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

Main points in the open letter to NASA in more depth

The open letter went briefly through these points. You may well want more details, so here they are, with a focus on the conclusions relevant to NASA. The preprint goes into much more detail again with academic cites.

Section titles here are written like mini abstracts and summarize the main points and conclusions in the sections.

[note there is some overlap here with the executive summary of the preprint]

TITLES OF SECTIONS ARE LIKE MINI ABSTRACTS

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.

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) : pages 6 - 7)

NEED FOR BETTER COMMUNICATIONS WITH THE PUBLIC - ALL THIS IS TO GET NASA TO INSTALL A SMOKE DETECTOR TO PROTECT EARTH

I help people who get scared over the internet and it is very important for me that this is explained carefully and responsibly early on in all my communications.

• There is no way NASA can continue all the way through to 2033 without scrutiny by other agencies and the general public
• NASA’s plans to protect Earth will have to be very effective to pass this intense scrutiny.
• This open letter is to help to ensure that this scrutiny happens earlier rather than later - better for NASA, for the science return from the mission and for the public
• I have written this section and the open letter carefully to help prevent potentially future public anxiety and infodemic as we saw with the COVID pandemic.

John Rummel said:

Communications Unusual or unprecedented scientific activities are often subject to extreme scrutiny at both the scientific and political levels. Therefore, a communication plan must be developed as early as possible to ensure timely, and accurate dissemination of information to the public about the sample return mission, and to address concerns and perceptions about associated risks.

(A draft test protocol for detecting possible biohazards in Martian samples returned to Earth : 101)

The risk for this particular mission is likely very low as

• Perseverance is exploring a region with low likelihood of life
• even if it did return life the chance the first microbes returned from Mars would be harmful or even able to spread outside the laboratory is likely low.
• They may be as harmless as dandelions in the USA; most introduced species are harmless or even beneficial.

It is important as precedent to get this right and we do need to be careful from the get-go.

The smoke detector analogy helps. I got this from Margaret Race’s

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 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.

The EIS clearly hasn’t benefited from the use of experts in risk communication with the general public. As an example, the draft EIS gives this as one of the main questions from the public:

When the consequences of a failure are so great, a 100% guarantee should be required.

…

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),

NASA just say

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),

It is a reasonable and valid question. NASA don’t reply with a goal specification like 1 in 1000 or 1 in a million. Do they have any such target, and if so, what is it? We never find out.

Also it is factually incorrect. It would be more accurate to say:

“Some outcomes in science and engineering processes can’t be predicted with 100% certainty.”

We can predict that with 100% certainty that if we don’t return the samples there is no risk to Earth’s biosphere from them.

We can also achieve that certainty with sterilization of any samples that reach Earth.

There are many ways that NASA can achieve 100% safety for Earth’s biosphere and as public awareness increases, NASA will find there is far more awareness of this today than there was for the Apollo missions in the 1960s. Their plans will get intense scrutiny from the public, farmers, fishermen, doctors, nurses and experts in other agencies as the time approaches to return the samples from Mars.

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: 96)

For a more detailed response for scared people, please see my:

• Why I’m asking NASA to re-examine plans for its Mars sample return mission - like asking an architect to install a smoke detector - remote chance of house fire - but a house of billions of people - and at some point for sure they will have to do it

The most recent ESF Mars sample return study in 2012 made similar recommendations to earlier studies:

RECOMMENDATION 3

Potential risks from an MSR are characterised by their complexity, uncertainty and ambiguity, as defined by the International Risk Governance Committee’s risk governance framework. As a consequence, civil society, the key stakeholders, the scientific community and relevant agencies’ staff should be involved in the process of risk governance as soon as possible.

In this context, transparent communication covering the accountability, the benefits, the risks and the uncertainties related to an MSR is crucial throughout the whole process. Tools to effectively interact with individual groups should be developed (e.g. a risk map).

RECOMMENDATION 4

Potential negative consequences resulting from an unintended release could be borne by a larger set of countries than those involved in the programme. It is recommended that mechanisms and fora dedicated to ethical and social issues of the risks and benefits raised by an MSR are set up at the international level and are open to representatives of all countries

(Mars Sample Return backward contamination–Strategic advice and requirements : 59)

It is clear this hasn’t been done.

CARL SAGAN - “WE CANNOT TAKE EVEN A SMALL RISK WITH A BILLION LIVES” - HE WOULD CONTACT YOU IF ALIVE TODAY

I am a long-term admirer of NASA since before Apollo and my views on planetary protection are similar to those of Carl Sagan, one of my heroes.

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]

It’s strange to write this to you, but there doesn’t seem to be anyone in the public playing the role of Carl Sagan today. I am sure he would make a similar response to your EIS, though at an earlier stage, and he would have been listened to.

We will see that if this EIS goes ahead and NASA continue with their mission plans it is potentially hugely damaging for NASA’s reputation and also for science return even for this mission.

AS WITH SAGAN - THE MAIN CONCERN OF THE GENERAL PUBLIC IN THEIR COMMENTS ON THE EIS WAS RISK OF HARM TO HUMAN HEALTH AND EARTH’S ENVIRONMENT - 50 OUT OF 63 COMMENTS IN THE FINAL EIS

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.

• stop mission, unprecedented harm – test first – study in separate module attached to ISS – test first – stop mission
• stop mission – test first – test first, unprecedented harm – Study in space or not at all, keep Earth 100% safe, our efforts to contain the samples may seem lax a generation from now –test first
• stop mission – need clarity about security measures – off topic – alternative design - keep Earth 100% safe
• unprecedented harm – stop mission, unprecedented harm – alternative design – test first – test first
• test first – unprecedented harm – test first – Test first– Don’t return unless 100% safe – or sterilize first
• Don’t return – don’t return until 100% safe – test first – test first–test first
• ISS first – test first – test first – unknown risk, test first–sterilize first
• extra precautions for EES reentry - sterilize first – sterilize first – sterilize in space station first – sterilize first
• do not return – do not return – do not return – send to Russia first– issues with disinfection of earth entry site
• test first– support EIS– study in situ or space lab or sterilize first – fully support, suggests more samples – – off topic (future missions need to be designed for reeuse)
• multiple cautious measures – support EIS – support EIS– test or sterilize first – sterilize first
• test in situ or don’t return – do not return – unprecedented harm, test first – unprecedented harm, return to space station

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 quoting from an interview he did with Carl Woese when he was alive.

“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

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)

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),

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)

(Comment posted December 20th)

My own final comment, in 14 points ending:

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

. Comment posted December 20th

YOUR MAIN MISTAKES AND HOW THEY HAPPENED

With John Rummel and then Cassie Conley you had two world experts as planetary protection officers. They would be incapable of making these extremely serious mistakes in the EIS:

• EIS says “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)

• Objective 2.3 for Perseverance samples:
  “Modern biosignatures: Assess the possibility that any lifeforms detected are still alive or were recently alive.” (Planning implications related to sterilization-sensitive science investigations associated with Mars Sample Return (MSR) : table 2)

• 2.3B: Assess the possibility of metabolism and respiration
  (iMOST : 92)
• 2.3C: Assess the possibility that organisms within the sample are capable of reproduction in culture experiments.
  (iMOST : 93)
• Your cite for “existing credible evidence”: “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])
• EIS says “The natural delivery of Mars materials can provide better protection and faster transit than the current MSR mission concept. …. potential Mars microbes would be expected to survive ejection forces and pressure (National Academies of Sciences, Engineering, and Medicine and the European Science Foundation 2019),” (MSR DRAFT EIS 3–3)
• Your 2019 cite says “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 : 44-5. [use X to close splash])

Your 2019 cite also covers Mars sample return more briefly on page 5. There is a typo, “Mars” for “Phobos”. I don’t know if this could have contributed to the confusion? If so, again, Cassie Conley or John Rummel would have been incapable of such a mistake.

Text on graphic: NASA's citation for "potential Mars microbes would be expected to survive ejection forces and pressure" says "MSR material might come from sites that mechanically cannot survive ejection from Mars and thus any putative life-forms would de facto not be able to survive impact ejection and transport to space"

Your most recent peer-reviewed source on planetary protection for a Mars sample return is the National Research Council study from 2009. This also said it is not appropriate to use the meteorite argument for samples returned from Mars, in the section “Martian meteorites, Large-Scale effects and Planetary Protection”

“The potential hazards posed for Earth by viable organisms surviving in samples [are] significantly greater with a Mars sample return than if the same organisms were brought to Earth via impact-mediated ejection from Mars”

(Assessment of planetary protection requirements for Mars sample return missions : 47)

... Thus it is not appropriate to argue that the existence of martian meteorites on Earth negate the need to treat as potentially hazardous any samples returned from Mars by robotic spacecraft.

(Assessment of planetary protection requirements for Mars sample return missions : 48).

It was a remarkable discovery at the turn of the century that b. subtilis might be able to get from Mars to Earth on rare occasions.

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:

Whereas this harsh environment sets a definite barrier for most microorganisms known, some have developed survival strategies, by transforming into a dry state, the so-called anhydrobiosis ..., or by producing spores, the dormant state of certain bacteria … These characteristics make spores and anhydrobiotic bacteria especially prepared for coping with the extreme conditions of space

(Natural transfer of viable microbes in space: 1. From Mars to Earth and Earth to Mars : 401)

I give the example of swallows and starlings in my preprint. The barn swallow is not an invasive species as it was already here, because it can fly across the Atlantic. But the starling can’t cross the Atlantic and the Department of Agriculture estimates starlings cost the US economy $1 billion a year for agricultural damage alone.

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 don’t have many examples of invasive microbes on Earth because Earth is far more interconnected for microbes than for birds. But Didymo in the illustration is an invasive fresh water diatom in New Zealand. A few decades back the Great Lakes had many problems with non indigenous invasive diatoms that clogged up water treatment plants and caused bad smells in drinking water (Diatoms as non-native species)

Introductions can often be beneficial (The potential conservation value of non‐native species). But if a species can’t cross the Atlantic it has the potential to be invasive. In the same way if a Martian microbe can’t cross from Mars to Earth it has potential to be invasive here.

• Biological Safety Report says: “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)
• Tetanus kills thousands of newborns every year who miss out on vaccination (Tetanus), and is not adapted to an infectious lifestyle in any lifeform. Legionnaires disease is another example, a serious disease of the lungs often fatal that is only adapted to biofilms and freshwater protozoa - there are many other examples in the planetary protection literature (Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions)

These examples are all based on familiar life. We don’t know what we’ll find on Mars. Carl Sagan put it like this in 1973

"Precisely because Mars is an environment of great potential biological interest, it is possible that on Mars there are pathogens, organisms which, if transported to the terrestrial environment, might do enormous biological damage - a Martian plague, the twist in the plot of H. G. Wells' War of the Worlds, but in reverse. … The chance of such an infection may be very small, but the hazards, if it occurs, are certainly very high.

(The Cosmic Connection – an Extraterrestrial Perspective : 162)

• Biological Safety Report says: “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)
• NASA’s own citation, Merino et al., includes a remarkable exception, Planococcus Halocryophilus: temperature range at least -15 °C to 37 °C. Optimal growth at 25°C. Showed metabolic activity down to -25°C, the lowest temperature tested and may grow at very low temperatures too slowly to test in the laboratory) (Living at the extremes: extremophiles and the limits of life in a planetary context: table 3) Was isolated from Canadian permafrost at -16°C (Planococcus halocryophilus sp. nov., an extreme sub-zero species from high Arctic permafrost).

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)

• Many terrestrial organisms do well in Mars simulation chambers: (Habitability of Mars: How Welcoming Are the Surface and Subsurface to Life on the Red Planet?).
• Chroococcidiopsis, a highly resilient blue-green algae does well in Mars simulation chambers (… Chroococcidiopsis sp. Exposed To a Mars-Like Near Space Environment).
• It can find all its nutritional requirements in seawater, or rocks such as basalt, so long as it also has access to water and a source of energy such as sunlight.
• This blue-green algae could live anywhere on Mars with basalt and access to water. Strains of it can live almost anywhere on Earth, in rocks, sea water, even 10 to 750 meters below the Atlantic sea bed using an alternative metabolic pathway to metabolize hydrogen and with nothing else except gabbro to live on (Recycling and metabolic flexibility dictate life in the lower oceanic crust).

The NRC 2009 sample return study said the potential for even large-scale negative effects on Earth’s inhabitants or environments appears to be low but is not demonstrably zero

“The committee found that the potential for large-scale negative effects on Earth’s inhabitants or environments by a returned martian life form appears to be low, but is not demonstrably zero”

(Assessment of planetary protection requirements for Mars sample return missions : page 48).

THESE MISTAKES ARE EXTREMELY SERIOUS BECAUSE THEY REINFORCE FALSE REASONING IN THE SPACE COMMUNITY AND COULD LEAD TO PRIVATE SPACE AND OTHER AGENCIES DROPPING ALL PROTECTION OF EARTH AND 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 this EIS is approved other agencies and private space will be strongly encouraged to argue, in good faith but mistakenly that:

• (PLAUSIBLE BUT INVALID) Mars must be uninhabitable,
• (PLAUSIBLE BUT INVALID) If there is life on Mars it must have got here already
• (PLAUSIBLE BUT INVALID) If there is life on Mars, it is harmless to humans,
• (PLAUSIBLE BUT INVALID) Anyway, if there is life on Mars, it can’t survive on Earth,

NASA says so!

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 from Earth’s biosphere.

There is no reason to suppose any direct influence, but these three arguments are also widely believed by Mars colonization enthusiasts. The president of the Mars Society, Robert Zubrin presented them first in a non-peer-reviewed op. ed. in the Planetary Report: ("Contamination From Mars: No Threat").

Robert Zubrin’s op. ed. got an immediate reply from planetary protection experts:

• A Case for Caution by John Rummel, NASA'S planetary protection officer at the time, and previously, NASA senior scientist for Astrobiology
• Hazardous Until Proven Otherwise, by Margaret Race, a biologist working on planetary protection and Mars sample return for the SETI Institute and specialist in environmental impact analysis
• Practical Safe Science by Kenneth Nealson, Director of the Center of Life Detection at NASA's JPL at the time.

("Opinion: No Threat? No Way")

However, many continue to believe his arguments to be valid as Mars colonization enthusiasts are usually aware only of Robert Zubrin’s arguments and not the rebuttals.

These false reasons seem plausible probably because of science fiction amongst other reasons. Carl Sagan when talking about the risk of pathogens of humans from Mars had to talk about:

the twist in the plot of H. G. Wells' War of the Worlds, but in reverse. (The Cosmic Connection – an Extraterrestrial Perspective : 162)

There are numerous encounters with alien life on Mars in science fiction. But the only one where microbes cause harm that I know of is the one where Martians invade Earth and are harmed by our microbes. Carl Sagan clearly also only knew of a story in that direction.

There is no reason particularly why Martian life should be more vulnerable to terrestrial microbes than vice-versa. It’s just that it’s never been used as a plot twist in the other direction at least in well known science fiction stories.

It is very damaging for NASA’s reputation for planetary protection to reinforce this false reasoning in the EIS. It’s especially damaging after its planetary protection experts have worked so vigorously to counter this false reasoning in the past.

But now I understand better how it happened. I found out that first, sadly, you closed the interagency panel in 2006, which only operated from 2000 to 2005 (Review and Assessment of Planetary Protection Policy Development Processes : page 26), and closed your planetary protection office in 2017, and appointed a new “planetary protection officer” in your Office of Safety and Mission Assurance (With planetary protection office up for grabs, scientists rail against limits to Mars exploration) with no independence from NASA.

PPAC, the interagency panel which you disbanded in 2006 had representatives from:

• Department of Agriculture,
• Department of Health and Human Services,
• National. Institutes of Health
• Centers for Disease Control and Prevention
• Environmental Protection Agency,
• Department of the Interior
• National Science Foundation
• Department of Transportation
• Federal Aviation Administration
• Executive Office of the President

It also had international representatives from other space agencies such as:

• European Space Agency
• Japan Aerospace Exploration Agency

List of agencies from: (Review and Assessment of Planetary Protection Policy Development Processes : page 26) supplemented by (The Goals, Rationales, and Definition of Planetary Protection: Interim Report : page 37)

So you have closed down all internal or external genuinely independent peer review. Meanwhile nearly all of the authors with expertise in this area are closely connected with NASA and can’t say much.

This leaves the NEPA process of public comments is the only remaining level of peer review you have. One of your employees, Chester Everline took the unusual step of issuing a public comment critical of the EIS on the last day of public comments - he is one of your principal authors of your handbook on probabilistic risk assessment (Probabilistic risk assessment procedures guide for NASA managers and practitioners). He found a lack of clarity in the risk assessment and wrote:

Chester Everline: 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

…

If the MSR Campaign can convincingly demonstrate that material returned to Earth by MSR will be subjected to more severe conditions than those transported by natural processes, then MSR poses no greater risk to Earth than we would expect from the next Mars meteorite.

However, if this cannot be convincingly demonstrated [IT CAN’T AS WE SAW] the MSR Campaign should seriously consider not returning samples using the technology described in the PEIS (i.e., transition to a deferred return campaign option).

(Comment posted December 20th)

I sent him an email to ask if we could liase but it was no surprise when he said as a NASA employee he can’t engage. We know the views of the previous planetary protection officers. Cassie Conley, former NASA planetary protection officer from 2006 - 2018:

“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

(Dr. Catharine Conley) [for her dates as NASA planetary protection officer]

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

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)

(Curriculum Vitae John D. Rummel) [for his dates as NASA planetary protection officer]

But like Chester Everline, as former NASA planetary protection officers, they wouldn’t be able to liase with me.

It seems to be left to me for now. At the time, I was in the middle of my first paper on astrobiology, on planetary protection for NASA’s Mars sample return mission. So, I pivoted to this critical assessment of your EIS.

NASA is usually so reliable in science. But we see impacts of these decisions all through your current EIS. It is far from world-leading. Indeed, the EIS shows no awareness of established results repeated in every study on backward contamination of Earth by martian life to date as we have just seen.

The Space Studies Board which has done many planetary protection reviews finds they need to educate committee members unfamiliar with basic planetary protection concepts.

A typical committee consists of only two or three individuals with direct experience of the issue to be addressed … 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 : Page 77)

We see how pioneering the work of Sagan and Lederberg was, the work of remarkable minds. Without that background, it’s no wonder there are so many mistakes in the EIS.

YOUR FOURTH MAJOR ERROR - NOT ALLOWING FOR DEGRADATION DUE TO IONIZING RADIATION AND HIGH LEVELS OF FORWARDS CONTAMINATION BY TERRESTRIAL LIFE

Rummel refers to issues with forward contamination of the samples as a potential “train wreck”.

If the issues aren't resolved, Rummel says, the rover could be headed for a bureaucratic "train wreck".

(With planetary protection office up for grabs, scientists rail against limits to Mars exploration)

This leads to your fourth major error. Cassie Conley or John Rummel would be incapable of this mistake too, that you didn’t allow for the degradation of surface organics on Mars by ionizing radiation for rocks with even a young exposure age.

What will happen to public and scientific opinion in 2033 if this continues? They will find out that

• NASA hasn’t prepared scientifically credible plans to protect Earth and
• the samples they return will be valueless for the past life searches (and probably for present-day life too) because of the
• 8.1 ppb forward contamination by terrestrial organics, 0.7 per biosignature
  (Mars 2020: mission, science objectives and build : table 6)
• ≪ 0.1 ppb of recognizable past organics in even recently exposed surface organics on Mars after degradation by ionizing radiation as 100 ppb is reduced to 0.1 ppb in only 70 million years in the best case (just silica and no water or perchlorates).
  
  That compares with 80 million years for the youngest measured exposure age for the Curiosity samples and Perseverance can’t measure exposure ages.
  
  Some Perseverance rocks may well have 100 ppb of organics, but nearly all of that will be broken up and modified by ionizing radiation, and the oxidizing effects of the activated silica, to the extent that the original structure of the molecules is unrecognizable.
  
  For clays with water incorporated as well as silica the process is faster with only 30 million years to reduce 1000 fold (10 fold reduction every 10 million years).
  (Rapid Radiolytic Degradation of Amino Acids in the Martian Shallow Subsurface: Implications for the Search for Extinct Life : 112)

John Rummel’s metaphor of a “train wreck” lead me to the metaphor of a ship wreck and the Titanic that I mentioned above, and I did this graphic for it for the detailed executive summary.

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 )

WE CAN FIX THIS BUT HAVE TO MOVE AWAY FROM NASA’S CURRENT ASSUMPTION THAT MARS WILL BE SAFE FOR HUMANS AND OUR PRIORITY IS TO PREPARE FOR HUMANS ON MARS - THERE IS A REASON WHY OTHER AGENCIES CAN’T SUPPORT THIS

But we can fix this! I have many specific suggestions here that can turn this from a bureaucratic “train wreck” to an approach that returns NASA to its leading role in science and planetary protection.

First, we have to move away from NASA’s current assumption that Mars will be safe for humans, and that we have to prepare to send humans there as fast as possible as our top priority. This is your current policy as explained by your current Planetary Protection Engineer.

“There’s still a lot of work to go as we start to pave the way to humans on Mars — we’ve never done that, it’s a new precedent, so we’ll need that continued support to help with managing those knowledge gaps, including management support, engineering support and of course funding support. The rubber is hitting the road; it’s time to get it done and we need that collective agency support to do that.

(SMA Leadership Profile: Nick Benardini)

There is a reason why NASA isn’t getting that collective agency support to rush forward to send humans to Mars as fast as possible. We can’t assume we have a scenario with no life on Mars or one where all life on Mars is safe for humans. Your own iMOST team said:

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

(iMOST : page 88)

SCENARIO OF MIRROR LIFE SHOWS IT MIGHT NEVER BE SAFE TO RETURN SAMPLES FROM MARS

To motivate this I will look at:

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.

• Scenario of mirror life - a mirror life blue-green algae which can live anywhere where it has access to water, sunlight, and basalt or other rock with all the trace elements it needs (or sea water), evolved independently from mirror chemicals.
• In this scenario, the mirror life is likely to be adapted to use normal organics because of infall from space, but few terrestrial microbes have the enzymes to convert mirror to normal organics to metabolize it. We won’t want to find out what happens if mirror life spreads through our planet converting normal to mirror organics that only mirror life can use.
• Terrestrial life might well still eat mirror organics, like artificial sweeteners, but starve in the midst of plenty because it couldn’t do anything with the flipped starches or proteins, and many fats would also be inaccessible (An adventure in stereochemistry: Alice in mirror image land)

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

• Chroococcidiopsis, a highly resilient blue-green algae does well in Mars simulation chambers (… Chroococcidiopsis sp. Exposed To a Mars-Like Near Space Environment).
• It can find all its nutritional requirements in seawater, or rocks such as basalt, so long as it also has access to water and a source of energy such as sunlight.
• This blue-green algae could live anywhere on Mars with basalt and access to water. Strains of it can live almost anywhere on Earth, in rocks, sea water, even 10 to 750 meters below the Atlantic sea bed using an alternative metabolic pathway to metabolize hydrogen and with nothing else except gabbro to live on (Recycling and metabolic flexibility dictate life in the lower oceanic crust).
• Chroococcidiopsis is an ancient polyextremophile with numerous alternative metabolic pathways that strains of this genus can use, including nitrogen fixation, methanotrophy, sulfate reduction, nitrate reduction etc (Metabolic pathways – Chroococcidiopsis thermalis). An alien microbe from Mars based on mirror life might be just as versatile, accumulating many pathways over billions of years of evolution on Mars. That would help it to radiate through our biosphere even if we return only one species from 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.

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).

The two Viking landers remain the only spacecraft to attempt life detection in situ on Mars. Some experts predict independently evolved life in our solar system and elsewhere could be mirror life. Here chiral means it comes in two mirror forms like your left and right hands.

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

(Punctuated chirality : 7)

They also predict there is likely as much mirror life as ordinary life in the universe. Here racemic means equal amounts of the normal and mirror forms:

As a consequence, a statistically large sampling of extraterrestrial stereochemistry would be necessarily racemic on average (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.

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.

Some synthetic biologists have embarked on a likely decades-long research project to make mirror life in the laboratory by slowly flipping components of a terrestrial microbe bit by bit.

Synthetic biologists will ensure mirror life is not able to survive in the wild at any point in this slow step by step transformation from normal to mirror life. In Kasting and Church’s worst-case scenario for release of mirror life from a terrestrial lab, mirror life retains the edge over normal life in this evolutionary race and eventually there is little left except mirror organics and life that can use it. They suggest humans could go extinct in this worst case scenario that they need to avoid, at least in natural ecosystems

“—both Kasting and Church think mirror predators would evolve, but whatever life existed on Earth by that point wouldn’t include us.”

(Mirror-image cells could transform science-or kill us all)

It would be a similar scenario if we return naturally evolved mirror life from another planet.

I don’t think we’d go extinct in that scenario. We might be able to engineer terrestrial microbes with the ability to eat mirror organics and limit the mirror life, and in the worst case we could “paraterraform Earth” - we could cover jungles, grassland, mountains, islands, coral reefs, eventually continents, ice sheets, and large areas of the oceans with larger and larger shelters like Biosphere 2 (Under the Glass Systems) and with the technology of the future, manage them internally to keep out most of the mirror life. But if we do have mirror life on Mars, we as a civilization would surely decide not to do the experiment of returning it to Earth.

NASA needs to plan in a more flexible way where we have a future that is inspiring and encourages space exploration and settlement for BOTH scenarios,

• a future (such as no life or mutually benign life on Mars) where humans CAN SAFELY explore the surface of Mars in person
• a future with limited quarantine and other measures for travel between the planets to keep out certain invasive species that would harm Earth’s biosphere, humans, or agriculture
• a future (such as mirror life on Mars) where it is NEVER SAFE for humans to explore Mars in person - or at least, never return to Earth after doing so

We need to look at this with clear eyes. The reason we have to do planetary protection is because we don’t know which of those two scenarios we have on Mars.

SCENARIO OF A NEW FUNGAL GENUS TO REINFORCE CARL SAGAN’S MESSAGE THAT WE CAN’T BE SURE MARTIAN LIFE IS SAFE FOR HUMAN HEALTH

I have developed many other scenarios to help guide the decision processes for a Mars sample return.

I developed a plausible scenario for a very serious human pathogen to motivate taking great care to protect human health from large-scale impacts.

• a fungal disease, similar to Aspergillus, which is not adapted to humans and has severe effects on 200,000 immunocompromised people a year, fatality rate 30% to 95% (Hidden killers: human fungal infections), and in immunocompetent people, it causes allergic asthma in 4.8 million a year, 2.5% of all asthma cases, which in 400,000 cases progress to the serious chronic disease of chronic pulmonary aspergillosis (Global burden of allergic bronchopulmonary aspergillosis with asthma and its complication chronic pulmonary aspergillosis in adults)
• Aspergillus fumigatus (main pathogen of humans) has no known specific adaptations to infect any other organism, human or otherwise (Aspergillus fumigatus: contours of an opportunistic human pathogen). Instead it infects us because of many adaptations to extreme environments (Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species)
• with characteristics that may well be shared by martian fungi (Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species).
• Our immune system has specific adaptations to Aspergillus to recognize it relying on pattern matching to recognize distinctive features specific to the aspergillus genus (Antifungal immune responses: emerging host–pathogen interactions and translational implications : table 1),
• Our immune system also has specific adaptations to the Aspergillus genus to dampen down potential allergic responses (The multifaceted role of T-helper responses in host defense against Aspergillus fumigatus).
• A novel genus from Mars might not fit any of the patterns for fungi that infect humans and be invisible to the immune system of some or all of us, and / or some or all might have severe allergic reactions.
• A novel genus from Mars might fit some of the patterns so our body reacts but without the finely calibrated responses it has for recognized fungi - and trigger severe allergic reactions or a progressive allergic lung disease in some or all of us,
• Fungal diseases like aspergillosis are hard to diagnose, similar to other serious conditions, and treatment often starts late for that reason (Hidden killers: human fungal infections. )
• We have very few antifungals and a new genus from Mars might be naturally resistant (Mechanisms of antifungal drug resistance). Most antibiotics don’t work with fungi because they are evolutionary too close to us, as eukaryotes (cells with a nucleus) A new fungal genus might be naturally resilient, similarly to azole resistant aspergillus or more so (Antimicrobial-Resistant Aspergillus)
• We could expect a massive increase in research into targeted antifungals for a new fungal genus from Mars, as for the vaccines for COVID, with public funding. But in a worst case scenario, for the first few months to years, we might have no way to treat a novel fungal disease from Mars.

Text on graphic: Aspergillus diseases are hard to diagnose as they resemble other conditions like TB and we often have harmless colonization.

Diseases due to a novel fungal genus from Mars may be similarly hard to diagnose, and it might be naturally resilient to our antifungals.

Graphic from: (Pulmonary Aspergillosis: An Evolving Challenge for Diagnosis and Treatment - Infectious Diseases and Therapy : figure 1)

See also Mayo clinic overview: (Aspergillosis - Diagnosis and treatment - Mayo Clinic )

SCENARIO OF A NOVEL FUNGAL GENUS LIKE ASPERGILLUS ALSO HIGHLIGHTS POTENTIAL IMPACTS OF INTRODUCED MARTIAN ORGANISMS ON BIRDS AND OTHER WILDLIFE

The example of aspergillus also highlights the issue that opportunistic fungal pathogens will affect other animals not only humans. Birds particularly are often affected by aspergillus leading to large die-offs. The worst affected are waterfowl, raptors and gulls, and they often get it as a result of eating mouldy waste in agricultural fields. (Cornell Wildlife Health Lab). It is also a serious disease in birds kept in captivity, with some especially vulnerable such as penguins, raptors or turkeys.

I will summarize some of the main points in (Aspergillosis in mammals and birds: impact on veterinary medicine):

Aspergillus infections are rare in mammals but it does affect:

• dogs, horses, and rarely, cows and dolphins

However birds are especially affected by Aspergillus. This is because of features of their anatomy that might also make them especially vulnerable to a novel fungal genus from Mars.

• No epiglottis to prevent particulate matter from entering the lower respiratory tract
• No diaphragm, so they can’t produce a strong cough reflex.
• Fewer beating cilia (finger -like protrusions) to move particles out of the lungs

Their immune system also isn’t as well adapted to kill Aspergillus as the human immune system.

It is a major cause of death in birds whether in the wild or in captivity and whether young, mature or geriatric. As with humans it affects birds whether they are immunocompetent or immunosuppressed.

Some species are particularly vulnerable:

• turkeys, penguins, raptors and wildfowl.

As with humans the air quality matters, and if they are kept indoors with limited air exchange, and aerosolized toxins that irritate the mucosal membranes and temperature and humidity not suitable for them.

For details see: (Aspergillosis in mammals and birds: impact on veterinary medicine).

There are many other potential worst-case scenarios which I cover in the preprint.

THE GNARLY QUESTION OF OUR VULNERABILITY TO A COMPLETELY ALIEN BIOLOGY

Some of the work I did was to make a first start at the gnarly question of our vulnerability or otherwise to a completely alien biology. All the example pathogens of humans that I found in the planetary protection literature are based on familiar life. What we find on Mars may not be related to terrestrial biology and this has had little attention in the literature.

I did find some speculative ideas about the effects of a completely alien biology. Some astrobiologists have said there is a possibility that more generally, in a worst case scenario, we might all be in effect immunocompromised to an unfamiliar exobiology from Mars.

This suggested the topic needs further attention. Just as we needed to look at the effect of mirror life on our biosphere, we also need to consider the potential for a completely alien opportunistic infection of humans and terrestrial organisms.

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)

In that paper he looked at the dilemma of a parasite that risks killing its host if it proliferates too fast, and few parasites benefit from the death of the host, but if it proliferates too slowly it risks being overwhelmed by its host’s immune system within a week to 10 days unless it can develop stealth tactics to continue to evade it after that. Pathogens find a balance between killing its host and being overwhelmed.

But a microorganism from Mars hasn’t been through this process. He looked briefly at how our defences against pathogens work. He found they might not recognize an alien lifeform, though it’s also possible an alien lifeform might not recognize us as something to infect.

Lederberg wrote two papers on this topic, the other is: (Parasites face a perpetual dilemma).

These ideas have had little attention in the planetary protection literature since Lederberg’s two papers in the 1990s.

The 2009 NRC Mars Sample Return study doesn’t cite or mention Lederberg, see search results. The ESF study in 2012 does cite one of the papers (Parasites face a perpetual dilemma)but adds nothing new to the discussion. and concludes (Mars Sample Return backward contamination – Strategic advice and requirements : 12)

With those thoughts in mind, it may seem that the risk posed by returning a dangerous biological entity (e.g. a virus-type, microorganism, etc.) is quite low. Nevertheless, it still cannot be guaranteed to be impossible.

However Joshua Lederberg himself doesn’t go so far as to say the thinks the chance we can be harmed by a totally alien parasite is low. He doesn’t venture an opinion. He just points out the issue.

It is hard to make progress on this topic without examples of alien life. However I did find some potential for a future Mars sample return review to take it further.

I found three methods that could be explored to find out more about this topic.

First, I use the analogy of Aspergillus. As we saw, the main pathogen of humans, Aspergillus Fumigatus, is not adapted to avoid our immune system or to co-opt the body’s cell processes like viruses or other pathogens. It just attacks our bodies as it would anything else containing desirable organics. For this to work, the alien parasite needs to:

• be able to recognize terrestrial organics as edible
• be able to use terrestrial organics
• be resilient to the stresses it finds in a human body
• have filaments strong enough to penetrate the barriers such as skin, or cell wall, of terrestrial organisms.

If we look at the specific adaptations of Aspergillus to extreme environments that make it such a successful pioneer pathogen in humans, these could potentially be shared by alien microbes from Mars even from an unfamiliar biology not related to terrestrial life.

• Can recover and rehydrate rapidly from desiccation – this lets inhaled desiccated spores recover rapidly to colonize the respiratory tract
• Able to protect its cell membranes from breakdown (lysis) by the immune system (Aspergillus does this using large amounts of melanin)
• Produce enzymes that break down proteins (proteases)
• Produce branching filaments (hyphae) which mechanically penetrate tissues and can also break up into fragments that can spread rapidly through immunocomromised patients
• Able to colonize a wide range of media, highly efficient at taking up nutrients and converting it to energy
• Amongst the most stress tolerant of species, (table 2),
• Able to protect themselves from agents that speed up reactions (chaotropic agents) like urea and ethanol, [there are many chaotropic agents on Mars such as the perchlorates]
• Able to tolerate low oxygen levels in the lungs (as low as 1% partial pressure in inflamed tissue) [table 2)
• able to produce various chemicals to protect themselves from the environment around them. (table 2)
• Naturally resistant to antifungals using various mechanisms that an alien microbe might also be able to use (table 1)

(Ecology of aspergillosis: insights into the pathogenic potency of Aspergillus fumigatus and some other Aspergillus species)

For this infection to be effective, terrestrial organisms must

• be unable to recognize the alien fungal analogue, or
• be unable to stop it from penetrating the organism and extracting enough useful organics to continue its life cycle

Alternatively for it to be problematical, terrestrial organisms must

• overreact with an allergic reaction to any attempt to attack them by alien life.

In the forward direction, the physicist Claudius Gros looks at a clash of interpenetrating biospheres in his paper on a "Genesis project" to develop ecospheres on transiently habitable planets. Gros reasons that the key to functioning of the immune system of multicellular organisms, plants or animals, is recognition of “non-self”. He presumes that biological defense mechanisms evolve only when the threat is actually present and they don’t evolve to respond to a never encountered theoretical possibility (. Developing ecospheres on transiently habitable planets: the genesis project. ).

“How likely is it then, that ‘non-self’ recognition will work also for alien microbes?"

"Here we presume, that general evolutionary principles hold. Namely, that biological defense mechanisms evolve only when the threat is actually present and not just a theoretical possibility. Under this assumption the outlook for two clashing complex biospheres becomes quite dire.".

As with the issues we already saw with a novel fungal genus, an alien microbe might find no defences. I have a look at this in more detail in my preprint. This is just a brief summary of some of the main points.

I looked at the natural antibiotics, which are our body’s first defences against pathogens, and whether they could recognize “non self” faced with an alien biology. Many of these are peptides, short sections of proteins that can interfere with the functioning of pathogens to stop an infection.

Some of the natural antibiotics are targeted to specific genera of terrestrial life (The applied anatomy of human skin: a model for regeneration : table 1) . These are not likely to work with an alien biology. But others target cell walls in such a general way they might work even with an alien biology (Antimicrobial and host-©defense peptides as new anti-infective therapeutic strategies)

These broadspectrum natural antibiotics rely on negatively charged outermost acid groups in bacterial cell walls (the cells are positively charged inside) and then use molecules that are water attracting at one end and water repelling at the other end to bridge into the center of the cell wall and then across it similarly to the lipid bilayer that makes up the cell wall, and so are able to construct a breach in the cell wall. There are various ideas for how this might work (The antimicrobial peptides and their potential clinical applications : Fig 3).

The recognition of non self is simple here, eukaryote cells are made up of neutrally charged lipids “uncharged neutral phospholipids, sphingomyelins and cholesterol” (The antimicrobial peptides and their potential clinical applications) and so aren’t affected.

This simple form of recognition of non self is rather general and it would work with any alien biology with negatively charged cells and with a similar size and structure of lipid bylayer to ensure that the peptide can bridge the gap successfully between the inside and the outside of the cell.

However, this is a rather crude recognition of non self. It is unable to recognise fungi as “non self” because fungi also have neutrally charged lipids.

Graphical summary:

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)

So this method wouldn’t work with an independently evolved alien fungal analogue might well happen to have cell membranes that are made up of neutrally charged lipids. It doesn’t need to be closely related to terrestrial life to do that, and this would make the alien life, too, immune to these natural broad spectrum antimicrobials.

The way fungal infections work is very general. An alien analogue could act similarly to this, insert filaments into a terrestrial host, in this case, diatoms, to extract organics for its won use, and in the process kill the host.

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)

If we did return an alien microbe that penetrated cells and organisms with filaments like fungi, and which has a neutrally charged cell wall, it might well be that we have no natural defences in our immune system. We’d then need to look at therapeutics to protect ourselves.

We might be able to develop drugs to target the alien biochemistry. However that might take longer than drugs to treat terrestrial pathogens because first we’d have to understand how the alien biochemistry works, which might take some time. There is some work on broad spectrum antifungals, similarly to our natural broad spectrum antimicrobial peptides.

Perhaps something similar would work for alien biology. The challenge, as for their use against terrestrial microbes, is to provide them in a way that avoids harming the host (Antimicrobial and host-©defense peptides as new anti-infective therapeutic strategies). Could we develop an analogue of the peptides that recognizes some feature of the alien biology and uses that to distinguish it from the neutrally charged eukaryotes?

Then we would also have the issue that the alien fungal analogue might attack terrestrial eukaryotes more generally. If it is able to attack humans, it’s not likely to be specific to us. So would we have to develop therapeutics to protect our cows, parrots, blue whales etc too? How could we administer them?

This example suggests a mixed picture. Some of our immune system’s recognition of “non self” might continue to work for some forms of alien life. But some forms of alien life might not be recognized by our immune system at all, if they happen to have accidental resemblances to features of terrestrial biology.

I also looked at fungal pathogens of blue-green algae. We likely have no reason to be concerned about viruses of alien microbes similar to baceriophages. They would be adapted to hijack the cell machinery of an alien biology and are not likely to be able to attack our microbes.

However in the last few years researchers have found numerous fungal pathogens of microbes. This was a surprise discovery.

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).

Stages of infection of a freshwater cyanobacteria Anabaena macrospora by two species of chytrid fungi.

This is a discovery too recent to be covered in the 2009 Mars sample return study.

Fungal dark matter was discovered as a result of rapid gene sequencing, first as parasites of fresh water phytoplankton.

Scientists are now finding many fungal parasites of marine microbes too and call them "A mystery yet to unravel".

Terrestrial phytoplankton might have no defences against a novel fungal pathogen of Martian cyanobacteria.

Suggestion: pathogens of an unrelated alien biology might also be able to infect terrestrial microbes in a similar way.

Scanning electron micrograph of possible chytrid fungi infecting diatoms

The main graphic is from here: (Fungal Parasitism: Life Cycle, Dynamics and Impact on Cyanobacterial Blooms : Figure 7)

The scanning electron microscope photo is from here, putative chytrid fungi coloured in pink false colour: (Chytrid fungi distribution and co-occurrence with diatoms correlate with sea ice melt in the Arctic Ocean - Communications Biology : Fig 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)

Microbes from Mars might be infected with fungal pathogens which could already be adapted to infect other microbes. Many of these diseases are chytrids (Basal parasitic fungi in marine food webs—a mystery yet to unravel)., This class of fungi is best known for the amphibian fungal disease chytridiomycosis which is caused by the fungus (Batrachochytrium dendrobatidis), which had severe effects on many amphibian species around the world (., chytridiomycosis ). However it is also one of the main classes of fungi that attack microbes.

Chytrids have a fossil record that goes back half a billion years and are the simplest of the fungi (Characteristics of Phylum Chytridiomycota). They are the only fungi with zoospores (“baby” fungi) that can swim to find a new host to infect using hair-like flagella to propel themselves. Some chytrid species live on dead organics, others are parasites of algae, microscopic worms, plants and amphibians. Some are useful in ecosystems because of the way they can break up cellulose, chitin and keratin (Characteristics of Phylum Chytridiomycota).

Since Mars could have analogues of our blue-green algae (cyanobacteria), it’s reasonable to take the example of fungal infections of terrestrial blue-green algae. Cyanobacteria (blue-green algae) defend themselves from chytrid fungi similarly to the way the human immune system defends us from fungi, using peptides specific to this genus of fungi. The antifungals they use against chytrids are microcystins, microviridins, or anabaenopeptins.

In one study, researchers used genetic engineering to knock out the capability of a strain of the cyanobacteria Planktothrix to make these antifungals. When they did this, the cyanobacteria lost its resilience to the fungi. . In one example the wild type cyanobacteria were completely immune to one of the chytrid strains they studied while it could infect all the cyanobacteria mutants even with just one of these classes of antifungals removed (. Putative antiparasite defensive system involving ribosomal and nonribosomal oligopeptides in cyanobacteria of the genus Planktothrix. ). So the cyanobacteria seem to need all three types of antifungal for protection against chytrids.

This suggests terrestrial blue-green algae might initially have no defences against a novel fungal disease of their analogues on Mars.

More generally this suggests a possibility that Claudius Gros’s issue with recognition of non self may extend to pathogens of microbes and not just higher life.

With the very rapid evolution of microbes we can expect them to develop defences rapidly. However this analogy would seem to suggest that initially they might have no defences against a novel fungal pathogen of an alien biology, in the worst case.

It does also suggest the possibility of fungal pathogens of our blue-green algae in the case where Mars has life related to terrestrial life.

Second, I looked at the possibility of an alien microbe that has no interest in terrestrial organics - doesn’t recognize it or can’t use it - for this I used the analogue of nanoplastics and microplastics

We don’t have enough microplastics or nanoplastics in our bodies to cause serious harm. But if at some point our biosphere got mixed with an alien biology to the extent that half the microbes in the environment are an alien biology, or even a small percentage like a tenth of a percent or a thousandth of a percent, we might have large amounts of alien microbes in the environment, far more than for microplastics or nanoplastics (submicron microplastics are called nanoplastics).

Our bodies are to some extent permeable to small particles that our immune system ignores. At 10 microns or less in diameter, they can potentially cross into the blood stream through the submicron barrier in the lungs. At 0.1 microns or less they can penetrate to the blood stream directly through our skin. Once in the blood they can access all organs of the body (A detailed review study on potential effects of microplastics and additives of concern on human health).

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)

We don’t get enough blood clots from microplastics and nanoplastics to be a concern. But this analogy suggests that if some time in the future Earth’s environment is filled with large numbers of alien microbes we might get significant levels of blood clots from them in our blood.

These coronas can also pick up fragments of pathogens. The immune system can respond to those with antibodies and try to get rid of the microplastics as if they were pathogens, which leads to sterile inflamation. I.e. inflamation triggered by something harmless.

We might also get sterile inflammation responses to alien life even if it doesn’t have a blood corona. This is similar to the sterile inflammation of gout (responding to harmless urea crystals) or silicosis (responding to harmless silica particles). (Impacts of microplastics on immunity).

More generally, as with the allergic reactions to Aspergillus, we might be allergic to harmless alien microbes. These allergic reactions might sometimes be serious.

Third, I explore the possibility of terrestrial biology misincorporating amino acids from an alien biology based on the example of BMAA. which is produced, for instance, by one strain of Chroococcidiopsis, chroococcidiopsis indica (Diverse taxa of cyanobacteria produce β-N-methylamino-L-alanine, a neurotoxic amino acid)

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.

Kenneth Rodgers, Matthew Ray/EHP (The emerging science of BMAA: do cyanobacteria contribute to neurodegenerative disease?).

This leads to protein misfolding and these misfolded proteins have been found in nerve cells of people with ALS (The emerging science of BMAA: do cyanobacteria contribute to neurodegenerative disease?)..

This leads to interesting questions about what the effects might be of an extraterrestrial biology not based on terrestrial amino acids? An extraterrestrial biology could have proteins built up of many more amino acids than the 20 encoded in RNA and used to build proteins in terrestrial biology.

There are 140 amimo acids that occur elsewhere in terrestrial biology, but not in proteins (Natural expansion of the genetic code). A computer search turned up nearly 4,000 biologically reasonable amino acids (Mapping Amino Acids to Understand Life's Origins). Many of those won’t occur in nature, but terrestrial biology also includes non natural amino acids. Meanwhile also many of the natural amino acids don’t occur in terrestrial biology and might potentially be used in extraterrestrial biology. 52 amino acids have been found in the Murchison meteorite (Amino acids in meteorites)

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

Proteobacteria in our gut may provide some protection against BMAA by removing it (Murky Water: Cyanobacteria, BMAA and ALS). However there might be no helpful microbes to protect us by removing similarly close analogs of our amino acids from an alien biochemistry

I looked at various other ways that alien life might accidentally cause harm for us or the biosphere, by various accidental metabolic products or toxins and so forth.

This is clearly just touching on a few ideas in a potentially vast topic of different ways that alien life based on a different biochemistry might interact with terrestrial biology. I found almost nothing on this, just the cites given here. I cover many other examples in the paper for both alien biology and related life.

This approach of developing specific scenarios for backward contamination is clearly just touching the surface of an unexplored topic. If any reader knows of anything else on this topic please let me know. This can surely be expanded on in future Mars sample return backward contamination studies.

MANY SCENARIOS WHERE MARTIAN LIFE IS HARMLESS - BUT AS FOR A SMOKE DETECTOR WE NEED TO FOCUS ON THE WORST CASES

There are also many scenarios where Martian life is as harmless as the non-native dandelions in the USA, or is beneficial to Earth’s biosphere. However the focus here is on protecting Earth. So, as for a smoke detector we need to focus on these worst-case scenarios to protect Earth.

Text on graphic: If Mars has native microbial life, it may well be harmless to Earth like dandelions in most of the USA:

… no real damage to the ecosystem. In fact, they are an excellent food source for many of the native bees, insects and other wildlife.”

But they could be pests for agriculture like the Giant African Snail - or harmful to humans or the environment - we need to know, not guess.

(Dandelion - Dent-de-lion ou pissenlit)

(Snail in Ubud, Bali, 2010)

FOR WORST CASE SCENARIOS WE DO NEED TO CONTAIN THE SAMPLES UNLESS WE STERILIZE EVERYTHING - THE ESF STUDY SET A FAR HIGHER STANDARD THAN A BSL-4 AND THE TECHNOLOGY DOESN’T EXIST YET AS WE’VE NEVER HAD TO CONTAIN ULTRAMICROBACTERIA

However, for the worst case scenarios, we do need to contain the samples - unless we simply sterilize all samples that return to Earth - so is NASA’s proposal adequate anyway because they use a BSL-4? Answer - No the ESF set a far higher standard in 2012

The Perseverance samples have so much contamination that sterilizing will make no difference. But let’s look at NASA’s proposal to use a BSL-4 (Biosafety level 4). Would this work to contain the samples? Is the mission safe anyway even though they got the rest wrong?

No, actually not. Their proposal relies on the science of 1999 (Mars Sample Return backward contamination–Strategic advice and requirements : 3).

I alerted NASA to this issue in the first sentence of my comment in the first round of public comments in May. The first two paragraphs read:

Are you aware of the ESF Mars Sample Return (Ammann et al., 2012:14ff)?

It said "The release of a single unsterilized particle larger than 0.05 μm is not acceptable under any circumstances”. This is to contain starvation limited ultramicrobacteria which pass through 0.1 micron filters (Miteva et al., 2005). Any Martian microbes may be starvation limited.

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).

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

They have a contact email address for all the comments but NASA didn’t use it. NASA didn’t respond to this comment in any way and didn’t mention it as a potential issue in the EIS.

As I explained there, the European Space Foundation in 2012 reduced the 1 in 1 million threshold used in a BSL-4 hugely, 20 fold from 0.2 to 0.01 microns and set a new threshold of 100% containment at 0.05 microns because of the discovery of ultramicrobacteria that can pass through 0.1 micron nanopores.

We don’t need to contain ultramicrobacteria in a Biosafety Level 4 facility because they are harmless for humans. But ultramicrobacterial from Mars might be another matter, as we saw, for instance mirror life. We can’t assume an ultramicrobacterium from Mars is safe for humans or our biosphere.

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)

The ESF set requirements are well beyond a BSL-4

RECOMMENDATION 7:
The probability that a single unsterilised particle of 0.01 μm diameter or greater is released into the Earth’s environment shall be less than [one in a million]

…

The release of a single unsterilized particle larger than 0.05 μm is not acceptable under any circumstances

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

Graphical summary:

Recent air filter technology reviews don’t mention any attempts to achieve 100% containment above any size. Also they don’t mention anything approaching 1 in a million chance of releasing a single particle in the lifetime of a facility at all sizes above 0.01 microns. See: (Application of Electrospun Nonwoven Fibers in Air Filters)

The ESF standard may be achievable in the future, perhaps with an air incinerator This is a suggestion by NASA astrobiologist Chris McKay (private communication). Everyone agrees extraterrestrial life from Mars would be sterilized by a few minutes of heating to 500°C. (A draft test protocol for detecting possible biohazards in Martian samples returned to Earth : Page 10)

The standards for a biosafety class III cabinet for a BSL-4 laboratory do include an option to use an air incinerator instead of the second HEPA filter. See page 37 of (Primary containment for biohazards: selection, installation and use of biological safety cabinets) Chris McKay’s idea is to use an air-flow incinerator instead of an oven.

This isn’t an oven however. The air flows through it and a microbe in a dust grain or a hardy spore from Mars might be able to survive better than terrestrial spores. There would be many extra steps to certify this for potentially hardier extraterrestrial life from Mars.

I discuss this in detail in the supporting materials. If NASA with to explore this, it still needs a new EIS.

• In any new EIS, NASA needs to compare it with the reasonable alternative of sterilizing the samples before they come to Earth. This maintains 100% safety for Earth's biosphere more simply, at lower cost and with no potential failure modes.
• We need to develop the specifications first - experts need to look into the size limit and the level of assurance needed, both of which need regular review according to the ESF in 2012. This review has not yet been done.

Once we know what needs to be achieved, NASA need to look into technology. However, this technology doesn’t exist yet. It would need to be developed, standards, tests, methods of replacing components etc.

The ESF study also said we need review of the level of assurance and maximum size of released particle.

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 : 21)

A decade later this review is needed first before we can design any air incinerators or filters to the new standard. The next 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). Panel 4 for the 1999 workshop estimated a minimum size of 12 nm in diameter and 120 nanometers in length for early life RNA world cells, if there is an efficient mechanism for packing its RNA (Size limits of very small microorganisms: proceedings of a workshop : 117).

As we learn more about the mystery of the first cell, these researches may lead to a review of the size limit to accommodate new ideas

We are a long way from solving the mystery of the first cell, but more and more of the puzzle- pieces are known. The problems, both dynamical and structural, have been identified, and for some, solutions proposed.

(Maintenance of Genetic Information in the First Ribocell).

Also the next size limit review might need to look at prions. Prions, are the result of protein folding, and trigger the formation of amyloid fibrils, the lowest energy states of a protein

“In addition, all proteins can adopt the true lowest energy state, the amyloid fibril.”

(Functional amyloids are the rule rather than the exception in cellular biology : figure 2)

These elongated fibrils encourage other similar proteins to fold in the same way and they coagulate together to form large lumps of protein

(How do yeast cells contend with prions? : Figure 1)

This a new issue raised by the Sterilization working group (Biological safety: 6) that’s not mentioned in the previous reports from 2009 (Assessment of planetary protection requirements for Mars sample return missions) and 2012 ( Mars Sample Return backward contamination–Strategic advice and requirements).

The sterilization working group report argues 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.

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). 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 aren’t infectious agents though, they arise frequently through spontaneous misfolding within the cells themselves.

However, 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).

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 Mars might be very small. It might be necessary to look closer at this, to look at whether prions from Mars could

• change the toxicity of terrestrial microbes, or
• harm terrestrial microbes

The review would need to look at what effects this could have on other organisms and the biosphere, if any. This may 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 for minimum size studies.

If we are going to return unsterilized samples to Earth, this review needs to be done first before developing the filter and / or air incinerator technology and relevant testing requirements, as requirements could change as a result.

But before then we need to do the updated Mars sample return review so that we know what we need to contain.

SIMPLE SOLUTION - STERILIZATION - BYPASSES ALL ISSUES

We can bypass all this with the simplest solution, to use sterilization.

We can keep Earth 100% safe by sterilizing all the sample that come to Earth. This will probably make no difference to the Perseverance samples since they have too much contamination for astrobiology.

The main question here is to select a level of ionizing radiation sufficient to sterilize the samples and optimized. Is it better to use gamma rays and a cobalt 60 emitter? Or is it better to use X-rays, perhaps tuned to particular frequencies? Or a combination of both?

However, the samples have likely had more than a sterilizing dose already even in recently exposed rocks. So the geology is already affected. This is most relevant if we can return recently exposed rocks or present day life.

Rummel et al. in 2002 put it like this (to paraphrase)

• The chemical elements and the bonds binding them together are the same on Mars and on Earth
• So a method of sterilization for terrestrial biology that works by breaking these bonds should work even if Martian life uses other elements, not even carbon. The energies holding the molecules together wouldn’t be much different.
• Gamma photons up to 30 megarads have virtually no effect on geology. They don’t induce radioactivity.
  “The only detectable effects are changes in albedo, color, and thermoluminescence in selected minerals. Isotopic and elemental compositions will not be affected regardless of gamma dose. … Sterilization at doses significantly above 30 Mrads may induce changes in crystallographic structure (caveat: research required)”
• Combining ionizing radiation with moderate heat or with oxidants in the samples increases the effect.
• They also suggest experimenting with supercritical fluids and commonly used organic solvents in case those might be useful in some situations,

They conclude:

On balance, if samples returned from Mars require biological sterilization, exposure to gamma rays may provide a feasible option

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

Although the current Perseverance samples are not likely to be affected by sterilization, because of the levels of terrestrial contamination - future samples or bonus samples in clean containers would be affected

IF HUMAN TECHNICIANS ARE INVOLVED WE NEED TO CONSIDER QUARANTINE - BUT QUARANTINE CAN’T KEEP OUT AN ALIEN FUNGUS OR MIRROR LIFE

The EIS doesn’t discuss the issue of human quarantine, which has been a major issue in previous Mars sample return reports. They avoid this by saying there is no risk to human health from the samples.

Once we say there is a potential for harm to humans we need to look at issues with lab leaks. Any biosafety lab has to do that, and there were several lab leaks that lead to quarantine of the technicians for the lunar samples.

I found issues with quarantine that haven’t been raised in any previous planetary protection report, even right back to the Apollo missions. If an epidemiologist had ever been involved in the debates, and been listened to the first thing they might say “but what about Mary Malone?”. She is a famous case in epidemiology, a life-long spreader of typhoid, but never showed any symptoms of typhoid herself (Mary Mallon: First Asymptomatic Carrier of Typhoid Fever).

Quarantine can’t protect against a life-long symptomless superspreader of a Martian fungal disease of humans or indeed, a disease of crops or mirror life. Yet there is no mention of Mary Mallone in any of the Mars sample return planetary protection reports.

Quarantine may be useful in the future if there is some specific lifeform from Mars that we need to keep out that can only survive on or in humans for a limited period of time. But right now with our current level of understanding, it is not possible to protect Earth in this way.

These issues with quarantine mean we can’t return unsterilized samples to a biosafety lab even if we can upgrade the technology to match the new size limit requirements whatever they are - because we have to be prepared for lab leaks.

We could still use the airflow incinerator idea, but it would need to be with a lab that can’t have leaks. That means one without human technicians as we don’t know how to make a failure free lab with human technicians.

NATURAL SOLUTION - TELEROBOTIC BIOSAFETY LABORATORY - BUT STILL MANY ISSUES

The natural solution is to return to a telerobotic biosafety laboratory facility. But this still leads to many issues to consider for a facility on Earth such as:

• Safe transport to the facility
• Maintenance
• Rigorous prevention of contamination either way
• No previous experience of operating such a facility
• Would even a telerobotic facility have no lab leaks?
• Sterilization of the entire facility when it’s decommissioned (e.g. if it contains mirror life)

ONE WAY TO SOLVE THIS IS A MINIATURIZED TELEROBOTIC FACILITY ABOVE GEO

That leads to the idea - why not a miniaturized telerobotic facility in a centrifuge above GEO? We wouldn’t have had the capability two decades ago. But we do have the technology today for a miniaturized telerobotic life detection lab above GEO for 100% planetary protection in the backwards direction. This is motivated by the incredible shrinking life detection instruments which now include:

• Life Marker Chip LDChip300 (antibodies) almost sent on Exomars but descoped which was able to discover a previously undetected microhabitat in the Atacama desert
  (A microbial oasis in the hypersaline Atacama subsurface discovered by a life detector chip: implications for the search for life on Mars)
  target mass of less than 1 kg (Life Marker Chip)
• Gene sequencer SETG (Search for Extraterrestrial Genomes project) designed to do end to end sequencing on Mars using the MinION nanopore sequencing technology. By 2016 it reached the capability to detect 10 ppb of DNA. It would be able to detect 400 highly conserved “universal genes” such as ribosomal DNA which would establish whether Martian life is related to terrestrial life, perhaps by meteorite transfer, or is independently evolved (SETG: nucleic acid extraction and sequencing for in situ life detection on Mars).
  
  It continues to be developed by NASA. SETG needs more work but is being actively explored by NASA for in situ detection for icy worlds (Nanopore sequencing at Mars, Europa, and microgravity conditions). It uses biodegradable organic nanopores at present with a short shelf-life, and NASA are exploring non biodegradable nanopores for longer missions to Mars and icy moons of Jupiter and Saturn, which would also help with issues of resupply of the nanopores to above GEO (Life detection and taxonomic characterization with MinION sequencing in Mars and icy worlds analogue environments : 230-1)
• astrobionibbler able to detect a single amino acid in a gram
  (Searching for Organics in a Nibble of Soil )
  (In Situ Microfluidic Subcritical Water Extraction of Amino Acids)
• a chiral version of the Viking labelled release experiment
  (A Chiral Labelled Release Instrument for In Situ Detection of Extant Life)
• An off-axis holographic microscope to let the focus be adjusted after the image is taken making it easier to image individual microbes in a liquid medium
  (A submersible, off-axis holographic microscope for detection of microbial motility and morphology in aqueous and icy environments)
• A method to check for redox reactions directly by measuring the electrons and protons they liberate. This is sensitive to small numbers of microbes and has the advantage that it could detect life even if not based on carbon or any form of conventional chemistry we know of
  . Microbial fuel cells applied to the metabolically based detection of extraterrestrial life.
• A miniature variable pressure electron microscope that combines imaging with in situ chemical analysis
  . Miniature variable pressure scanning electron microscope for in-situ imaging & chemical analysis.

Several instruments suggested for Europa:

• Tests for autofluoescence. Aromatic amino acids (incorporating a ring of six carbons) fluoresce when stimulated with deep UV at wavelengths less than 250 nm. Chlorophyll and some other biological organics also autofluoresce
• We could also use fluorescent dyes that bond to specific macromolecules such as lipids, proteins and nucleic acids
• We can also use this autofluorescence to directly search for the activity of swimming microbes
• Raman microspectroscopy synchronized with visible light can do a chemical analysis of the microbes directly
• Superresolution optical microscopy, which can go beyond the usual optical resolution limit of 200 nm to observe nanobacteria

(Report of the Europa Lander Science Definition Team)

This resolves all those issues. We can use a safe orbit in the Laplace plane above GEO, inclined at an angle to the plane of geostationary Earth orbit satellites - where Earth’s ring particles would orbit if we had a ring system. Even high area to mass particles can’t reach Geostationary Earth Orbit from this safe orbit.

We don’t have experience operating a telerobotic facility above GEO either of course. But we have a lot of experience of operating robotic missions on other planets. Operating telerobots above GEO would be similar to operating rovers on other planets but with high bandwidth and almost no latency.

We could also eliminate some of the small amount of residual latency with artificial real time, a technique used by online gamers and proposed by NASA as a way of speeding up robotic missions to Mars in the future once we have high bandwidth communications with Mars. I cover artificial real time in the supporting materials:

• Finding an inspiring vision for the future that works whether or not humans can explore and colonize the surface of Mars in spacesuits

I have suggestions for bonus samples of dirt, dust, atmosphere and a pebble collected from a recently exposed crater to a depth of 2 meters, to rescue this mission from the fiasco of likely returning no samples of any relevance to astrobiology. My suggestion does this in a way that will also protect Earth 100%.

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])

This idea of a telerobotic facility can be scaled up like the ISS but in miniature with modules from other countries - and perhaps eventually if needed - a teleoperated lab on the Moon

It can be scaled up to a larger international telerobotic laboratory like the ISS but in miniature (and a much smaller budget) with modules from other countries for analysis, sample preparation, sterilization, telerobotic handling.

If we find that Martian life is mirror life or in some other way so hazardous for Earth’s biosphere that it has to be contained far above a BSL-4, we may later need something larger and better resourced.

By then we likely have a permanent presence on the Moon. So, the best solution may be a telerobotically controlled laboratory on the Moon. This would be a step up from the orbital satellite while keeping it 100% contained more easily than on Earth.

Humans would still go nowhere near the facility but in a future where we have a permanent human presence on the Moon we could operate such a facility far more easily than one in GEO, for instance to install new robotic handlers, to add / remove materials, to service and maintain it etc especially if by then we need a large facility with large multi-tone instruments. We could even build a particle accelerator or accelerators on the lunar surface for such a facility to use.

CHANCE OF DETECTING PAST LIFE MAY BE VERY LOW - PREPARING FOR FUTURE SEARCHES

It’s also important to realize the situation is very different for life and for geology. In many scenarios the chance of detecting past life in samples returned from Mars may be 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).

Expanding on what I said in the introduction, astrobiologists have warned in many papers that even if past life was abundant in Jezero crater it needs special conditions to get deposited and preserved even in a delta, and not be destroyed quickly on formation. As Hays et al put it: “Many of the conditions that make an environment more habitable are destructive to one or more of the biosignatures of interest” (Biosignature preservation and detection in Mars analog environments : 4.4. Strategies and priorities).

The organics also need to survive unaltered for 3 billion years with many processes that can wash it out, such as later floods, alter it such as the perchlorates, hydrogen peroxide etc (A field guide to finding fossils on Mars) (Habitability, Taphonomy, and Curiosity's Hunt for Organic Carbon). Also there are many processes that can add to it and confuse our searches such as infall from space and non biological processes on Mars that produce organics (Biosignatures on Mars: what, where, and how? Implications for the search for Martian life : 999–1000).

Also we don’t know what capabilities it had. For instance one plausible scenario is that early life on Mars hadn’t yet achieved photosynthesis, or it never progressed to photosynthesis. If that is the situation, it could take a lot of searching to find past life. Several studies have raised this issue including this one from 2011.

If Mars evolved a biosphere, it may not have progressed to photoautotrophy or a dependence on photoautotrophy as it did on Earth. Thus, in the consideration of Martian environments conducive to producing molecular biosignatures, targeting depositional environments that had a strong chemical energy flux and sustained redox gradients for long periods by biogeochemical cycling is a most promising strategy.

(Preservation of martian organic and environmental records: final report of the Mars Biosignature Working Group)

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

We need to think of any samples returned from Mars as a first step. We may not yet know enough to intelligently select samples to return to search for past life, and may only return recognizable past life with a large measure of luck. However, what we learn may help us plan future in situ searches and sample returns.

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 (Lifeless Martian samples and their significance)

So this is the start, not the end of our searches for life on Mars, past and present. Even if we detect life there there would of course be many questions unanswered. So we need to look forward, beyond this mission to what we can do next.

A WAY TO SEARCH WITH 100% STERILE ROVERS TO EXPLORE EVEN THE MOST SENSITIVE PARTS OF MARS

I also have proposals for a way to unlock the whole of Mars for safe exploration without any risk of forwards contamination using 100% sterile rovers based on your remarkable Venus HOTTECH technology (HOTTech) . This uses a suggestion from the Venus lander team from 2018 (Automation Rover for Extreme Environments : Section 6.2) which is so much easier now with the technology NASA has developed since then in just the last 5 years. We now have the capability to build a fully functioning rover that can survive for months on the Venus surface at 500 C with all the components needed for a science mission (Long-lived in-Situ solar system explorer (LLISSE) Potential Contributions to solar system Exploration). The technology only reached this level of maturity in the last few years due to far-seeing investment by NASA in the future of Venus surface exploration.

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)

There may be other ways to do it, but this proposal shows we have at least one way to achieve 100% planetary protection in both directions and do it with no loss of science, indeed it should greatly boost our science capability.

WE DO HAVE THE CAPABILITY TO ELIMINATE PLANETARY PROTECTION RISKS BOTH WAYS 100% WITH CURRENT TECHNOLOGY

The sterilization working group said that it’s impossible to remove all risk without ceasing space exploration

“While it is impossible to remove all risk without ceasing space exploration, …

There is always some level of risk associated with exploration into the unknown, and it was the goal of the SWG to help manage the risks of possible adverse effects to the Earth’s biosphere while maintaining the science integrity of the returned samples.”

(Biological safety in the context of backward planetary protection and Mars Sample Return: conclusions from the Sterilization Working Group)

This is true for some risks. For as long as we do space exploration, at current level of technology there is no way to completely prevent

• robotic spacecraft crashing or malfunctioning,
• accidents involving astronauts
• malfunctions of space missions during launch or re-entry.

In worst cases these can affect humans on the ground not involved in the mission - though we can do much to minimize those risks too.

However, there ARE some risks we can eliminate completely. We do have the option to keep Earth’s biosphere 100% safe. This is a matter of our priorities as a civilization.

Based on a very high valuation of the importance of protecting Earth’s biosphere, we can always delay any activities until we find a way to do them that involves no risk to Earth’s biosphere, OR sterilize samples before we return them to Earth

My conclusion is that we now have the capability of 100% planetary protection both ways. It is our choice now as a civilization if this is what we want to do. It also leads to far greater science return - because once fully developed, which may not take more than a few years of work based on HOTTECH, we can look for life in situ anywhere on Mars without the need to target only locations for past life that were so restrictive for our missions so far - and without any risk of confusing forwards contamination.

RECOMMENDATIONS - TO RE-ESTABLISH INTER-AGENCY COMMITTEE, VERY MULTI-FACETED TO DO A PROPER MARS SAMPLE RETURN REVIEW

You also need to re-establish the inter-agency committee as recommended by the Space Studies Board so many times, with scientists from other agencies such as the CDC, Department of Agriculture etc. In 2018 the Space Study Board again recommended you re-establish such a committee.

(Assessment of planetary protection requirements for Mars sample return missions : Pages 67–8)

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 way this topic is under-resourced, and the lack of a mechanism for inter-agency dialog on this matter.

NASA did have an internal interagency panel for Apollo in the 1960s, but this was before NEPA. There were no public comments, and the ICBC was set up so that NASA could ignore the recommendations of other agencies and frequently did (When Biospheres Collide: A History of NASA's Planetary Protection Programs. : 129).

As we saw, NASA then had an interagency panel for a few years again starting in 2000 but they ordered the panel to stop meeting in 2005, closed it in 2006, removed all the scientists from other agencies from it, turned into the Planetary Protection subcommittee of NASA and that in turn was closed down in 2016. (Review and Assessment of Planetary Protection Policy Development Processes : page 26). We urgently need to reverse all those changes.

We also 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.

IN LONG TERM WE NEED MORE FUNDING FOR PLANETARY PROTECTION

I also found issues with the current levels of funding for planetary protection.

Funding may not be a major issue for this particular mission. The solution outlined here

• Costs less for NASA this decade
• Adds the cost of a satellite above GEO in the 2030s
• Leads to MUCH MORE science return.
• And keeps Earth 100% safe.

However in the wider picture, we might well encounter future scenarios where we can save costs by skimping on protecting Earth.

Given the high value humans assign to Earth’s biosphere, we need to look at costs not just to NASA but to the Earth for the worst-case scenario where Earth’s biosphere or human health is harmed. The world is better saved by a space agency that has extra funding to ensure it does planetary protection properly. It seems perverse for NASA to have strong financial incentives to skimp on planetary protection.

The Viking mission cost an extra 10% in order to protect Mars from terrestrial contamination (Cost of Planetary Protection Implementation : page 3) (Review and Assessment of Planetary Protection Policy Development Processes : page 35) which seems an appropriate figure, for missions that need it.

Typical planetary protection costs range from 0.4% to 1.1% (Cost of Planetary Protection Implementation : page 3). We surely need a % at least as large available for forward protection and to protect against backwards contamination IF IT IS NEEDED. Some of this could then be spent on

• telerobotics above GEO and pre-sterilization of samples returned to Earth,
• adapting the Venus HOTTECH to achieve 100% forward planetary protection
• high bandwidth optical communications with Mars to enable a rapid astrobiological survey of the planet

With the planetary protection office gone and the interagency panel gone, about the only source of independent review we now have is the Space Studies Board but they also are under resourced.

They themselves say they have a limited pool of planetary protection experts to draw on and are unable to provide advice on short time scales - and we need new mechanisms to respond more rapidly.

Finding: The SSB’s international leadership role in planetary protection has been a reflection of the dominant U.S. role in the robotic exploration of the solar system and NASA’s sustained interest in securing and using scientific advice from the SSB, but those factors are not necessarily guaranteed in the future. The SSB has been reactive to requests from NASA rather than proactive, constrained by the limited pool of planetary protection experts to serve on study committees, unable to provide advice on short time-scales, and focused on issues for robotic scientific missions.

Recommendation 4.3: The SSB and NASA should pursue new mechanisms to anticipate emerging issues in planetary protection, respond more rapidly, and address new dimensions such as private-sector missions and human exploration. Future decadal survey committee’s should give greater prominence to planetary protection issues and play a more proactive role in their identification and possible resolution.

(Review and Assessment of Planetary Protection Policy Development Processes : page 78)

WHY IT IS SO IMPORTANT TO CHANGE COURSE NOW BEFORE COMPLETION OF THE EIS

I very much hope that NASA can change course now, before completion of the EIS.

You have a legal requirement to respond to substantive public comments such as mine in the final EIS . § 1503.4:

An agency preparing a final environmental impact statement shall consider substantive comments timely submitted during the public comment period.

If you can change course now, NASA will have far more flexibility to find a way forward. As I mentioned in the open letter, if it goes as far as an EIS I think your approach is legally vulnerable to at least four of the main NEPA requirements on an EIS:

• requirement to maintain scientific integrity § 1502.23 [Links directly to the legal text]. For instance, with cites that directly contradict the sentences they are cited to.
• provide rigorous analysis of reasonable alternatives . § 1502.14 - no discussion of the alternative to delay the mission until you have a better way to protect Earth (Comment posted December 20th), and a one sentence dismissal of the alternative to sterilize the samples first (MSR draft EIS : 4–2) as suggested by myself (Comment posted on May 16th) and seven others in the first round of public comments
• consider all major points of view on the environmental impacts . § 1502.9 - the EIS presents the view that there is no significant risk of environmental effects (MSR draft EIS : 3–16), and doesn’t alert the reader even to the existence of opposing views in sources such as the NRC Mars sample return study in 2009 (Assessment of planetary protection requirements for Mars sample return missions : 48), the ESF Mars sample return study in 2012 (Mars Sample Return backward contamination–Strategic advice and requirements : 28) and indeed the entire body of the previous planetary protection literature to date including the views of Carl Sagan (The Cosmic Connection – an Extraterrestrial Perspective) and Joshua Lederberg (Parasites face a perpetual dilemma), American pioneers in planetary protection from the late 1950s onwards.
• use an interdisciplinary approach integrating the natural and the social sciences. § 1507.2 - previous studies such as the ESF study emphasize the need to set up fora dedicated to ethical and social considerations of the risk at an international level open to representatives of all countries and to have transparent methods to communicate accountability, benefits, risks and uncertainties (Mars Sample Return backward contamination–Strategic advice and requirements : 59). This was not done.
  
  Also many of the errors I found show you haven’t followed an interdisciplinary approach. Your decision to close down the interagency panel Review and Assessment of Planetary Protection Policy Development Processes : page 26) and your planetary protection office (With planetary protection office up for grabs, …), against the recommendation of the Space Studies Board (Review and Assessment of Planetary Protection … : 61 - 62) surely contributed to this lack of a sufficiently broad interdisciplinary approach.

You’d need to consult an expert on NEPA but it seems likely they would advise you that this EIS would not stand up to any legal challenges.

If you stop the EIS now you can fix the issues in your own time, and not be bound by whatever decision a justice might make if it comes to a court case. If it survived NEPA it’s even more damaging for NASA if it is stopped under the presidential directive NSC-25, which requires the president to order

• a review of large scale effects that could be reasonably expected to result in allegations of major or protracted effects.

It has to be done even if the agency feels confident such allegations are false (Presidential Directive NSC-25: Scientific or Technological Experiments with Possible Large-Scale Adverse Environmental Effects and Launch of Nuclear Systems into Space)

Then it seems to me, the worst case for NASA is if nothing is done until the 2030s when with mounting public concern, as experts from many disciplines examine the EIS again they only find out how flawed your plans are then, and you are stopped by a bill in Congress. The space lobby is strong but so also are the farmers, fishermen, public health etc and they have far more legislators behind them.

AND NEED TO GUARD AGAINST SUCH MISHAPS IN THE FUTURE

Meanwhile, as a matter of scientific integrity, it seems important to find a way to guard against similar mishaps in future environmental impact statements for Mars sample return missions and indeed for similar missions from Ceres, Europa, Enceladus or anywhere else that might have life.

An EIS should consider carefully any proposals that would be safer for Earth’s biosphere, even if they might cost significantly more. If they are rejected for reasons for costs, this needs to be explained to the public who might then find the funding based on the priority many have for protecting Earth’s biosphere.

This survey and these recommendations are covered in more detail in my preprint, which also has new example scenarios to help motivate space agencies to protect Earth, such as mirror life, see link below.

• .NASA must protect Earth's biosphere even if Mars samples hold mirror life – a survey of recent planetary protection research plus new scenarios – and how with modern technology we now have an option to keep Earth 100% safe – and protect any Martian biosphere 100% too

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