview of Biofilm Formation–Combating Strategies and Mechanisms of Action of Antibiofilm Agents : Figure 1)

Mosca et al. suggest that a biofilm could still propagate on Mars in this way as complete biofilm fragments, even if local conditions don’t permit it to establish a biofilm today by slowly growing from a few microbes. All that is needed is that at some time in the past biofilms were able to form, propagating ever since then using these broken off fragments 2019. (Over-expression of UV-damage DNA repair genes and ribonucleic acid persistence contribute to the resilience of dried biofilms of the desert cyanobacetrium Chroococcidiopsis exposed to Mars-like UV flux and long-term desiccation

As for how biofilms could make microenvironments in Jezero crater habitable for themselves, one idea is Nilton Rennó's suggestion that a biofilm could make the Curiosity brines habitable. Curiosity found liquid water in the salts that take up water at night - on the surface through to 6 am on the same day that it measured surface brines for the last time in the year, it registered a midday temperature of 15 °C (Transient liquid water and water activity at Gale crater on Mars.figure 3a and 3 c) Those brines are habitable but too cold for terrestrial life at -73°C at 6 am on that day. But could life somehow retain that water through to warmer conditions?

These brines are an example of the SR-SAG2

“Brine-related Liquid water in deliquescing salts, in channels within ice, on the surface of ice, within salt crystals within halite or other types of ‘rock salt’”

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

Nilton Rennó is an expert on Mars surface conditions, who was part of the team that discovered the Phoenix lander drops, principle investigator for Phoenix and who also runs the REMS weather station on Mars for Curiosity. He is co-author of a major review of the current evidence for water and brines on Mars ((Water and brines on Mars: current evidence and implications for MSL)

, suggested in an interview that microbes might use biofilms to inhabit these brines

"Life as we know it needs liquid water to survive. While the new study interprets Curiosity's results to show that microorganisms from Earth would not be able to survive and replicate in the subsurface of Mars, Rennó sees the findings as inconclusive. He points to biofilms—colonies of tiny organisms that can make their own microenvironment.

(“Mars liquid water: Curiosity confirms favorable conditions”)

Persverance can't detect these brines as it doesn't have Curiosity's Dynamic Albedo of Neutrons (DAN) instrument (DAN for Scientists), but calculations suggest they would also be found in Jezero crater; and last longer before drying out than they do in Gale crater (Global Temporal and Geographic Stability of Brines on Present-day Mars : Figure 7). Also as with Gale Crater, the ground temperature in Jezero crater often varies from well below -70 °C to well above 15 °C in a single day as measured by Perseverance (Diurnal variation of the surface temperature of Mars with the Emirates Mars Mission: A comparison with Curiosity and Perseverance rover measurements : Figure 3).

These would likely be a mix of many species working together for extra resilience like the grit crust in the Atacama desert (The grit crust: A poly-extremotolerant microbial community from the Atacama Desert as a model for astrobiology)

In the preprint I try to flesh out one way this could happen by combining this with recent research that finds that terrestrial mosses may be good Mars analogue organisms - could Mars have moss like organisms that absorb water fast in the early morning when Curiosity found ultra cold salty water even on the surface at -73°C - and retain it even through to midday on the same day when temperatures reached over 15°C? See Executive summary highlights .

Researchers have proposed many more habitats.I mention a few in the highlights of the executive summary below, see Executive summary highlights .

A common misconception about perchlorates - some microbes are harmed by perchlorates but for others they make Mars more habitable - a giant dinner plate in the words of Cassie Conley, NASA's second planetary protection officer

This is a common misconception about Mars - that the perchlorates make it uninhabitable. It's the opposite. For some microbes yes, they make it less habitable but for others they make Mars MORE habitable.

Cassie Conley put it like this in 2015.

The salts known as perchlorates that lower the freezing temperature of water at the R.S.L.s, keeping it liquid, can be consumed by some Earth microbes. “The environment on Mars potentially is basically one giant dinner plate for Earth organisms,” Dr. Conley said.
(Mars Is Pretty Clean. Her Job at NASA Is to Keep It That Way)

There are many reports of perchlorate reducing microbes from perchlorate contaminated soils. However they also occur naturally in some places that are naturally enriched in perchlorates (Evidence for Biotic Perchlorate Reduction in Naturally Perchlorate-Rich Sediments of Pilot Valley Basin, Utah)

The view that perchlorates make Mars uninhabitable to microbes is much more widespread than the view that it makes it more habitable. It's a case of which microbes. For some microbes it makes it less habitable, for others it makes it more habitable and you can expect native Martian life to be adapted to it. Biofilms can also help microbes be more resilient to perchlorates and other factors.

If there is life on Mars, either the native Martian life actually uses it, or it is very resistant to oxidants which it has to be anyway with perchlorates and a very oxidising surface. Interestingly the microbe from the Canadian permafrost that the Biological Safety Report missed is actually able to grow in 10% by weight perchlorate solution.

Furthermore, our results show the development of cohesive biofilms in perchlorate-rich media (Fig. 4A)

(Bacterial Growth in Chloride and Perchlorate Brines: Halotolerances and Salt Stress Responses of Planococcus halocryophilus)

The 3-day conference in 2019 "Extant Life on Mars - What's Next?" mentions only one sample return of special interest as a habitat for present day life - surface salts including perchlorates

The report of the 3 day conference on the potential for present day life on Mars, held in Carbland New Mexico on November 5-8 mentions only one specific suggestion for a Mars sample returrn to look for present day life. It suggests that salts are a prime target both for their preservation potential for recent life and as a habitat for present day life. It specificaly mentions perchlorates as a potential habitat.

If life exists today on Mars, or existed in the recent past, microscopic examination of such evaporite minerals and their fluid inclusions might offer a straightforward and realistic way to confirm its existence, while spectroscopic analyses may uncover biochemicals that represent biosynthetic or breakdown products of life.

Moreover, having these features as potential targets for future Mars Sample Return efforts would allow for potentially concentrated organics and extant life analyses within its mineral structure.

Salts and brines containing concentrated dissolved solutes and gas pockets could serve as energy and nutrient resources for life (e.g., perchlorates, nitrates, sulfates, organics, methane), with near-surface evaporites additionally providing access to sunlight for potential phototrophic activities.

Consequently, when considering NASA’s current mission concepts, evaporitic environments at the surface and near subsurface offer targets that are likely to be readily accessible to robotic exploration.

( Mars Extant Life: What's Next? Conference Report : 797) ( html)

Yes perchlorates are bacteriocidal for b. subtilis when irradiated with UV - but the effects are far less at lower temperatures or when mixed with dirt or dust - a shadow under a rock or a few microns of dirt eliminates most of the UV as do dust storms - and the organic plastic compounds exuded by biofilms (EPS) and other modifiers would protect microobes against oxidants like chlorates, and chlorites, or indeed hydrogen peroxide

One experiment on the effect of UV on perchlorates in the dirt often gets mentioned but it's results were inconclusive and doesn't count against perchlorates as a habitat for native Martian life. They only tested one species, b. subtilis. They only tested it at 25 C and 4 C when the effect was much less:

The chemical nature of this bacteriocidal effect is confirmed by carrying out the experiment at 4 °C, when the loss of viability is over ten times lower than at 25 °C, suggesting that lower temperatures lower the rate of the chemical reaction or the diffusion of activation products and reduce the rate of bacteriocidal effects. Nevertheless, the effect is still observable. The average surface temperature on Mars is approximately 218 K (−55 °C), however the Mars Exploration Rover Opportunity measured a daily maximum of 295 K (21.85 °C) Therefore, we would expect a range of reaction rates varying with latitude and time of day.

- typical temperatures on Mars are below 0 C when perchlorates are far less active. The experimenters didn't test UV irradiated perchlorates with polyextremophiles that might be more resilient;.. Native life is likely to be more resilient to oxidants than terrestrial extremophiles.

They also found it was reduced by mixing the microbes with rock. But this is the normal scenario on Mars:

The effect is less pronounced within the rock analogue system likely caused by screening within the rock, which reduces the penetration of UV radiation compared to the liquid system.

A few microns of dust are enough to block UV completely. Then finally, biofilms screen out UV and would also protect microbes against oxidants.

The rock analogue system consisted of:

sintered discs of silica grains commercially produced to give a pore size of 100–160 µm

Billi et al found that their fragment of a biofilm could survive for 8 hours of daylight traveling 100 km - not tested with perchlorates but biofilms can protect microbes from oxidants. ( . Dried biofilms of desert strains of Chroococcidiopsis survived prolonged exposure to space and Mars-like conditions in low Earth orbit. : 8-9) Billi et al. suggest

… Our findings support the hypothesis that opportunistic colonization of protected niches on Mars, such as in fissures, cracks, and microcaves in rocks or soil, could have enabled life to remain viable while being transported to a new habitat

( A desert cyanobacterium under simulated Mars-like conditions in low Earth orbit: implications for the habitability of Mars)

Also, dust storms would reduce UV reducing this effect and increase the survival times for individual microbes. Curiosity was able to give direct observations of surface UV during the 2018 global dust storm, and found that it fell by 97% at the start of this storm, and remained at similar low levels for about three weeks (solar longitude 195 to 205)

Chart, scatter chart Description automatically generated

UV measurements by upward pointing photodiodes on the REMS instrument suite on Curiosity. The UV fell by 97% at the onset of the dust storm ( . The Mars Global Dust Storm of 2018) : Figure 5)

Even during the dust storms, the wind speeds continue at night at 3-4 meters per second increasing to 10 meters per second or more in the day time – at least as measured from the Insight lander for the dust storm in 2019. Before the dust storms, the night wind speeds were above 5 meters per second for most of the night, increasing to a maximum of around 10 meters per second just before dawn at around 4 am. So there seems significant potential for transport of biofilms for large distances at night.

Blue dots show the wind speeds 5 days before the 2019 dust storm as measured from the Insight lander site, about 5 meters per second at night, increasing to 10 meters per second in the middle of the day.

Red dots show the wind speeds 5 days after onset which range from around 3 meters per second most of the night to above 10 meters per second in the middle of the day.

(Effects of a large dust storm in the near ‐surface atmosphere as measured by InSight in Elysium Planitia, Mars: figure 5).

So during the dust storms there would be little by way of UV in daytime and none at night. Biofilms could travel a long way in the storms traveling day and night for several weeks. This could extend Billi et al.'s 100 km to 1000s of kilometerse.

This suggests a sceanrio where martian biofilms hop from one microhabitat to another a few tens of kilometers at a time, maybe even hundreds to thousands of kilometers on rare occasions, similarly to the way desert nomads use oases to cross deserts.

If so Perseverance might detect life that is in process of hopping from one oasis to another even if it hasn't found the oases themselves (unlikely without in situ life detection).

ALL of the currently confirmed or uncertain novel microenvironments found on Mars relevant to native Martian life were surprises - and there are many other suggestions we can't currently test - and couldn't see from orbit

Focusing our attention just on the confirmed microenvironments, it turns out ALL were surprises, NONE of them were predicted [Will add cites]:

We do have many testable predictions - here are some of them. None of these suggested microenvironments could be seen from orbit:

Some are relevant to Jezero crater. Others would need subsurface ice or other processes thta are not possible in Jezero crater but may be within range for viable life transported in the Martian dust storms on occasion.

I cover some of these in the Executive summary, see See Executive summary highlights - and cover all of them in more depth in the preprint.

Then add to that, ALL the microenvironments found so far were surprises. So, in addition to the possibility of confirming some of those proposed microenvironments, we seem likely to get more surprises that nobody has yet proposed.

Then given that biofilms could be transported via the atmospehre, Jezero crater isn't far from more habitable regions that could be a source for them

It is far too soon to close the book on micro-environments on Mars or even in Jezero crater. It's understandable that the iMost team are keen to suggest that we look for present day life in the returned samples from Jezero crater. (iMOST : 91 t - 93).

However - if these habitats exist, then they are likely to be rare. There may be microbial oases for life on Mars tens or hundreds of meters apart or even further apart, like oases in terrestrial deserts. Mars could have oases kilometers apart in Jezero crater and microbes may hop from one to another rarely every few hundred thousand years like nomads traveling from one oasis to another in a desrt.

Or there may be viable life in the dust but even the distant habitats on Mars, if they exist, may have only small amounts of life. Even a few thousand microbes per gram would be detectablle at a distance of thousands of kilometers if large areas of Mars are habitable. We detect microbes from the We can detect life from the Gobi and Taklimakan Deserts in dust in Japan (Aeolian dispersal of bacteria associated with desert dust and anthropogenic particles over continental and oceanic surfaces) (will come back to this below). However, any microbes from distant parts of Mars may be diluted to a few microbes per gram or less once the dust reaches Jezero crater. So, without in situ life detection, Perseverance will only return this life by chance.

That is, unless the Viking experiments did find life in the 1970s. If the labelled release did find life it may be almost everywhere even in the lower latitudes explored by Perseverance, possibly in the dust or dirt and if so Perseverance might have a higher chance of returning life. Or indeed if there was life there but the Viking experiments didn't detect it. The iMost team refer to that possibility.

As we see, the picture presented in the Space Studies Board review of SR-SAG2 is a potentially far more habitable Mars than the picture presented in SR-SAG2 and research since then has found many ways that life on Mars could be possible within the knowledge gaps that the Space Studies Board review identified. However most of the Mars research community uses SR-SAG2 rather than the Space Studies Board review.

After many plausible but invalid arguments your EIS reaches the judgement "potential environmental impacts would not be signfiicant"

Not surprisingly after many plausible seeming but invalid arguments, your EIS says:

The relatively low probability of an inadvertent reentry combined with the assessment that samples are unlikely to pose a risk of significant ecological impact or other significant harmful effects support the judgement that the potential environmental impacts would not be significant.

ALL major studies to date say there is a risk of large-scale effects - experts do believe the risk to be low - but HIGHLY SIGNIFICANT

ALL the major studies for a Mars sample return are in agreement, there is a risk of large-scale effects though it is believed by experts to be low . This runs through the planetary protection literature from the beginnings of the discipline, in the late 1950s to 60s, with Joshua Lederberg, Carl Sagan and others, onwards (When Biospheres Collide : 35, 420)

The most recent European Space Foundation (ESF) Mars sample return study in 2012 concurs with the 2009 Mars sample review and indeed all the major sample return studies to date:

The Study Group also concurs with another conclusion from the NRC reports (1997, 2009) that the potential for large-scale effects on the Earth’s biosphere by a returned Mars life form appears to be low, but is not demonstrably zero.

(Mars Sample Return backward contamination–Strategic advice and requirements : 20)

In more detail they say:

… it is not possible to estimate a probability that the sample could be harmful or harmless in the classical frequency definition of probability.

However it is possible to establish the risk as low, as a consensus of the beliefs of the experts in the field as represented by their experience.

(Mars Sample Return backward contamination–Strategic advice and requirements : 24)

2012 ESF study says Mars samples should be treated like the most hazardous Earth organisms we know about until we know more (risk group 4) and your former planetary protection officer Cassie Conley says the same in one of your official NASA videos

The 2012 ESF study goes on to say Mars samples should be treated like risk group 4 organisms (high individual and community risk, highly infectious, no treatment available) until we know more. I.e. we should treat them as significant.(Mars Sample Return backward contamination–Strategic advice and requirements : 24)

Cassie Conley, former NASA planetary protection officer from 2006 - 2018 summarized it like this:

“that means we are going to contain the samples as if they were the most hazardous Earth organisms that we know about, Ebola virus.”

at 1:02 into this official NASA video

Your first planetary protection officer, John Rummel says people have to have some kind of respect for the unknown

John Rummel, NASA planetary protection officer from 1997 to 2006, as interviewed by Scientific American in 2022 after the first round of public comments on your proposals summarized it like this:

We keep finding Earth organisms doing new things that are quite interesting from the standpoint of potential life elsewhere. So why don’t we think we need to be careful? The answer is that we do need to be careful, as repeatedly emphasized by the National [Academies]....

People have to have some kind of respect for the unknown. If you have that respect, then you can do a credible job, and the public is well-served by your caution.”

(Controversy Grows Over whether Mars Samples Endanger Earth)

General picture from ALL studies back to the Apollo era - it appears to be low risk but need respect for the unknown - low risk is highly significant

That’s the general picture here from ALL the major reports ever commissioned on the topic back to the Apollo era as we saw (Mars Sample Return backward contamination–Strategic advice and requirements : 20) (When Biospheres Collide : 35, 420)

It appears to be a low risk but we need a respect for the unknown, and as a result this low risk is highly significant.

Even a low risk of large-scale effects must be considered carefully and thoroughly. I don’t see that in this EIS. There is no mention of the conclusion of previous studies that we have to contain the samples as if they were the most hazardous Earth organisms known.

With this statement that the environmental effects would not be significant NASA achieves a major legal simplification - e.g. no need to consider impacts on the Great Lakes, or oceans, or invasive species and minimal need to involve other agencies - not suggesting for a moment that this is the motivation but it's the effect of it

Video: Open letter to NASA: legal effects of these serious errors and how they lead to a mission that as planned is likely to be of no interest to astrobiology.

By saying that environmental effects would not be signfiicant, NASA can skip various presidential directives to consider:

and many others (NASA Facilities Design Guide)

Then they also

Then with the new fast track NEPA process they can complete it all in a year, giving much less time for others to notice and challenge their plans. Before the NEPA modernization, the average time was 4.5 years and something like this would have likely taken longer.

CEQ found that over the past decade, the average time for agencies to complete an EIS was 4.5 years. CEQ’s current guidance suggests that this process, even for complex projects, should not take more than one year. (NEPA Modernization)

If instead the EIS says there is a low risk of large-scale effects - this also has international implications after the EIS is completed

The sample receiving facility would be in the USA with the current plans - but ESA member states are involved in returning the samples from Mars to the USA, so they also are involved. Directive 2001/42/EC would likely apply Directive 2001/42/EC of the European Parliament and of the Council of 27 June 2001 on the assessment of the effects of certain plans and programmes on the environment). This is similar to NEPA, including the need for a draft report, public comments and so on. This is an example of how it is implemented in the UK, which still retains the law though no longer in the EU. (Strategic Environmental Assessment Directive: guidance - Practical guidance on applying European Directive 2001/42/EC)

Also the UK and many other member states of ESA are parties to the Espoo convention (Environmental Assessment - Espoo Convention). Under that convention they need to consult with each other on all major projects that can have an effect outside of their own boundaries - which would certainly apply to a Mars sample return release of life that transformed the biosphere.

Then, though the USA is not part of the Convention on Biological Diversity, all the participating nations of ESA are, indeed all UN nations except the USA which leads to obligations to prevent introduction of alien species that threaten ecosystems, habitats or species:

"Each Contracting Party shall, as far as possible and as appropriate:

...(h) Prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species."

Convention on Biological Diversity, 1997, Legal text

There are many other relevant conventions and treaties and once the US says there is potential for large scale effects, it would likely involve:

No matter which country is involved in planning a Mars sample return mission, at some stage, international agencies like the Food and Agriculture Organization may get involved, because of potential impact on agriculture and fisheries and global food supplies, and the World Health Organization because of effects on human health globally if a new organism is returned that can be spread to other countries.

They might not have much by way of authority but they would affect public opinion in the USA.

There are many international implications. See: (Updating Planetary Protection Considerations and Policies for Mars Sample Return) and (Planetary Protection, Legal Ambiguity, and the Decision Making Process for Mars Sample Return)

This is not suggesting in any way that NASA's motivation was to simplify the international legal situation. But it is an effect of this statement.

All these precautions are there for a reason. We need to be especially careful about a decision that can potentially lead to bypassing all these precautions that protect Earth's biosphere.

NASA plan to use many basic principles of a Biosavety Level 4 facility to contain the samples - this is based on the science of 1999 but is now out of date for a Mars sample return

NASA plan to contain the samples using many of the basic principles of a Biosafety level 4 facility (BSL-4) facility - based on the science of 1999

This is what NASA say:

Nevertheless, out of an abundance of caution and in accordance with NASA policy and regulations, … NASA and its partners would use many of the basic principles that Biosafety Level 4 (BSL-4) laboratories use today to contain, handle, and study materials that are known or suspected to be hazardous.

(MSR DRAFT EIS S-4),

The science of 1999 did set requirements achievable by a BSL-4 – that the probability that a single particle of 0.2 microns or larger is released into Earth’s environment is less than 1 in a million (Mars Sample Return backward contamination–Strategic advice and requirements : 3).

The European Space Foundation in 2012 said we have to contain the far smaller ultramicrobacteria and gene transfer agents - 100% containment at 0.05 microns or larger and 1 in a million for release of a single particle ever at 0.01 microns or larger

The European space foundation said we have to contain ultramicrobacteria and gene transfer agents - well beyond the capabilities of a BSL-4 - based on the science of 2012

The ESF in 2012 updated this 1999 requirement to 1 in a million containment for a single particle of 0.01 microns or larger, and 100% containment for 0.05 microns or larger (Mars Sample Return backward contamination–Strategic advice and requirements : 48).

Screenshots from (Mars Sample Return backward contamination–Strategic advice and requirements : 21). and (Mars Sample Return backward contamination–Strategic advice and requirements : 48).

Their recommendation of 100% containment at 0.05 microns was the result of reviewing reports that ultramicrobacteria are still viable after passing through a 0.1 micron nanopore (Mars Sample Return backward contamination–Strategic advice and requirements : 15). They cited two studies, in freshwater from Greenland (Detection and isolation of ultrasmall microorganisms from a 120,000-year-old Greenland glacier ice core) and 20 different sites in Switzerland (Quantification of the filterability of freshwater bacteria through 0.45, 0.22, and 0.1 μm pore size filters and shape-dependent enrichment of filterable bacterial communities).

This has been confirmed many times since then.

Text on graphic: Size limit 1999 to 2012: 0.2 microns

ESF Size limit (2012): 0.05 microns

The European Space Foundation study in 2012 reduced the limit from 0.2 microns to 0.05 microns after the discovery that these ultramicrobacteria are viable after passing through 0.1 micron nanopores

Next size limits review might reconsider ribocells – theoretical size limit 0.01 microns

Background graphic: SEM of a bacterium that passed through a 100 nm filter (0.1 microns), larger white bar is 200 nm in length (Passage and community changes of filterable bacteria during microfiltration of a surface water supply)

Their 1 in a million containment at 0.01 microns or larger is because of a discovery that the even smaller Gene Transfer Agents can transfer genes and so, genetic capabilities such as antibiotic resistance to the genomes of distantly related microbes (archaea) in sea water far more rapidly than previously thought, overnight (Mars Sample Return backward contamination–Strategic advice and requirements : 19) citing (High frequency of horizontal gene transfer in the oceans) (summarized in (Virus-like particles speed bacterial evolution))

I alerted you to this issue that a BSL-4 can’t meet the requirements of the ESF study in the first round of public comments

This 100% containment at 0.05 microns is well beyond capabilities of BSL4 facilities. Even ULPA level 17 filters only contain 99.999995 percent of particles tested only to 0.12 microns (BS, 2009:4).

...

An experimental 6-layer charged nanofiber filter intended for coronaviruses filters out 88% of ambient aerosol particles at 0.05 microns (Leung et al, 2020).

Even this would not achieve 100% containment.

… (Comment posted on May 16th by Robert Walker to NASA’s first request for comments on their plans)

We don't need to contain ultramicrobacteria in terrestrial labs or gene transfer agents - and nobody seems to be working on filters to do this - but ultramicrobacteria could bring novel life and gene transfer agents could bring novel genetic capabilities to Earth for related life

Nobody seems to be working on the technology to contain ultramicrobacteria or GTAs - we don’t normally need to do this. Modern reviews of air filter technology don’t mention any attempts to achieve such capabilities (Application of Electrospun Nonwoven Fibers in Air Filters).

Ultramicrobacteria could bring novel life (such as mirror life or other exotic biology) to Earth from another biosphere and if Martian life is related to terrestrial life, gene transfer agents could bring novel capabilities to terrestrial microbes that Martian life evolved in the very different conditions on Mars.

The ESF says we need to do a new review of the size limit and level of assurance regularly - definitely needed a decade later - so even their limit is now out of date

Also before developing any such technology we need a review of the size limits and level of assurance - the ESF in 2012 said we need to do this regularly

Based on our current knowledge and techniques (especially genomics), one can assume that if the expected minimum size for viruses, GTAs or free-living microorganisms decreases in the future, and this is indeed possible, it will be at a slower pace than over the past 15 years.

However, no one can disregard the possibility that future discoveries of new agents, entities and mechanisms may shatter our current understanding on minimum size for biological entities. As a consequence, it is recommended that the size requirement as presented above is reviewed and reconsidered on a regular basis

(Mars Sample Return backward contamination–Strategic advice and requirements : 21)

RECOMMENDATION 8: Considering that (i) scientific knowledge as well as risk perception can evolve at a rapid pace over the time, and (ii) from design to curation, an MSR mission will last more than a decade, the ESF-ESSC Study Group recommends that values on level of assurance and maximum size of released particle are re-evaluated on a regular basis

(Mars Sample Return backward contamination–Strategic advice and requirements : 48)

A decade later this review is needed first before we can design any air incinerators or filters to the new standard.

A new size limit review could look at recent research into the very tiny ribocells

The next size limit review may examine new research into extremely small early life cells such as ribocells with enzymes made from fragments of RNA instead of proteins (Maintenance of Genetic Information in the First Ribocell). Steven Benner and Paul Davies say the small 0.01 micron diameter structures in the martian meteorite ALH84001 are consistent with RNA world cells (Towards a Theory of Life : 37).

Panel 4 for the 1999 workshop estimated that one of the structures in the Mars meteorite ALH84001 was consistent with a minimum volume early life RNA world cell 14 nm in diameter and 120 nanometers in length, if there is an efficient mechanism for packing its RNA (Size limits of very small microorganisms: proceedings of a workshop : 117). New research into ribocells might lead to a review panel to reconsider this suggestion.

A new size limit review could look at prions - raised by the biosafety laboratory and not considered before since 1997

The next size limit review might also need to look at prions. This a new issue raised by the Biological safety report (Biological safety: 6) that was previously mentioned in the 1997 report but not considered since then (Assessment of planetary protection requirements for Mars sample return missions : 60). The 1997 report said:

Subcellular disease agents, such as viruses and prions, are biologically part of their host organisms, and an extraterrestrial source of such agents is extremely unlikely.

(Mars Sample Return: Issues and Recommendations : 21)

Biological safety report said most likely Martian prions are harmless to Earth organisms - but that we need to be able to sterilize them - so which is it?

The Biological safety report argues in the same way that most likely Martian prions are harmless to Earth organisms, unless the terrestrial host was similar to Martian hosts and they argue that Earth is unlikely to have similar hosts (Biological safety: 4). However they also recommend that samples are sterilized sufficiently to inactivate prions before they are released (Biological safety: 16). If it is indeed necessary to sterilize proteins to make samples safe for distribution, it may be necessary to contain prions.

So which is it, do we need to contain prions or not? There is a new factor here not considered in previous reports. We now know that microbes get prion diseases too.

We now know that yeasts, bacteria and arcahea all get prions - so the last universal common ancestor may well have had prions - and a protein from the bacteria that causes botulism can act as a prion in the unrelated bacteria e. coli

Yeasts often get prions and indeed most of them are beneficial (How do yeast cells contend with prions?.: table 1) but two of them are harmful and yeasts protect against them with various mechanisms (How do yeast cells contend with prions?: figure 2). These are all ones that arise spontaneously in yeast cells. We might find yeasts on Mars especially if it has related life. Some fungi especially black yeasts do well in Mars simulation experiments (BIOMEX experiment: ultrastructural alterations, molecular damage and survival of the fungus Cryomyces antarcticus after the experiment verification tests).

Then, in a discovery from 2017, bacteria such as e. coli can get prions too and in this case a protein Rho from an unrelated bacteria Clostridium botulinum, the microbe that causes botulism, can act as an inheritable prion that changes the functionality of E. coli. They found two such fragments, the shortest of them, a fragment of Rho only 68 amino acids long (A bacterial global regulator forms a prion).

So that also is an example of a prion that comes from an unrelated bacteria c. botulinum infecting e. coli

Prions are often beneficial to bacteria - but what is benefiical to bacteria might not be so beneficial to their hosts - so are they a concern or not?

The roles of prions are still being unravelled. Prions seem to be rarely harmful in bacteria and frequently beneficial and may help bacteria to cope with stress (Protein aggregation in bacteria : conclusion). However making the bacteria better able to cope with stress could make them more infectious in hosts.

Prions were also found in Archaea in 2021, which means they are now found in all three of the domains of life, Eukarya, Bacteria and Archaea and were likely present in the Last Universal Common Ancestor of all terrestrial life. (The hunt for ancient prions: archaeal prion-like domains form amyloid-based epigenetic elements) which would seem to suggest a high chance of prions on Mars.

From these results, prions from an unrelated bacteria from Mars could in principle make a terrestrial microbe fitter - would that make it more harmful? The prions might be small, with an example of 68 amino acids. It might be necessary to look closer at this, to look at whether prions from Mars could

So it seems the Biological Safety Report was right to raise the issue of prions again, for the first time since 1997 and to recommend sterilization levels that would destroy them, at least until we know more. A review would need to look at what effects this could have on other organisms and the biosphere, if any.

This may very well conclude that there are no issues. However, given how very small prions are and hard to sterilize, it does seem to be an issue to look at, in a thorough study of the minimum size requirements.

Before we return unsterilized samples we need a size limit review - but before that we need an updated sample return review or both together

If we are going to return unsterilized samples to Earth, we need to do the size limit review first

We can’t develop a filter and / or air incinerator technology and relevant testing requirements, as requirements could change as a result.

But before we can do a size limit review we need to do an updated Mars sample return review (or do both together) so we know what to contain

Science has moved on hugely in the last 14 years since 2009 - many new discoveries e.g. very recent discovery through gene sequencing of "dark matter fungi" - fungi that infect microbes including fresh water algae - and marine algae - a "mystery yet to unravel"

Science has moved on so much in the last 14 years NASA surely needs a new Mars sample return review in 2023 similar to the ones from 2009 (Assessment of planetary protection requirements for Mars sample return missions) and 1997 (Mars Sample Return: Issues and Recommendations) 12 years before the 2009 study..

In my literature survey, I found there have been many advances in science relevant to a Mars sample return since 2009. That includes new discoveries of extremophiles including ones that also do well in normal conditions, capabilities of terrestrial organisms in Mars simulation chambers, new discoveries about terrestrial pathogens such as the very recent discovery of fungal parasites of blue-green algae (Discovery of dark matter fungi) (Basal parasitic fungi in marine food webs—a mystery yet to unravel), new potential habitats on Mars, new discoveries about the potential for life to be transferred in the Martian dust storms, advances in synthetic biology, new ideas about the potential for independently evolved life, and many other topics.

We surely need a new Mars sample return review before we can consider returning unsterilized samples to a receiving lab on Earth - like the study 14 years ago in 2009 and the earlier one 12 years previously in 1997 - each time we find more things that need to be considered

A new review is surely needed before NASA can be ready to do a new EIS, if the mission is going to return unsterilized samples to Earth. The 2012 ESF study focuses mainly on limits of size and filter requirements, and levels of assurance and is itself 10 years out of date now.

Planetary protection officer John Rummel's image of a train wreck for the permitted levels of terrestrial contamination of the samples- one of the last things your planetary protection experts warned you about before you closed down the planetary protection subcommittee

In 2017, your first planetary protection officer John Rummel referred to issues with your permitted levels of terrestrial contamination of the samples as a potential bureaucratic “train wreck” (With planetary protection office up for grabs, scientists rail against limits to Mars exploration).

This was one of the last things the Planetary Protection Subcommittee mentions just before they were disbanded: issues with terrestrial contamination of the Mars rover sample tubes. This is in the Planetary Protection Subcommittee report to the NASA Advisory Council, see: (NAC Science Committee, July 25-27, 2016: 9). For brief description of the context see (Review and Assessment of Planetary Protection … : 26–7)

Engineers worried that a sterile sample collection system would have to be transported to Mars in a separate bag - which might not open - a potential mission critical vulnerability

We do have the technology to make 100% sterile sample tubes free of any organics and to do the same for the sample collection tools. There are various ways to do this including baking the tubes and tools in an oven. However, engineers need a way to protect the tubes and tools from recontamination until after launch. The easiest way to do that is to put them in a bag to keep them sterile, but engineers worried this risks jeopardizing the mission, if Perseverance got to Mars and then they found that the bag couldn’t be opened

On the surface, the answer appears simple—put the sample collection tools inside an air-tight bag and transport it to Mars, keeping the material from ever coming in contact with Earth's atmosphere. But such a solution comes with its own problems.

"The engineers were very worried about this," Sessions said. "Imagine getting to Mars, and you can't get the bags open."

(How Much Contamination is Okay on Mars 2020 Rover?).

NASA went with the engineers here rather than the planetary protection advisors - in the process they achieved a mission with one less critical failure point - but sadly - one likely of virtually no interest for astrobiology

What we need to prevent in 2033: NASA like the Titanic headed for an iceberg - when scientists and the public realize NASA has no scientifically credible plans to protect Earth - and has permitted levels of terrestrial contamination that likely make its samples of virtually no interest for astrobiology past or present

John Rummel’s image) brought to mind the iceberg that sunk the Titanic. Here the iceberg represents public and scientific opinion in 2033 when they find out that

Text on graphic: What we need to prevent in 2033 - NASA’s mission plans - NASA’s future science credibility - Public and scientific opinion

(Stöwer Titanic)

(NASA logo )

Video: Open letter to NASA: Awkward questions, bonus samples and vivid scenarios to motivate space agencies to take planetary protection responsibilities seriously

No way to reliably distinguish terrestrial and martian biosignatures - the attempt at a genetic inventory turned up over 1000 distinct genera but with too few reads to identify them - and amongst the 54 genera that could be identified, found four species with less than 98.7% resemblance to the closest known species

We currently have no way to reliably distinguish terrestrial from potential martian biosignatures. We could recognize familiar life like chroococcidiopsis which we already cultivate and have already sequenced. However, the vast majority of microbial species haven’t been characterized or sequenced or cultivated in the laboratory; the problem of “microbial dark matter” (The search for microbial dark matter).

The iMost team suggested a genetic inventory:

To appropriately interpret evidence for Mars life in returned samples, we must be able to distinguish between terrestrial contaminates and indigenous martian life. For this reason, a genetic inventory of both the spacecraft and sample processing/analysis facilities is critical … A genetic inventory represents an important part of the background information related to detection of genetic material in Mars spacecraft and returned samples.

(iMOST : 94)

However the issue of microbial dark matter makes it impossible to achieve this goal. Hendrickson did an attempt at a genetic catalogue using 98 swabs from the floors of the clean room that would be used to assemble the Perseverance rover before assembly started. However,

So, over 1000 genera were known to be present but couldn’t even be identified. This is not unusual, indeed this is expected and normal.

They used the 16S RNA ribosome subunit for identifying microbial dark matter as it is very stable, and is the basis for the modern classification method for microbes and other organisms due to Carl Woese (The singular quest for a universal tree of life). It is a short section of RNA which gets mixed with proteins to make up the structure of the ribosome used to translate RNA into proteins.

We are certain to detect many novel sequences like this after taking them to Mars and back. So we will get many genetic sequence false positives, and it will be impossible to prove they aren’t martian.

But we can rescue this - with bonus samples in CLEAN containers sent on the EIS for astrobiology - a thimbleful of dirt, a few grams of dust, clean atmospheric samples, and a representative pebble from a recently excavated crater

The priorities of astrobiologists are different from geologists.

Present day life: with no in situ life detection, we'd likely need to drill into lots of boulders before we find patches of present day life if any.

For past life then we need to find rocks with a young exposure age..

This is why I suggested NASA and ESA collect bonus samples in STERILE containers sent on the ESA fetch rover (Comment posted December 20th). The aim is to return

For that last comment I have a rough calculation in the preprint:

Details in my preprint: (NASA must protect Earth's biosphere even if Mars samples hold mirror life...)

This shows how the atmospheric compressor works. It’s using a proposal submitted to the decadal survey in 2020 by Jakosky et al.

First it uses the getter to remove evolved gases from the container wall. Then it closes one microvalve and opens another to get an atmospheric sample. Finally it closes both microvalves to the gas container and opens the vent to run more atmosphere through the compressor to collect dust in the filter

(Scientific value of returning an atmospheric sample from Mars)

We can detect life from the Gobi and Taklimakan Deserts in dust in Japan (Aeolian dispersal of bacteria associated with desert dust and anthropogenic particles over continental and oceanic surfaces).

Text on graphic: Microbes in dust from the Gobi desert detected in Japan (Yonago).

Martian dust storms might transport dead or alive microbes great distances.

Graphic: distance gobi desert to Yonago

So we may have a chance of detecting viable or recently dead life from far away on Mars brought to Jezero crater in the dust storms.

For this we need:

The pebble would ideally be from a rock that has organics in it, perhaps Perseverance could analyse the same stratum - but far from the pebble so as not to contaminate it.

However we need to take great care with bonus samples too - Mars could have astrobiological surprises as astonishing as the carbon dioxide geysers were for geology - like mirror life

However we have to take great care with these bonus samples too.

NASA has made many extraordinary geological discoveries on Mars, such as the CO2 geysers.

Text on graphic: Artist’s impression of CO2 geysers on Mars, one of many geological surprises.

Mars could have astrobiological surprises too.

What if Mars has independently evolved mirror life?

Artist’s impression by Ron Miller of the martial CO₂ geysers that form in spring in the polar regions (PIA08660: Sand-Laden Jets (Artist's Concept), JPL).

When a molecule can occur in two mirror forms, like your hands, it’s called chiral - the word chiral is derived from the Greek word χειρ (kheir) for hand. Terrestrial life is homochiral, which means that nearly all of its asymmetrical (chiral) molecules occur in only one of its two mirror forms. Also terrestrial life for the most part can’t use any mirror organics it finds and just ignores them.

According to one theory - punctuated chirality - 50 - 50 chance that independently evolved life on Mars arose from a network of mirror organics interacting with each other - and still uses mirror organics

According to one modern theory - punctuated chirality - there’s a 50 - 50 chance that independently evolved life on Mars uses mirror organics.

According to this theory, early on as life was just starting to evolve, there were patches of chemicals that worked together with each other in chiral networks which expand converting a non chiral substrate into chiral organics and where two chiral networks of opposite chirality meet there are ways for them to slowly convert each other to the opposite chirality.

There would be many such patches, some with the same chirality as terrestrial life and some with mirror organics. According to this theory, these patches would expand and flip each other back and forth in chirality on an environmental scale, with the chirality reset multiple times in Early Earth even if it didn’t go extinct (Punctuated chirality : 6) until one of them got established as the basis for the evolution of life.

If so, depending on how the flips went on Mars, life could easily have evolved from the mirror chemicals of the ones Earth life evolved from.

“Our analysis predicts that other planetary platforms in this solar system and elsewhere could have developed an opposite chiral bias.”

(Punctuated chirality : 7)

Text on graphic: By the theory of punctuated chirality, in a large sample of glucose from many planets containing life or prebiotic chemistry, roughly half would be D-glucose and half L-glucose

D-Glucose which terrestrial life can use

L-Glucose used as an artificial sweetener

Similarly for all organics that can occur in two mirror forms

Graphic for L-glucose and D-glucose by reflecting the graphic horizontally. Grey: Carbon, Red: oxygen, white: Hydrogen.

Illustrative worst case scenario for effects on Earth's biosphere: INDEPENDENTLY EVOLVED MIRROR LIFE - specifically an analogue of the blue-green algae chroococcidiopsis - can radiate to survive almost everywhere on Earth - already adapted to metabolize normal organics because of infall from space

So, what if what we find on Mars is mirror life, or something even more exotic we haven’t considered before? It might be as remarkable as the CO2 geysers, but not safe to mix with our biosphere.

So that leads to this new scenario:

Text on graphic: Normal life, Mirror life, DNA, amino acids, sugars, fats, everything flipped. Most normal life can’t eat mirror organics. Martian mirror life might be able to eat normal organics.

To be more specific, in this scenario we might have a mirror life analogue of chroococcidiopsis on Mars.

Not Chroococcidiopsis flipped in a mirror, that would be absurd. But an independently evolved mirror life analogue of our blue-green algae on Mars with similar nutritional requirements and environmental preferences, but made up of mirror organics.

Illustrative worst case scenario for human health and wildlife (especially birds): NOVEL GENUS OF FUNGI from Mars able to infect us similarly to Aspergillus fumigatus - harms 200,000 a year, with high fatality rate and not adapted to an infectious lifestyle in any organism

I also developed a plausible scenario for a serious human pathogen to motivate taking great care to protect human health from large-scale impacts. It is also a good example to motivate taking great care with the Mars samples to protect birds (wild or domestic).

Paulussen et al put it like this:

Collectively, the aspergilli are remarkable fungi. … there are numerous aspects of Aspergillus cell biology and ecology (including their metabolic dexterity when adapting to nutritional and biophysical challenges) which contribute to their status as, arguably, the most potent opportunistic fungal pathogens of mammalian hosts.

Aspergillus species are able to utilize a wide range of substrates, highly efficient at acquiring such resources, and can store considerable quantities of nutrients within the cell; all traits which contribute to their energy‐generating capacity and competitive ability

…

Species of Aspergillus are also among the most stress‐tolerant microbes thus far characterized in relation to, for example, low water activity, osmotic stress, resistance to extreme temperatures, longevity, chaotropicity, hydrophobicity and oxidative stress

(Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species : section: Biophysical capabilities and ecophysiology of pathogenic Aspergillus species).

Those are all capabilities that would be very useful on Mars in the high stress, highly oxidising, low nutrient conditions there, as well as other adaptations of Aspergillus mentioned in that paper such as ability to respond to rapid hydration and ability to cope with low oxygen conditions in the lungs.

This shows how aspergillus fumigatus infects the lungs. First the wild fungus produces spores. The spores settle in the lungs. They then penetrate the lungs with hyphae (tendrils) which extract organics. It protects itself with chemical barriers and produces branching networks of these tendrils which then break up and spread through the body.

Text on graphic. The way a fungus infects us is very straightforward - insert tendrils (hyphae) to extract organics. Even an alien fungus with no adaptations to terrestrial life could do this. Uses chemicals to attack tissues. Also protects itself with chemical barriers.

Graphic from: (Aspergillosis - Creative Biolabs)

This is a close up of the details of how a spore (conida) lands on a surface and starts to grow into it.

Though the details are complex the basic way a fungus like aspergillus infect us is rather straightforward - it uses tendrils to extract organics and it protects itself with chemical barriers. It also uses chemicals such as acids or alkalis to damage the host tisue to help with breaking up the organics and to protect itself. These are things that even a fungus analogue from an alien unrelated biology might do.

Graphics from (Aspergillosis - Creative Biolabs).

Our body protects itself by using patterns that let it recognize the fungus. In a healthy immunocompetent person this is what happens in the lungs:

Text on graphic: How our body removes Aspergillus - this depends on recognizing it. This is the normal response - in some people our immune system over-reacts with an allergic response.

Graphic from: (Recent Advances in Fungal Infections: From Lung Ecology to Therapeutic Strategies With a Focus on Aspergillus spp. : figure 1)

A novel fungus like Aspergillus doubles as an illustrative worst case scenario for wild birds - birds are especially severely affected because they don't have an epiglottis, can't cough and have fewer cillia to remove spores from their lungs

This also doubles as a worst case for wildlife as Aspergillus is a serious pathogen of some wild birds (Aspergillosis in mammals and birds: impact on veterinary medicine) especially wildfowl, raptors and gulls (Cornell Wildlife Health Lab).

It also doubles as a worst case scenario for domesticated birds because Aspergillus often causes serious problems with turkeys and other poultry in farms. There is no treatment available for commercial flocks though pet birds can be treated (Aspergillosis in Poultry)

These are illustrative worst cases - there are many ways samples can be harmless - no life, not able to spread, can be contained in a BSL-4 or first microbes from Mars are harmless

These are worst cases.

In all the sample return reports to date, the experts have been of the view that the chance of returning a microbe capable of large-scale harm to human health or the environment like these examples appears to be low.

We may need vivid and clear illustrations like this to motivate space agencies like NASA to pay closer attention to how they develop their environmental impact statements

We need to prepare for worst case scenarios, and not just best case scenarios. We also need to set a good precedent for future samples returned from Mars.

In my literature survey, I found the existing planetary protection literature doesn’t have many actual concrete examples. However we may need vivid illustrations now, to help motivate space agencies to take more care. I have many more scenarios in the preprint. Some are of especial interest for alien life such as alien fungi, or alien life that doesn't respond to terrestrial life like microplastics or nanoplastics but could still harm us. See Main points in the open letter in more depth - selected highlights

NASA may be able to contain ultramicrobacteria and gene transfer agents with new technology - but it doesn't yet exist and needs to be developed first

You might be able to fulfill the ESF requirements with new technology. This technology would need to be developed, methods of testing it, repairing it, etc devised - which could take some years. The technology doesn’t exist yet as none of our biosafety laboratories need to contain ultramicrobacteria.

Even the most well prepared biosafety laboratory has to have emergency procedures for lab leaks

However, any biosafety laboratory with human technicians has to have emergency procedures in place for lab leaks.

Even the most well prepared laboratory may experience unintentional or intentional incidents or emergencies despite existing prevention or risk control measures.

(World Health Organization Laboratory biosafety manual, 4th edition : 87)

Video: Open letter to NASA: Need for a telerobotic facility because quarantine can't keep out mirror life or fungi, and how 100% protection in the forward direction can lead to an inspiring future for space settlement and colonization and a Mars with mirror life would stimulate space exploration

The Apollo missions used quarantine for technicians - but this was before NEPA and had no peer review - quarantine would not work to keep out mirror life or fungal diseases of crops - or diseases with life long symptomless human spreaders (similarly to typhoid Mary)

The Apollo missions used quarantine for technicians - Technicians for the lunar receiving laboratory had to go into quarantine at least twice after a breach of sample containment during sample handling, 11 technicians in an incident for Apollo 12 and 2 for Apollo 11 (When Biospheres Collide : 241. 485).

However this was before NEPA. The Apollo procedures were decided internally and only released on the day of launch. They were never subject to legal review or public scrutiny (When Biospheres Collide : 452).

Quarantine of technicians won’t work for mirror life, or fungal diseases of crops, or diseases with lifelong symptomless human spreaders. which could set up home harmlessly in the human microbiome.

The Apollo procedures wouldn’t keep out a life-long symptomless spreader of a pathogen similar to Mary Mallon for typhoid (Mary Mallon: First Asymptomatic Carrier of Typhoid Fever).

We’ll also see quarantine can’t work for fungal diseases of crops, and there are many other examples where quarantine of technicians can’t protect Earth.

For a vivid illustration, the ISS has a preflight “Health stabilization program” which uses vaccination and a 14 day quarantine to help prevent upper respiratory infection and gastroenteritis (Health Stabilization Program V1 4.4.2.4) but of course this can’t keep out fungi that are harmless to young healthy astronauts. Two of the Zinnia plants died from a fungal pathogen probably brought there by one of the astronauts.

Text on graphic: Mold growing on a Zinnia plant in the ISS. The mold fusarium oxysporum likely got to the ISS in the microbiome of an astronaut (Draft genome sequences of two Fusarium oxysporum isolates cultured from infected Zinnia hybrida plants grown on the international space station). (How Mold on Space Station Flowers is Helping Get Us to Mars)

This fungal disease disease fusarium oxysporum is also an occasional opportunistic pathogen of humans (Genomic Characterization and Virulence Potential of Two Fusarium oxysporum Isolates Cultured from the International Space Station)

This is just intended as an illustration to show that it's impossible to use quarantine to keep out a fungal disease. In this case, the fungus didn't kill the plants by itself. First, the plants got too much water, then four got mold. After a change to a higher fan speed two of the four infected plants recovered but two of them died (How Mold on Space Station Flowers is Helping Get Us to Mars) The strains isolated from the ISS weren’t able to infect healthy Zinnia plants (Genomic Characterization and Virulence Potential of Two Fusarium oxysporum Isolates Cultured from the International Space Station : 13). Other strains of fusarium oxysporum were found in isolates from the dining table in the ISS. (Genomic Characterization and Virulence Potential of Two Fusarium oxysporum Isolates Cultured from the International Space Station). Also we can’t know how this fungus got to the ISS, but it could be brought there on an astronaut’s microbiome.

However it's a vivid example to show how we can't keep fungi out of the ISS and it would be the same for any Martian fungi that can live in or on humans, most likely we wouldn't be able to keep them inside a quarantine facility. There are many other fungi on the ISS including Aspergillus fumigatus (Characterization of Aspergillus fumigatus Isolates from Air and Surfaces of the International Space Station) which is not likely to cause problems for healthy young astronauts and is commonly found in buildings.

Apollo quarantine was only designed to protect Earth from diseases with an incubation period less than 3 weeks - and even for those, NASA's plan was to rush any technician or astronaut who got seriously ill to hospital as an authorized breach of quarantine

You might wonder - what about the Apollo era quarantine of astronauts and technicians? The Apollo quarantine wasn’t designed by NASA to keep out all infectious diseases of humans. Their aim was to try to ensure any infectious disease brought back from the Moon had a long enough quarantine period so that we would have time to put measures in place to slow down spread of the illness. Richard Bryan Erb was the manager of the Lunar Receiving laboratory from 1969 to 1970 (The Early History of Canadian Planetary Exploration). He explained that the Apollo quarantine procedures were just intended to try to stop a pathogen with a short incubation period of less than 3 weeks (Edited Oral History Transcript).

You never know whether something might show up in thirty years. There are viruses and things that will show up long after the fact, but the theory was that if you can go through a quarantine for three weeks, which was the time set, without adverse effect, then you're obviously not dealing with something that is rapidly reacting and dangerous, so you would have time to prepare a remedial action. It was a good trade, I think, between a hazard, which was not very likely, but a risk of perhaps life on Earth, which was immense.

However, if a technician or astronaut became seriously ill and needed urgent treatment that wasn’t available within the quarantine facility, NASA’s stated plan was to immediately take them out of quarantine and to a hospital:

If a serious medical emergency had occurred that was beyond the capabilities of CRA (Crew Reception Area) equipment, NASA would have rushed the afflicted person from LRL [Lunar Receiving Laboratory] to a hospital, regardless of quarantine requirements

(When Biospheres Collide : 229).

So even if there was a rapidly acting pathogen and all the technicians got seriously ill quickly, they’d have been rushed to hospital, in an authorized breach of quarantine, so it wouldn’t have worked that well as a way to protect human health.

In the Apollo era NASA had an interagency panel - but all discussions were private and it was set up so no changes could be made to NASA's plans without NASA's own approval

NASA had an interagency panel for the Apollo quarantine discussions, but the discussions were private, and it was set up so all parties had to agree on any changes to NASA’s plans, including NASA itself.

… the regulatory agencies agreed “not to take any actions that might have an effect on the lunar program … without the ‘unanimous recommendation of the agencies represented on the [Interagency] Committee [on Back Contamination].”

… Since NASA was itself a member of ICBC, no actions could be taken without its approval.

(When Biospheres Collide : 193).

NASA used those powers to tell the astronauts to open the Apollo 11 door while still floating in the sea - against the objections of the National Academy of Sciences whose representative Vishniac said it would make the rest of the quarantine program pointless

NASA used those powers to block recommendations by other agencies, They often did object. For instance this was the view of Vishniac of the National Academy of Sciences on the plans to open the Apollo 11 capsule door and exit into a dinghy in the open sea:

Opening and venting the spacecraft to Earth’s atmosphere after splashdown would, in his view, make the rest of Apollo’s elaborate quarantine program pointless.

(When Biospheres Collide : 452).

But this was before NEPA. The Apollo procedures were decided internally and only released on the day of launch, and this was never subject to legal review or public scrutiny (When Biospheres Collide : 452).

So, the way NASA is behaving is very similar to the 1960s, NASA made decisions and other agencies had to follow their lead. This was easy back then, with almost no public awareness of the issues back then.

NASA is behaving in a similar way today - but the legal situation is now very different - as is public and general scientific opinion of the need to protect human health and the environment more rigorously

However, the legal situation is different now with NEPA. We also have far greater public interest and awareness in the potential for risks to Earth’s biosphere and human health. Though NASA could do this in the 1960s, they won’t be able to do it today, at least, not all the way through to 2033.

It was possible to design a mission even with 1960s technology to keep Earth 100% safe as with robotic technology and sterilized sample returns they could have quickly established that the Moon was sterile

It is impossible to know what scientists and the general public would have decided in the 1960s, if NEPA had predated Apollo 11. However there were ways that we could have made the Apollo missions completely safe, for instance using robotic sample returns similarly to the Soviet missions. It wouldn’t have impacted on the science return much to sterilize the first robotic samples. Then send humans once the Moon was confirmed to be sterile.

Reminder to NASA - you have a legal requirement under NEPA to consider substantive public comments such as the suggestion in my comments to use telerobotics to keep Earth 100% safe - which is also a way to chart a route for the Titanic to find its way back to clear waters

I'd like to remind NASA, of your:

In this open letter I suggest one possible direction to steer the NASA administration Titanic back into clear waters, avoiding the iceberg of public and scientific opinion in 2033, and maintaining your current world-leading role in planetary protection and Mars exploration science.

Because of quarantine issues - unsterilized samples have to be returned to a telerobotic facility until we know what's there - but many issues with a ground based facility - including end of life sterilization for mirror life -t nobody has done this before - and accidents and criminal damage (for high levels of assurance)

I concluded because of quarantine issues, unsterilized Mars samples have to be returned to a telerobotic facility, until we know what’s in them.

But there are many issues with a ground-based telerobotic facility too, such as

Also, it may be a requirement that the complete facility can be sterilized when it’s decommissioned, for instance if we find we have returned mirror life.

All Perseverance's samples would go to hold and critical review following the "safety testing" guidelines because of the terrestrial contamination at 8.1 ppb and because we don't have adequate contamination knowledge of what was sent to Mars

I found your “safety testing” wouldn’t work, either in orbit or on Earth. All unsterilized samples would go to “hold and critical review” for two reasons

In the COSPAR Sample Safety Assessment Framework, say that if life is detected it's not fasible to predict harmful or harmless consequences if life is detected: So safety testing consissts only of testing to see if there is any life there.

.Unfortunately, we have only a limited ability to predict the effects of terrestrial invasive species, emerging pathogens, and uncultivated microbes on Earths' ecosystems and environments. This is true even for cultured and fully genome-sequenced terrestrial organisms and more so for potential extraterrestrial life. Thus, conducting a comprehensive sample safety assessment with the required rigor to predict harmful or harmless consequences of potential martian life for Earth is currently not feasible.

 

.Conducting a comprehensive safety assessment with the required rigor to predict harmful or harmless consequences for Earth is not feasible. Therefore, the scope of the SSAF is limited to evaluating whether the presence of martian life can be excluded in the samples. Any possible hazard is only considered in the sense that if there is no martian life, there is no extraterrestrial biological hazard in the samples.

(COSPAR Sample Safety Assessment Framework (SSAF) | Astrobiology)

But the the high levels of contamination permitted by Perseverance would make that testing impossible.

One complication is that terrestrial biological contamination would impact the specificity of the test, that is, leading to a false positive.

...

(for step 7)

It is expected that this step could lead to a number of positive events that are likely associated with terrestrial contamination. However, until any evidence for life can be clearly associated with terrestrial contamination, the conservative assumption (positive hypothesis) is that it could be martian biology

(COSPAR Sample Safety Assessment Framework (SSAF))

To deal with that issue they refer to the need for contamination knowledge:

The contamination baseline for returned martian samples must be established from the CK [Contamination knowledge] obtained during the assembly of the various spacecraft that will fly as part of the MSR Campaign, along with blanks and witness samples returned with the martian samples

However as we saw above, we don't have that knowledge. Over 1000 genera were found that couldn't be read. Also the samples were very varied with for instance, 36 out of 49 spore forming species found in only one of the 98 swabs. See above:

The combination of the high level of contamination - and the varied composition of samples in the Perseverance rooms, would surely make it impossible to rule out terestrial contamination.

Even if we found a familiar genus such as chroococcidiopsis this doesn't show it is safe if we don't know it's from Earth - a novel Martian strain could have new capabilities evolved over billlions of years on Mars with new capabilities or novel toxins until we know more

Also - even if we found very familiar life, suich as another strain of chroococcidiopsis on Mars, it could have developed novel capabilities in the very different conditions on Mars. It could have added

Any of these could make it unsafe to return to Earth.It's especially likely that related strains on Mars could produce novel toxins. Microalgae produce many toxins. As an example, Chroococcidiopsis Indica produces BMAA, a neurotoxin which can cause Lou Gerig syndrome, the disease Steven Hawking had.(Diverse taxa of cyanobacteria produce β-N-methylamino-L-alanine, a neurotoxic amino acid) .( Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions).

There are numerous other toxins expressed by cyanobacteria and often they depend on a gene carried by a particular strain. According to some estimates, 25% to 75% of cyanobacteria blooms are toxic in one way or another (Toxins produced in cyanobacterial water blooms – toxicity and risks)

"Each toxin is produced by cyanobacteria only when the appropriate toxin gene is carried by a particular strain and if its expression is activated by environmental conditions

Cyanotoxins are usually classified in four classes according to their toxicological target:

  1. hepatotoxins that act on liver (Microcystins and Nodularin)
  2. cytotoxins that produce both hepatotoxic and neurotoxic effects (Cylindrospermopsin)
  3. neurotoxins that cause injury on the nervous system (Anatoxins, Saxitoxins and ß-Methylamino-L-Alanine –BMAA-) and
  4. dermatoxins that cause irritant responses on contact (Lypopolysaccharide, Lyngbyatoxins and Aplysiatoxin

(Cyanotoxins: methods and approaches for their analysis and detection)

These novel toxins could also be transferred to other microbes via gene transfer agents. More generally, we can’t know that unsterilized samples from Mars are safe for Earth until we have a much better understanding of Mars’s biosphere, if any, know what to look for, what its capabilities are and so on.

Safety testing can't be used at all if microbes occur in very low concentrations of only a few microbes per sample - even if, improbably, most of the sample was destructively tested for biosignatures, we couldn’t rule out a viable spore perhaps imbedded in a crack in a dust grain in the remaining fraction of the sample.

The COSPAR Sample Safety Assessment Framework (SSAF) refers to this problem that there is no guarantee that any Martian life has got into the subsamples examined.:

There is also another complication: even if there is life somewhere in the sample tube, there is no guarantee that there will be life in the subsamples that are examined.

(COSPAR Sample Safety Assessment Framework (SSAF))

This issue could be very acute in some scenarios

This was identified as a knowledge gap in the Space Studies Board review of SR-SAG2. The EIS uses SR-SAG2 but doesn't mention the Space Studies Board review of it, which was commissioned by NASA and ESA out of concerns that SR-SAG2

"The SR-SAG2 report does not adequately discuss the transport of material in the martian atmosphere. The issue is especially worthy of consideration because if survival is possible during atmospheric transport, the designation of Special Regions becomes more difficult, or even irrelevant."

Microbes could be transferred from distant parts of Mars and still be viable, for instance in fragments of biofilms (A desert cyanobacterium under simulated Mars-like conditions in low Earth orbit: implications for the habitability of Mars), They might also travel in bouncing sand grains ( Wind-driven saltation: an overlooked challenge for life on Mars).

Sagan suggested a viable microorganism could be imbedded in a dust grain and be protected from the UV by the iron oxides in the dust (Contamination of Mars. : 8)

Billi et al made a similar suggestion:

… Our findings support the hypothesis that opportunistic colonization of protected niches on Mars, such as in fissures, cracks, and microcaves in rocks or soil, could have enabled life to remain viable while being transported to a new habitat
( A desert cyanobacterium under simulated Mars-like conditions in low Earth orbit: implications for the habitability of Mars)

The largest dust grains detected by Curiosity reached above 6 microns in diameter for 3 days during the 2018 dust storm ( Large dust aerosol sizes seen during the 2018 Martian global dust event by the Curiosity rover : Figure 4 and discussion of it).

I can't find any experiments that test this hypothesis of microbial survival within dust grains with such large particles. If anyone reading this knows of such an experiment please let me know.

Perserverance has no in situ life detection capabilities and Martian life could be mixed with the dust, dark in colour, and not obvious to the rover. Perseverance could randomly sample the very edge of a colony or just outside it where a few stray microbes might still be found, at similar concentrations - of just a few cells per sample tube or even only one viable cell per gram or less.

So if we need a high level of assurance, we can't do safety testing even for bonus samples with no terrestrial contamination, because

We can’t know that unsterilized samples from Mars are safe for Earth until we have a much better understanding of Mars’s biosphere, if any, know what to look for, what its capabilities are and so on.

We can eliminate all these issues and make it a far simpler mission using a miniature telerobotic facility above GEO - for life detection and astrobiological research - NOT for safety testing - by 2033 we should be able to send all the instruments iMost recommended for present day life to orbit, in miniature

But we now have the capability to set up a miniature telerobotic facility just a few meters across above GEO due to the amazing shrinking in size of astrobiological life detection instruments designed for future in situ missions to Mars. Every decade the new instruments are even smaller.

Some are ready to fly today. Others are at an earlier stage of technological readiness but being actively developed, and may well be ready by the 2030s, and especially so if there is a strong incentive to complete them. Here are a couple of interesting examples:

I have a list of many more of these amazing shrinking instruments towards the end of this open letter. They would be able to make progress with all the measurements envisioned by the iMost team for present day life.

Text on graphic: Bonus samples in STERILE containers returned to satellite perhaps 50,000 or 100,000 km above GEO in what would be Earth’s ring plane if it had a ring system.

  • NOT for safety testing
  • Returned for astrobiological study – nexus of expanding off-planet astrobiology lab.
  • Minimal forward contamination.
  • Humans nowhere near this.
  • Centrifuge to replicate martian gravity.

Many instruments placed in centrifuge along with the dust and operated remotely from Earth.

  • Chiral labelled release.
  • SETG from sample acquisition through to DNA sequence all automated in 2 units, each can be held in palm of hand.
  • Astrobionibbler microfluidics can detect a single amino acid in a gram of sample

This would be minimal cost for NASA as the instruments would be funded by universities.

Graphic shows: (NOAA’s new GOES-17 weather satellite has degraded vision at night) just to have an image of a geostationary satellite, not that it would be a $2.5 billion dollar satellite. SETG from (SETG: nucleic acid extraction and sequencing for in situ life detection on Mars). Astrobionibbler from (Path to Discovery) ISS centrifugal motor for plant experiments, dialable to any level from microgravity to 2g (Centrifuge Rotor [biology experiment on the ISS])

Visually identical rocks in the same strata are usually interchangeable for geology - this is far from the case for astrobiology - we may need to search many rocks that are geologically identical to find samples of direct interest for past life

It’s also important to realize the situation is very different for life and for geology. With many scenarios the chance of detecting past life in samples returned from Mars is very low until we are able to search for it first in situ on Mars (Seeking signs of life on Mars: In situ investigations as prerequisites to a sample return mission) (Mars Extant Life: What's Next? Conference Report. (html) : 802). The life needs to be

In one plausible scenario Mars hadn't yet achieved photosynthesis 3 billion years ago - and may not even have it yet today - if so past life will be far harder to find and present day life might be too

For instance in one plausible scenario early life on Mars hadn’t yet achieved photosynthesis, or it never progressed to photosynthesis even today. If that is the situation, it could take a lot of searching to find past life.

Ancient martian environments may not have remained habitable long enough for photosynthesis to evolve, and a worthy avenue of research would explore how biosignature signals would be expressed and preserved in this different energy regime.

(Biosignature preservation and detection in Mars analog environments : Section 5. Urgent Needs and Future Research)

Our first samples from Mars returned without any in situ life detection may well be as ambiguous for astrobiology and lead to as much controversy as the structures in Martian meteorite ALH84001

Also if we do detect features that look like past life, what we return is most likely to remain ambiguous at this stage as for the Martian meteorite ALH 84001

A more likely scenario is that potential signatures of life might be equivocal, ambiguous or close to detection limits. Such samples might be considered lifeless by some workers and not by others.

…

Although Mars sample return and rover missions are strongly focused on finding evidence for life, lifeless samples returned from Mars will yield important constraints on the extent of habitable conditions and whether those environments were inhabited.

The scenarios discussed here show that it is critical to acquire many samples. Multiple samples must be obtained from each locality, from similar (paleo)environments elsewhere across Mars, and from different potentially habitable environments in multiple locations across Mars for the scenarios presented here to be disentangled and the reasons for lifeless samples ascertained.

(Lifeless Martian samples and their significance).

Even with bonus samples, it is important to present this to the public as just the second step in Carl Sagan's "Vigorous program of unmanned exobiology" after Viking as the first step - it would take a significant element of luck to find either past or present day life with the bonus samples - but we are guaranteed to find out much more about surface chemistry

Even with the bonus samples we should present this as just the second step in Carl Sagan’s “vigorous program of unmanned exobiology:

Carl Sagan: Because of the danger of back-contamination of Earth, I firmly believe that manned landings on Mars should be postponed until the beginning of the next century, after a vigorous program of unmanned Martian exobiology and terrestrial epidemiology.

( The Cosmic Connection – an Extraterrestrial Perspective)

The two Viking landers were the first step. We have sent no life detection missions to Mars since then. Also Mars is far more complex now than we thought when he wrote that. So we are likely to need many missions for a reasonably thorough exploration of Mars. We are at great risk of forward contamination if we send many robotic explorers to sensitive areas of Mars using the Perseverance level of cleanliness or even the far more rigorous Viking mission level of cleanliness.

It’s important not to present this to the public as the mission that will settle central questions of astrobiology. With better samples in clean containers, it may detect past or present day life, but it would take a significant element of luck to be so successful with a first mission.

Rather, this is the second step in our exploration of Mars to search for life (the Viking missions would be the first step as no mission since then has tried to find life).

One issue is to resolve the puzzling Viking labelled release measurements which suggests life or very complex chemistry - prebiotic or abiotic chemistry is important and will tell us a lot about what we have on Mars even if we don't find life yet

[Add section about the Viking experiments]

This suggestion of a miniature telerobotic laboratory would help NASA retaine your world-leading roll in planetary protection - and if we find life on Mars that can never be returned to Earth like mirror life it would be the core of a collaboration similarly to the ISS in miniature and at much lower cost for participating nations

My suggestion is just one solution, which I also mentioned in the final comment on your EIS (Comment posted December 20th). In this way you can move forward from this EIS with a new approach that would

What other suggestions might you get if you open up communications to other scientists and the general public in an open ended way? There may be many solutions just as there were many ways the Titanic could have avoided the iceberg - this suggestion just shows there is at least one way to do it

What other suggestions might you get if you open up dialog with the wider community of other agencies, international organizations and scientists in other countries, and the general public?

There may be many ways to do this, just as there were many ways the Titanic could have steered to avoid the iceberg - but the sooner this happens, the better, for NASA, for planetary exploration science, for astrobiology and for the public.

With Perseverance's samples and the bonus samples as just the second step in unmanned astrobiology on Mars - we need to prepare for many more missions to unravel the mysteries of the Martian biosphere if any - or prebiotic or abiotic chemistry there - the fastest way to do this is with sterile landers and rovers and we can do this now with HOTTech

I also recommend work on adapting the remarkable Venus HOTTECH technology (HOTTech) to achieve 100% protection of Mars and other destinations in our solar system from terrestrial life.

However, with (HOTTech), we can now build a probe which can be heated to 500°C without damage for months on end. We just need to be able to heat it to 300°C for a few minutes on the journey out to Mars to send 100% sterile rovers to Mars.

Pioneers - the 2018 largely mechanical automaton rover for Venus and Wilcox's 2017 design for a cryobot for Europa's ocean that can be heated to 500 C for sterilization

Video: NASA Engineers Design an Indestructible Venus Rover

The original idea was a wind powered almost fully mechanical rover on Mars.

The researchers proposed (in 2018) that the same approach could be useful for planetary protection because of their rover's resilience to heat sterilization, with an automaton rover explorer deployed from a more capable but less fully sterilized master rover to visit a nearby sensitive habitat (Automation Rover for Extreme Environments : Section 6.2).

In 2017, Wilcox designed a Europa probe that would be heated to 500°C on its journey out to Europa for complete sterilization (A deep subsurface ice probe for Europa)

These pioneering ideas have become much easier as a result of advances in technology for HOTTech in just the last 5 years. We now have the capability to build a fully functioning probe that can survive for months on the Venus surface at 500°C with the components needed for a science mission (Long-lived in-Situ solar system explorer (LLISSE) Potential Contributions to solar system Exploration).

The specification for a Marscopter that can be heat sterilized before it lands on Mars is far simpler than for a Venus probe - components need to function at normal temperatures after brief heating for a few minutes at 300°C and don't even need to function at 300°C never mind 500°C

I suggest we start with sterile Marscopters which would let our rovers send the marscopters to nearby features that they are not sufficiently sterilized to explore themselves and work up to a future where all missions to Mars are 100% sterile. This builds on a suggestion from the Venus lander team from 2018 which originally was almost fully mechanical.

We also have an electric motor and position sensor in development to operate at 500°C (HOTTech - position sensor). With

- it becomes far easier already to have 100% sterile probes for Mars based on (LLISSE). Eventually 100% sterile complete rovers.

Perhaps we could already build a Marscopter that could be sterilized to 300°C as it has relatively few components compared to Perseverance. Most of them seem to exist already in the (HOTTech) program and many others such as video cameras already exist in commercial use, for instance to look inside ovens, and could resist a few minutes at 300 C easily.

In summary, we are now able to protect Earth 100% in the backwards direction with almost all instruments needed for the iMost experients - with gene sequencers to complete the picture by 2033 and have a realistic possibility of 100% sterile rovers on Mars by the 2030s

Text on graphic: 100% planetary protection both ways, even if Mars has vulnerable early life, prebiotic chemistry, or mirror life.

Using NASA’s remarkable Venus HOTTECH technology, all these surface assets can be built to withstand months at 500°C, and so are easily sterilized with a few minutes of heating on the journey out.

Main image: “Safely tucked inside orbiting habitat, space explorers use telepresence to operate machinery on Mars, even lobbing a sample of the Red Planet to the outpost for detailed study." (Telerobotics Could Help Humanity Explore Space)

This is our choice as a civilization - I hope you agree that this is an interesting vision and one that is worth looking at carefully and proposing to the public as an alternative to dropping planetary protection

I conclude we have technology already to achieve 100% protection of Earth, and we have technology in development which could be accelerated to protect the rest of the solar system from terrestrial contamination, enabling 100% planetary protection in both directions, and we can do this with no loss of science return. Indeed by opening up the most sensitive areas of Mars, Europa’s ocean and so on to 100% sterile robotic explorers, this new technology has potential lead to a huge advances in science.

It is our choice as a civilization whether we do this.

Wie don't know which scenario we face - a Mars where humans can SAFELY explore the surface - or one where they can NEVER explore the surface safely or one where we need PRECAUTIONS such as quarantine to do it safely

I hope you agree with this, and we can work together to find a way forward to a stimulating future. We don’t know which of these scenarios we face:

That is why we need to do planetary protection. We need an open mind here, to look at this with clear eyes and develop a Mars exploration program that is inspiring and stimulating for both robotic and human missions no matter which scenario we face.

Mars is the only terrestrial analogue of Earth within light years - if it has interesting prebiotic or abiotic chemistry - such as flipping chiral networks - terrestrial contamination would make it impossible to study this in action - the order we introduce microbes might also matter for colonization

For there to be no issues to do with humans in the forward direction (as for the Moon) we need Mars to have:

We need a reality check on the timescale - it is easy to send dead humans to Mars but we don't yet have the technology for a self sutaining base on the Moon that can operate without resupply from Earth for severl years

We need to be realistic about the timescale for humans to Mars orbit - if we had that technology already we could set up a permanent base on the Moon with far less expense than for the ISS. NASA want to build a permanent base on the Moon. If we had the capability to send humans to Mars, we could send, say, a half dozen astronauts to the Moon with all the supplies they need for 3 years, and then leave them exploring and never need to send more supplies, replacement parts etc. This would make it very easy to establish a permanent base on the Moon. It would likely cost far less than the ISS. But we are nowhere near that level of technological readiness.

We couldn’t send an ISS clone to Mars, not safely. The ISS needs resupply every few months and they frequently need replacement parts from Earth when components fail.

The ISS crew also have lifeboat spacecraft attached to the station. Though it’s never been needed, they can get back to Earth in a few hours if they have a fire, chemical release, explosion, or a micrometeorite that damages the ISS to the extent they can’t repair it and need to evacuate right away. When we explore Mars it will be a two day medvac back to Earth. For missions to the Moon it’s nearly two years medvac if there is an accident just as the crew are leaving Earth on their way to Mars.

Chirs Hadfield - former commander of the ISS thinks ultimately we will be living on the Moon for a generation before we go to Mars - "It’s as if you and I were in Paris, paddling around in the Seine in little canoes saying, 'We’ve got boats, we’ve got paddles, let’s go to Australia!' Australia? We can barely cross the English Channel."

The retired Canadian astronaut Chris Hadfield, former commander of the ISS, interviewed by New Scientist, put it like this:

"I think ultimately we’ll be living on the moon for a generation before we get to Mars. If the world and the moon were threatened and the only way to preserve our species was to launch from Earth, we could go to Mars with yesterday’s technology, but we would probably kill just about everybody on the way."

(Chris Hadfield: We should live on the moon before a trip to Mars)

Frame from 28 seconds into this ESA video: Moon Village

If Space Colonization enthusiasts are right - they will have numerous assets on the surface by the time we are able to confirm their intuition that it is safe to colonize Mars - very important with an evacuation time of a minimum of six months

If space colonization enthusiasts are right that the two biospheres are compatible, by the time humans get to Mars they will have numerous assets on the surface of Mars already.

This compares evacuation times:

ISS emergency evacuation a few hours, resupply every few months < day to arrive

Moon emergency evacuation 2 days, resupply takes 2 days to reach the Moon

Mars emergency evacuation minimum 6 months, emergency resupply minimum 6 months to arrive

(added text to this infographic from the Canadian space agency: Distances between Earth and the International Space Station, the Moon and Mars - infographic)

Meanwhile using artificial real time from computer games and fast bandwidth communications from Mars we can explore Mars from our own homes on Earth as if we were there - even look at rocks with a hand lens based on a virtual 3D world built up from gigapixel streaming video from Mars

Meanwhile, we can speed the Mars exploration so much that using this idea of "artificial real time" from computer games, we can control our rovers almost as easily as a rover on the Moon (say), which NASA will be able to do once you have broadband optical laser communication with Mars later this decade.

It works by simulating the position of your rover as it will be when the commands get to Mars, so you can drive in a virtual landscape in real time with no latency, a technique used in online multiple player games. In this video he talks about using way points - so you tell the rover where you want it to go, and so long as the waypoints are ahead of where it has got to it doesn’t slow down.

Video: Telexploration: How video game technologies can take NASA to the next level

This was later developed into OnSight using Microsoft’s “hololens” software.

Video: Walking on Mars w/ HoloLens [OnSight]

For more about it: (Immersed on Mars — Dr. Jeff Norris)

It will help also to have more autonomous and more rugged rovers.

By the 2030s with fast bandwidth and once we have gigapixel video cameras on Mars we’ll have scenes like this, but far higher resolution than this, building up a 3D virtual world in microscopic detail as the rovers traverse Mars.

(First 4.5-billion-pixel of Mars by NASA's Perseverance Rover)

With gigapixel video cameras on the rovers, streaming back broadband to Earth, scientists and enthusiasts will be able to look at the landscape on Mars with a virtual hand lens, examining any rock the rovers ever passed by in microscopic detail. Their discoveries could then lead to the rover turning around and looking at the rock again - but as rovers get faster, able to move tens of kilometers a day as for the lunar rovers or even faster - and not limited like the lunar rovers were, to remain within walking distance of a base (The Apollo Lunar Roving Vehicle). We need far faster and more robust rovers for human exploration if we do get humans on the surface. We can send them there first, for robotic exploration.

For astronauts in orbit around Mars it would be not unlike playing a game of "civilization" with many semiautonomous rovers on the surface, driving by themselves with assistance from Earth already

In this way we would have many assets already in place when the astronauts get there, and data links working and tested, and capable teams on Earth to do most of the heavy work leaving it for the astronauts in orbit to be used to their maximum for the executive capabilities. For them it might be not unlike playing a game of “civilization” stepping in from time to time to help one of the robots that is stuck on some task or needs to be operated directly for some time sensitive experiment.

So we can do a huge amount of exploration on Mars from Earth in the very near future, and all this with those near future 100% sterile rovers that can explore anywhere with no planetary protection restrictions. All of this builds up assets on Mars and knowledge about Mars that will be very useful when humans get there, whether in orbit or on the surface.

If the colonization enthusiasts are right they get a "pass" and have much broader backing because the rest of our civilization knows they are right - hardly interrrupting their plans- and if they have to stay in orbit - they can use those asets to exploit Mars and even set up robotic farms on the surface which would work even on a mirror life planet because seeds can be sterilized unlike humans

The Mars colonization enthusiasts are so sure that the Martian biosphere will be safe for Earth. If they are right we will get a “pass” as a result of this exploration. It will hardly interrupt their plans at all if their confidence is well placed. Not only that they would get much broader backing because their confidence will be based on scientific knowledge about Mars rather than optimistic hunches and vivid metaphors.

While if they have to stay in orbit, and colonize the moons of Mars, they can use these assets to exploit Mars with robotic exports to their colony, even grow plants on the surface.

Though we can’t sterilize humans, we can sterilize seeds without any risk of contaminating Mars with Earth micro-organisms.

Text on graphics: We could grow plants on Mars even if it has mirror life that can never be brought back or Earth has microbes can never be sent to Mars.

Seeds can be sterilized and grown in sterile aquaponics

(The Real Martian Technologies: Our Little Green Friends)

In this way we could have greenhouses on the surface of Mars and these could grow food for the colonists in orbit. They may have plenty to eat in their habitats anyway by then, but they might grow maybe delicacies or things that grow particularly well on Mars or medicinal plants or whatever. Also they might grow large plants, and maybe trees (perhaps growing far larger in the Mars light gravity) or whatever else grows best on the surface of Mars, or for convenience to save space in orbiting habitats.

We can in principle grow many terrestrial crops on the surface of Mars with no risk of contamination in either direction, on most scenarios. We could export those crops to the orbiting colonies, for instance on Phobos. We can also do mining for minerals on Mars, and prospect for assets that may be worth selling to Earth and so on, do everything the colonization enthusiasts want to do except humans on the surface, much like the game of civilization with robotic avatars.

I believe the general public needs to be aware we have this choice as a civilization - and the decision needs to be made on a broader basis than internal technical discussiosn within NASA - to find a way forward that is better for NASA, for the general public, for planetary science, for your reputation - and good for space colonization enthusiasts too whatever their views on the need for planetary protection

I believe the general public needs to be aware 100% protection is available and is scientifically feasible in both directions. This decision needs to be made on a broader basis than internal technical discussions within NASA. So it’s important to open up discussion and engage more generally with other agencies, your former planetary protection officers, and the general public. More generally it seems clear you need to move in the direction of more not less communication with others as you work on the project.

By sending this open letter I hope to encourage you to participate in a wider discussion with experts of many disciplines and the general public in order to find a way forward that is good for NASA, for the general public, for planetary science, and for your reputation. Also to find a way forward that is good for the space colonization enthusiasts too whatever their views on the need to protect Earth's biosphere. I am presenting here some of the things you will need to listen to in the future. I hope this will lead you to a more open direction.

[I’ll archive this open letter with a doi in a preprint server for future reference before sending it as for my preprint - url to preprint here]

SHORT FORM OF INLINE CITATIONS FOR THIS OPEN LETTER

To simplify the citations I just give the title of the paper hyperlinked to the online text of it, in brackets. I add page numbers or section headers if needed.

Example: (A citizen’s guide to the NEPA: Having your voice heard : 28)

VIDEO PRESENTATION

[once ready]

SUMMARY OF THE MAIN POINTS

Let’s look at a summary of the main points. These were posted on the last day of public comments to your draft EIS.

Since then my preprint and literature survey added many more details but hasn't led to any changes in those main points.

I recommend this draft Environmental Impact Statement is stopped, and a new one prepared after doing the necessary size limits review, and fixing whatever led to its many errors.

1. The BSL-4 recommendation in this EIS is out of date, based on science of 1999.
2. This EIS does not mention the most recent Mars Sample Return study from 2012 by the European Space Foundation which reduced the 1999 size limit from 0.2 microns to 0.05 microns to contain ultramicrobacteria and required 100% containment at that size.
3. A BSL-4 is not designed to this standard. In recent reviews of filter technology, I find NO AIR FILTERS with that capability – and no evidence anybody is working on them. Air filters for larger particles remove some of these very small particles kicked out of the airstream by jostling of air molecules by Brownian motion but can't remove all. It is an unusual requirement.
4. NASA haven't responded to my comment in May which alerted them to this omission. They still don't cite the ESF study. Also, the ESF said their limit needs to be updated periodically. An update is certainly due a decade later.
5. The EIS has an overnarrow scope in the Purpose and Need section - it requires samples to be returned unsterilized to terrestrial labs for "safety testing". This won’t work. NASA believe they reduced the most abundant biosignatures to 0.7 nanograms per gram of returned rock sample – this guarantees a positive test. There will be no way to know if tubes contain safe terrestrial life or potentially unsafe martian life.
6. This narrow scope improperly excludes the reasonable alternative of presterilizing samples before they reach Earth's biosphere - which achieves virtually the same science return and keeps Earth 100% safe. By a 1997 case in the 7th circuit this alone probably invalidates the EIS.
7. The high levels of forward contamination make astrobiology almost impossible. I recommend bonus samples of dirt, dust and atmosphere collected in a STERILE container with no terrestrial organics, brought to Mars, especially on the ESA fetch rover.
8. I recommend returning these bonus astrobiology samples to a safe orbit above GEO where they can be tested for life
9. The EIS’s reasoning for no significant environmental effects contradicts the conclusion of the NRC study from 2009 which they do cite, which says the risk of even large-scale impacts on human health or environment is likely low but not demonstrably non zero. It also warns against the meteorite argument that they use. I found multiple errors in my analysis.
10. Returned life COULD be harmful. Example, fungi kill crops, other life and sometimes immunocompromised humans. Botulism, ergot disease, tetanus, all are the results of exotoxins not adapted to the lifeforms they kill, similarly some algal blooms kill dogs and cows that eat them. BMAA misincorporated for L-serine causes protein misfolding and is a neurotoxin implicated in some cases of the disease that affected Steven Hawking - an alternative biochemistry may have many different amino acids similar enough to terrestrial amino acids to be misincorporated. Or perhaps martian life evolved from scratch from mirror chemicals as mirror life - the effect on our biosphere can't be predicted. I give many such examples in my preprint. Or it could be harmless like microbes from a terrestrial desert, or indeed beneficial. But we DON'T KNOW. So we need to find out first.
11. What matters for invasive species are the ones that can’t ‘get here, like starlings that can't cross the Atlantic rather than barn swallows. The freshwater diatom Didymo is invasive in New Zealand and can't get from one freshwater lake to another without humans. A microbe adapted to briny seeps on Mars and to spreading in dust storms shielded frbiom UV, may well not get to Earth in a meteorite, while a sealed sample tube including Martian atmosphere, at Mars atmospheric pressure, is like a mini spaceship.
12. Quarantine of humans can’t keep out a fungal disease of crops, mirror life etc.
13. So any unsterilized samples will need to be studied remotely via telerobotics which also greatly reduces forwards contamination (issues with filtering ultramicrobacteria will go both ways).
14. Astrobiologists now have tiny instruments that can go from sample preparation to life detection, even to a gene sequence[r], operated remotely on Mars. They could send hundreds of these in each 7 ton payload of the Ariane 5 to above GEO.

Let's make this an even better mission and SAFE for Earth.
Thanks!

. Comment posted December 20th

SUPPORTING MATERIALS

This open letter is like an extended abstract. It touches on some of the main points of interest to NASA.

My survey is preliminary but one thing it shows so clearly is how multi-faceted planetary protection is. We need to involve scientists from a very wide range of disciplines and an interagency panel can help with that.

None of the previous sample return studies even back to Apollo mentioned Mary Malone or the topic of a lifelong symptomless spreader, which would be the first thing an epidemiologist would think of.

This is not surprising, and not a criticism of the excellent work done on planetary protection by NASA and others. It is just a symptom of the vastness of the topic of planetary protection and it also shows how this topic is under-resourced relative to its extraordinary complexity. The lack of a mechanism for inter-agency dialog on this matter doesn’t help.

We need to open this up for public participation, not just to keep the public informed and involved, but also because others with other backgrounds may spot issues or solutions that nobody else thought of before.

I keep finding new things. Even while writing this open letter over the last couple of weeks I’ve found more new things that need to be integrated back into the preprint. There is no way this is a complete literature survey. It just touches on some of the points a more comprehensive review would be likely to consider.

The advances in science has been so extraordinary in so many topics relevant to a Mars sample return in the last few years. This open letter and my preprint just touch on some of the more significant new developments since the last major Mars sample return review in 2009 (the 2012 ESF study focused mainly on limitations of size and the smallest organisms that can get through nanopores).

I have a longer version of this open letter which goes into more detail on many topics

Main points in the open letter in more depth - selected highlights

Joshua Lederberg, a key figure in early work on planetary protection (How the Cold War Created Astrobiology, Life, death, and Sputnik) put it like this

Text on graphic: Joshua Lederberg, winner of a Nobel prize in 1958 for his discovery of bacterial sex.

Whether a microorganism from Mars exists and could attack us is more conjectural. If so, it might be a zoonosis [infectious disease that jumps to humans] to beat all others.

Quote from: (Parasites face a perpetual dilemma)
Photograph from: (Joshua Lederberg)

I found a new approach that makes it possible to look at this issue even without any examples of an alien lifeform to test.

I look at recognition of “non self”. Our defences against harmful microbes have to distinguish between our cells and harmful cells. So I looked at how the natural antimicrobial peptides in our body’s first line of defences work. Some of them are broad spectrum and work against bacteria. These would work against alien life if it has cell walls coated in acid groupings like bacteria but not if they have neutral cell walls like fungi or other eukaryotes. There seems to be no particular reason why the cell walls of alien life would resemble bacteria more closely than fungi. Antifungals have to work in a narrower more specific fashion that is unlikely to work with an alien biology.

Text on graphic: Antimicrobial peptides (short protein chains). Our body’s first line of defence against microbes.

Recognizes “non self” as negatively charged cell walls (acids)

Very general but won’t work if alien life has neural cell walls

May work with some alien life.

Internal target structures.

Less likely to work with alien life.

(Antimicrobial Peptides in Human Sepsis : Figure 1)

I look at fungal infections, including fungal infections of microbes, that have a mechanism that could be used by an alien microbe, to insert tendrils into a host from outside to extract its organics. The discovery of fungal infections of bacteria and other microbes is very new. This discovery is too recent to be covered in the 2009 Mars back contamination study. It’s an example of what John Rummel said:

We keep finding Earth organisms doing new things that are quite interesting from the standpoint of potential life elsewhere.

(Controversy Grows Over whether Mars Samples Endanger Earth)

Researchers found these dark matter fungi as a result of advances in rapid gene sequencing. They called them “Dark Matter Fungi”, so called because they are not easy to study or cultivate (Discovery of dark matter fungi in aquatic ecosystems demands a reappraisal of the phylogeny and ecology of zoosporic fungi).

Text on graphic: How chytrid fungi attack diatoms. Alien organisms could do the same, insert filaments to extract organics.

Description: false-colour red shows chytrid-like [zoo-]sporangium structures.

(Chytrid fungi distribution and co-occurrence with diatoms correlate with sea ice melt in the Arctic Ocean - Communications Biology : Figure 7)

Early research focused on fungal diseases of fresh water microbes. However more recently, scientist discovered that there are many fungal diseases of marine microbes too. They just found the freshwater ones first. A review from 2022 describes them in the title of the paper as a “mystery yet to unravel” (Basal parasitic fungi in marine food webs—a mystery yet to unravel)

I look at nanoplastics and microplastics as an analogue of alien life that may not even notice terrestrial life. Though microplastics and nanoplastics don’t attack our bodies and can’t reproduce they can impact on our immune system in various ways, including coronas, the blood plasma sticks to nanoparticles of some types of plastic, in this case polystyrene

Text on graphic: Microplastic. Blood plasma sticks to the microplastic. Corona can pick up fragments of pathogens. This can trigger an inflammation response.

These can then coagulate to form blood clots:

Text on graphic: Plasma coronas can cause the microplastics to stick together and form blood clots

These figures are from: (Assessment on interactive prospectives of nanoplastics with plasma proteins and the toxicological impacts of virgin, coronated and environmentally released-nanoplastics)

I look at the possibility that an alien lifeform with novel amino acids might cause protein misfolding similarly to the misfolding that results from incorporating BMAA in place of serine.

Some of these novel amino acids might be like BMAA and bind to transfer RNA (Transfer RNA (tRNA) ) for a similar amino acid, through accidental similarities and so get misincorporated. Like this:

Video: From DNA to protein - 3D
Frame from here
How the transfer RNA molecules work is explained here in the video
For a video that shows more realistic shapes for the molecules see: From DNA to Protein

This may be a contributing cause to neurodegenerative diseases such as ALS which Steven Hawking suffered from, as it can bind to serine transfer RNA and so get misincorporated into proteins in place of serine (The emerging science of BMAA: do cyanobacteria contribute to neurodegenerative disease?).

I also look at

and many other topics. See:

Executive summary highlights

The executive summary for the preprint covers much of the same ground as the open letter. However it has some new material that may be of interest.

For instance it covers some recently postulated microhabitats on mars including cryoconite holes - which could be a fresh water habitat in polar regions on Mars

Two ice covered cryoconite holes on the left and sketch of how they work on the right (Measuring and modeling evolution of cryoconite holes in the McMurdo Dry Valleys, Antarctica)

These cryoconite holes have been proposed as a way that life could survive and propagate in the polar ice caps on Mars, as well as possibly comets and Europa (Microorganisms on comets, Europa, and the polar ice caps of Mars) (The search for a signature of life on Mars: a biogeomorphological approach : 14)

It discusses this remarkable photograph from NASA’s Mars reconnaissance orbiter of a crater that was detected by the small earthquake tremors it generated as it impacted on Mars by NASA’s Insight Lander.

(NASA’s InSight Lander Detects Stunning Meteoroid Impact on Mars)

This crater threw up boulders from the subsurface of the Amazonis Planitia region on the flanks of Olympus Mons, the largest known volcano in the solar system which has been geologically active recently and is clearly not yet dormant. This is especially interesting for recent or even maybe present day life because lava flowed there less than 24 million years ago. There’s discussion of whether those ice boulders, and perhaps cryoconite holes in them could host present day life, and of the importance of developing 100% sterile landers to study these and other interesting sites on Mars in situ, to look for life and return it if found.

It discusses the 2014 MEPAG report SR-SAG2 (A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) which is the source for this statement:.

Draft EIS: (paraphrase) If there is life on Mars it can’t get into Perseverance's samples in Jezero crater:

“Consensus opinion within the astrobiology scientific community supports a conclusion that the Martian surface is too inhospitable for life to survive there today, particularly at the location and shallow depth (6.4 centimeters [2.5 inches]) being sampled by the Perseverance rover in Jezero Crater, which was chosen as the sampling area because it could have had the right conditions to support life in the ancient past, billions of years ago. (Rummel et al. 2014, …)”

.. MSR DRAFT EIS 1–6

What they don’t mention there (may not know?) is that NASA and ESA took the very unusual step of commissioning an independent review that found many knowledge gaps not adequately covered in SR-SAG2 and especially on topics relevant to whether there could be life in Jezero crater.

There were two reasons why both agencies [NASA and ESA] took the seemingly unusual step of independently commissioning reviews of a review paper that was to be published in a peer-reviewed journal.

First, there is the perception in some circles that MEPAG is not independent and that its views are too closely aligned with NASA’s Mars Program Office.

(Review of the MEPAG report on Mars special regions: xi – xii).
[by the Space Studies Board, the European Space Sciences Committee and the National Academies of Sciences, Engineering, and Medicine]

It is a serious omission for the Environmental Impact Statement to use SR-SAG2 as a source and not cite this critical review of it..

I discuss this review and some of the knowledge gaps they identified. Particularly, this review found that SR-SAG2 doesn’t adequately discuss the transport of material in the Mars atmosphere [e.g. in dust storms] see page 12. Amongst several relevant discoveries, later research found small fragments of biofilm, thin layers of a microbial colony three hundredths of a millimeter thick, can travel 100 kilometers in daylight in the light Martian winds before it is sterilized (A desert cyanobacterium under simulated Mars-like conditions in low Earth orbit: implications for the habitability of Mars)

(An Overview of Biofilm Formation–Combating Strategies and Mechanisms of Action of Antibiofilm Agents : Figure 1)

Mosca et al. suggest that a biofilm could still propagate on Mars in this way as complete biofilm fragments, even if local conditions don’t permit it to establish a biofilm today by slowly growing from a few microbes. All that is needed is that at some time in the past biofilms were able to form, propagating ever since then using these broken off fragments 2019. (Over-expression of UV-damage DNA repair genes and ribonucleic acid persistence contribute to the resilience of dried biofilms of the desert cyanobacetrium Chroococcidiopsis exposed to Mars-like UV flux and long-term desiccation)

The newer research also turned up a new way that microbes could be transported on Mars, in bouncing sand grains.

Text on graphic: Bouncing dust grains or propagules would travel 250 to 850 kilometers per day in a dust storm (at typical saltation speed of 3 to 10 meters per sec).

Dust grains on Mars of 500 microns diameter can bounce up to several meters with each bounce with a height of tens of cms.

A biofilm propagule this size covered in iron oxide microparticles for protection from UV could contain over 24 million microbes at 1 micron diameter.

Artist’s impression of a typical bounce based on figure 2b from (Giant saltation on Mars) superimposed on photograph of the top of a large sand dune taken by Curiosity on December 23, 2015 (NASA Rover's Sand-Dune Studies Yield Surprise)

Other experiments show that though most microbes that get trapped in a dust grain are quickly destroyed by the shock of the impact bounces, a fraction of a percent remain viable after transport ifor the equivalent of hundreds of kilometers travel in bouncing sandgrains ( Wind-driven saltation: an overlooked challenge for life on Mars)

All this leads to an intriguing possibility. If microbial life can be transferred in dust storms - but perhaps rarely and only some species make it, perhaps every 100,000 to 500,000 years, then Mars could have islands of habitability for microbial life with some species common to all the regions but others diversify into niche species that can’t be transported far in the dust storms and that have evolved locally for millions of years or more.

(Extinction and Biogeography of Tropical Pacific Birds)

It's also got some suggestions abotu Nilton Rennó's suggestion that a biofilm could make the Curiosity brines habitable - combined with recent research that finds that terrestrial mosses may be good Mars analogue organisms - could Mars have moss like organisms that absorb water fast in the early morning when Curiosity found ultra cold salty water even on the surface at -73°C - and retain it even through to midday on the same day when temperatures reached over 15°C?

Curiosity found liquid water in the salts that take up water at night - on the surface through to 6 am on the same day that it measured surface brines for the last time in the year, it registered a midday temperature of 15 °C (Transient liquid water and water activity at Gale crater on Mars.figure 3a and 3 c) Those brines are habitable but too cold for terrestrial life at -73°C at 6 am on that day. But could life somehow retain that water through to warmer conditions?

These brines are an example of the SR-SAG2

“Brine-related Liquid water in deliquescing salts, in channels within ice, on the surface of ice, within salt crystals within halite or other types of ‘rock salt’”

(A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : 904)

Nilton Rennó, an expert on Mars surface conditions, who was part of the team that discovered the Phoenix lander drops, principle investigator for Phoenix and who also runs the REMS weather station on Mars for Curiosity, suggested in an interview that microbes might use biofilms to inhabit these brines

"Life as we know it needs liquid water to survive. While the new study interprets Curiosity's results to show that microorganisms from Earth would not be able to survive and replicate in the subsurface of Mars, Rennó sees the findings as inconclusive. He points to biofilms—colonies of tiny organisms that can make their own microenvironment.

(“Mars liquid water: Curiosity confirms favorable conditions”)

These would likely be a mix of many species working together for extra resilience like the grit crust in the Atacama desert (The grit crust: A poly-extremotolerant microbial community from the Atacama Desert as a model for astrobiology)

I have a section in my preprint speculating that these biofilms could also include mosses that might take up water when its very cold just passively - and then they might retain it through to daytime when temperatures go up to above 15 C in Jezero crater. Huwe et al. tested a moss Grimmia sessitana collected in the alps in a terrestrial Mars simulation chamber in 2019 (Mosses in low Earth orbit: implications for the limits of life and the habitability of Mars) and also tested in BIOMEX, the Mars simulation experiment that was attached to the outside of the ISS (Limits of life and the habitability of Mars: the ESA space experiment BIOMEX on the ISS) though I can't find the results of that experiment.

Huwe et al. tested rapid day night cycles from -25°C to 60°C which had no effect (Mosses in low Earth orbit: implications for the limits of life and the habitability of Mars) . They didn’t need to cycle it all the way down to below -70°C as it has already been shown to be able to survive immersion in liquid helium at only 0.65°C unharmed (Freeze avoidance: a dehydrating moss gathers no ice). They found that vacuum and the Mars like atmosphere had no effect on it. (Mosses in low Earth orbit: implications for the limits of life and the habitability of Mars)

In my preprint, based on these experiments, I speculate Mars could have microscopic moss like plants, which can absorb water rapidly, in seconds, and retain it for a long time The desert moss Syntrichia caninervis which is found in desert biocrusts throughout the world uses microgrooves rather than micropores, with an “upside-down” water collection system that collects water droplets which condense onto microgrooves within its leaf hair points and it rapidly funnels those down to the plant below (Effects of leaf hair points of a desert moss on water retention and dew formation: implications for desiccation tolerance).

Video: Demystifying desert moss hydration

The leaf hairs

This reduces evaporation from the hydrated moss for as long as it has high water content.

Those microgrooves are like a biological analogue of the Atacama salt and gypsum pillars micropores. So - might not Martian life have developed similar structures over billions of years of evolution on Mars? Microgrooves or micropores, or some other structures optimized to collect and retain water in cold conditions, passively, mechanically when it is too cold for metabolic processes.

More speculatively, some mosses can open and close pores (stomata) like plants ( . Regulatory mechanism controlling stomatal behavior conserved across 400 million years of land plant evolution. ). . I couldn’t find a paper about terrestrial biocrust doing this, but could a biofilm be covered by a martian organism that evolved pores that close in daylight like the stomata of cactuses to hold in the water?

Text on graphic: Guard cells (swollen) Stoma opening. Guard cells (shrunken) Stoma closing

Text on graphic: Guard cells (swollen) Stoma opening.
Giuard cells (shrunken) Stoma closing
(Opening and closing of stoma)

 

The executive summary also discusses the many international treaties and local laws that are relevant to a Mars sample return once it acknowledges a low likelihood of large scale harm to human health and to the terrestrial biosphere and other organisms in it.

It also discusses parallels with the Challenger O-ring disaster.

Video: Richard Feynman debunks NASA

The issue with the O-ring that Richard Feynman demonstrated in that simple experiment using iced water were already known before the accident. But the investigation after the accident found that the high administration in NASA in a top down approach were not alerted to issues raised by some of its technicians (Report to the President by the Presidential Commission on the Space Shuttle Challenger Accident : 85).

This is all discussed in the executive summary here:

Finding an inspiring future highlights

Earlier in this open letter I talked about how NASA needs to plan in a more flexible way where we have a future that is inspiring and encourages space exploration and settlement for ALL scenarios,

We can do this in a way that leads to broadband communications with Mars ready and tested and in constant use early on, which will be a major asset for robotic missions, and many assets on the surface, all ready for humans in orbit. This leads to exciting missions in orbit around Mars.

Then if the Mars colonization enthusiasts are correct in their assessment that Earth’s biosphere is safe for Mars and the Martian biosphere, if any, is safe for Earth, they can soon progress to the surface. If Mars has something that can never be returned like mirror life, we continue to explore from orbit. I talk about how stimulating a mirror life planet (or other exotic life) in our solar system can be for future space exploration and settlement throughout the solar system.

This is something I also explore in the preprint and here is an executive summary of those sections.

The retired Canadian astronaut Chris Hadfield, former commander of the ISS, interviewed by New Scientist, put it like this:

"I think ultimately we’ll be living on the moon for a generation before we get to Mars. If the world and the moon were threatened and the only way to preserve our species was to launch from Earth, we could go to Mars with yesterday’s technology, but we would probably kill just about everybody on the way."

"It’s as if you and I were in Paris, paddling around in the Seine in little canoes saying, 'We’ve got boats, we’ve got paddles, let’s go to Australia!' Australia? We can barely cross the English Channel. We’re sort of in that boat in space exploration right now. A journey to Mars is conceivable but it’s still a lot further away than most people think."

(Chris Hadfield: We should live on the moon before a trip to Mars)

Frame from 28 seconds into this ESA video: Moon Village

The lunar caves are truly vast far larger than lava tube caves on Earth. Some may be up to kilometers wide. Some of the lunar caves probably have an internal steady temperature of around -20 °C, potentially useful as a constant heat sink for a settlement (. Lunar and martian lava tube exploration as part of an overall scientific survey) The challenge of providing energy during the lunar night is a similar challenge to providing energy during Martian dust storms. Then there are the peaks of almost eternal light at the poles with solar power 24/7 nearly year round (Peaks of Eternal Light), the polar ice and so on (, Moon’s South Pole in NASA’s Landing Sites). The Moon is a place where we can make our first steps in sustainable living in space, within easy access of Earth for repairs, supplies, and emergency medvac back to Earth in only two days.

This compares evacuation times:

ISS emergency evacuation a few hours, resupply every few months < day to arrive

Moon emergency evacuation 2 days, resupply takes 2 days to reach the Moon

Mars emergency evacuation minimum 6 months, emergency resupply minimum 6 months to arrive

(added text to this infographic from the Canadian space agency: Distances between Earth and the International Space Station, the Moon and Mars - infographic)

Meanwhile, we can speed the Mars exploration so much that using this idea of "artificial real time" from computer games, we can control our rovers almost as easily as a rover on the Moon (say). So we can do a huge amount on Mars from Earth.

Video: Telexploration: How video game technologies can take NASA to the next level

All of this builds up assets on Mars that will be very useful if we do get a “pass” for human settlement after the biological survey of Mars.

The Mars colonization enthusiasts are so sure that the Martian biosphere will be safe for Earth. If they are right we will get a “pass” as a result of this exploration. It will hardly interrupt their plans at all if their confidence is well placed.

Once we get humans to Mars orbit - maybe not until late 2030s or 2040s we have the spectacular HERRO orbit for them to use. The ISS orbiting Earth is very inspiring, this would be too. It comes in close by both poles twice a day and it gets closest to Mars over the equatorial regions, the sunny side of Mars on opposite sides twice a day.

Video: One Orbit Flyby, Time 100x: Mars Molniya Orbit Telerobotic Exploration in HERRO Mission

Early astronaut explorers would likely use two spacecraft joined via tethers for artificial gravity to stay healthy, simulating mars gravity perhaps, and then operate surface marscopters, rovers and other surface assets, similarly to avatars in a computer game.

This is what it might look like from inside the spacecraft

Composite of photo from the Cupola of the ISS (Coleman, C, 2011) and Hubble photo of Mars (Hubble, 2003)

As our spacecraft get more capable (Conceptual design of in-space vehicles for human exploration of the outer planets) , humans can also explore and even colonize Callisto, outermost of the Galilean moons of Jupiter (High power MPD nuclear electric propulsion (NEP) for artificial gravity HOPE missions to Callisto) . This is far more suitable than Europa positioned right in the middle of Jupiter’s deadly ionizing radiation belts.

Elon Musk’s artist’s impression of his spacecraft for a crew of 100, the Interplanetary Transport System. He said his spacecraft would use Europa as a refueling stop in the outer solar system. Callisto is a far better refueling stop because of the lethal ionizing radiation around Europa which is within Jupiter’s radiation belts. The artist’s impression actually more closely resembles Callisto as the surface of Europa is probably broken up and rough on the meter scale, at least with current understanding (Interplanetary Transport System, Official ).

Inset shows artist’s impression of an exploration base on Callisto (, The Vision for Space Exploration : 22)

Them there’s Titan

Text on graphic: Later humans may colonize Titan - the only other location in our solar system with an atmosphere

  • in the Saturn system
  • thicker atmosphere than Earth (mainly nitrogen)

Titan's atmosphere is so thick:

  • humans don't need spacesuits - just very thick diving suits and bottled oxygen
  • habitats are as easy to construct as a terrestrial polytunnel
  • cold is far easier to protect against than vacuum
  • sources of energy from winds a few hundred meters up
  • gravity so low humans can fly by flapping wings!
  • sources for making plastics
  • ice for water, and for fuel
  • so very cold backward contamination is unlikely and forward contamination impossible unless it has liquid water in cryovolcanoes

(needs confirmation that there are no planetary protection issues)

(SpaceX Interplanetary Transport System at Saturn)

(Titan, Earth & Moon size comparison)

Finally over the centuries, and millennia, with space habitats slowly spinning for artificial gravity and large thin film mirrors to focus sunlight, we could explore and settle the entire solar system to Pluto and beyond (Space settlements: A design study: 175)

“At all distances out to the orbit of Pluto and beyond, it is possible to obtain Earth-normal solar intensity with a concentrating mirror whose mass is small compared to that of the habitat.”

[in space settlements spinning slowly for artificial gravity]

“At all distances out to the orbit of Pluto and beyond, it is possible to obtain Earth-normal solar intensity with a concentrating mirror whose mass is small compared to that of the habitat.”

Space settlements: A design study (1977)

[in space settlements spinning slowly for artificial gravity]

(Catalog Page for PIA21590 )

See:

Preprint with the literature survey, new planetary protection scenarios, recommendations and much more

Abstract:

In the late 2020s to 2030s, China, and NASA / ESA and Japan plan to return samples from Mars. We need to keep Earth’s biosphere safe from any Martian microbes.

Japan’s agency JAXA has the simplest mission, to return samples from the top few centimeters of Mars’s innermost moon Phobos. Any microbes in their samples already withstood ejection from Mars, most recently, 700,000 years ago. Once on Phobos, they were sterilized similarly to martian meteorites arriving at Earth today from that ancient impact. So JAXA doesn’t need to take any precautions.

JAXA warned this meteorite argument is not valid for samples from the Martian surface.

NASA’s draft EIS incorrectly says any life from Jezero crater can get here better protected and faster in a meteorite than in a sample tube. Martian surface dirt and dust can’t get here at all.

NASA’s EIS also proposes to contain its samples in a Biosafety Level 4 facility. However, the European Space Foundation sample return study in 2012 set size limits well beyond capabilities of a BSL-4 or indeed any current air filter technology.

We can avoid all these issues and keep Earth 100% safe by sterilizing samples before they get here, with the equivalent of a few hundred million years of Mars surface ionizing radiation. This has virtually no effect on geology, while terrestrial contamination in Perseverance’s samples makes most astrobiology impossible.

We can greatly increase science value with contamination free samples in a sterile container -returned to a martian gravity centrifuge in an unmanned satellite above GEO, to start Sagan’s “vigorous program of unmanned exobiology”.

This is a survey of central results in planetary protection literature, with new worst case scenarios such as mirror life, to encourage space agencies to ensure Earth’s biosphere is adequately protected when they return samples from Mars.

The preprint is here.

open letter to NASA | Planetary protection issues abstract | main points in open letter in more depth | finding an inspiring future | executive summary of preprint | this is like asking an architect to install a smoke detector | NASA's legal requirements under NEPA | About me

Author: Robert Walker, contact email robert@robertinventor.com