Dear NASA planetary protection office and other interested parties.
[Please forward to your point of contact for comments on the draft EIS]
This is about your Environmental Impact Statement (EIS) for samples you plan to return from Mars in the early 2030s. The Council on Environmental Quality advises the public that if our concerns aren’t resolved during comments on the EIS, we need to contact the agency:
Your first line of recourse should be with the individual that the agency has identified as being in charge of this particular process. (page 28 of A citizen’s guide to the NEPA: Having your voice heard.)
I tried an email to your office on December 18, 2022, and got no reply. This is an open letter, which I will post to the internet and archive, and I will email a link to you together with a video presentation. I am expecting a reply as per the CEQ advice.
NASA has been world-leading in its protection of Mars from forward contamination – from any terrestrial life that might get there and proliferate in any habitats that might exist in the Martian desert landscape.
You have also been world-leading in your literature on a Mars sample return.
But sadly your current EIS is not world-leading.
I end this post with a suggestion on how you can move forward from this EIS with a new approach that would
My literature 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.
This is a short summary of some of the main points in my preprint. I will also use this page and the graphics as the basis for the video presentation. For citations in this open letter I just give the title in brackets hyperlinked to the paper.
The title of each section also summarizes its main conclusions similarly to an abstract. You can get a good first idea of this open letter by just reading the titles of sections - and looking at any graphics.
John Rummel, NASA planetary protection officer from 1986–1993, puts it like this as interviewed by Scientific American in 2022 after the first round of public comments on your proposals:
“In the first place, we don’t know everything we want to know about Mars. That’s why we want the samples.
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
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.”
(Dr. Catharine Conley) for her dates as NASA planetary protection officer
Of course, we won’t find Ebola on Mars, it’s just an example to show how deadly the worst case could be. But in the worst case, we may find diseases of humans that are just as deadly. There are many illustrative examples in the planetary protection literature.
There are several diseases not adapted to humans or any higher life mentioned in the planetary protection literature. Tetanus still kills thousands of newborns every year who miss out on vaccination and is not adapted to humans and Legionnaires disease is an example of a disease of biofilms which infects human lungs opportunistically because it resembles a biofilm and is sometimes deadly (Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions)
As a result of my literature survey I’ve added another illustrative example of Aspergillus fumigatus, a fungus not adapted to humans with 200,000 cases of invasive aspergillosis a year and a 30% to 95% fatality rate (Hidden killers: human fungal infections) 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).
I cover this also in my open letter to the CDC which I plan to send to them to help raise awareness in other US agencies. They are one of numerous agencies that need to look at the plans given that there is a possibility of impact on human health in worst case scenarios.
. Open letter to CDC (draft) - MIDEDIT (PLEASE DON’T SHARE WIDELY, READY SOON)
We now have many terrestrial organisms that do well in Mars simulation chambers including lichens, mosses, fungi, various bacteria, and algae. See: (Habitability of Mars: How Welcoming Are the Surface and Subsurface to Life on the Red Planet?)
This includes Chroococcidiopsis, a highly resilient blue-green algae which does well in Mars simulation conditions (Protection and Damage Repair Mechanisms Contributed To the Survival of Chroococcidiopsis sp. Exposed To a Mars-Like Near Space Environment).
This algae can be found almost everywhere on Earth from tropical reservoirs and oceans to cold dry deserts and even in complete darkness in gabbro 10 -750 meters below the Atlantic sea bed using an alternative metabolic pathway with hydrogen as a source of energy (Recycling and metabolic flexibility dictate life in the lower oceanic crust). Gabbro and basalt are amongst the most common rocks on both Mars and Earth.
Chroococcidiopsis is a pioneer “prime producer” that doesn’t depend on any other life and can find all its 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. Strains of chroococcidiopsis do well in both hot deserts and very cold Mars analogue deserts in Antarctica (Ancient origins determine global biogeography of hot and cold desert cyanobacteria ), and also in warm wet conditions up to human body temperature, for instance in the upper throat behind the nose (Nasopharyngeal Microbiota as an early severity biomarker in COVID-19 hospitalised patients)
If Mars has an analogue of Chroococcidiopsis, a photosynthetic lifeform that lives in basalt and uses sunlight as an energy source it may already be adapted to survive on Earth and to proliferate and spread widely as it evolves to terrestrial habitats.
As John Rummel said, we need respect for the unknown. NEPA requires agencies to ensure scientific integrity of the discussions and analyses in the EIS.
Agencies shall ensure the professional integrity, including scientific integrity, of the discussions and analyses in environmental impact statements
§ 1502.23 [Links directly to the legal text]
However, they have no mechanism to ensure scientific integrity except public comments. I commented on your first round of public comments on May 16. The draft EIS didn’t mention many serious issues I raised with your plans. I commented on the second round on November 28th, December 5th, December 13th and December 20th. These raise very serious issues with the scientific integrity of the EIS.
I emailed your point of contact Dr Alvin L,. Smith II on 18th December. I got no response.
Since my unanswered email to you on 18th December, I’ve been working on a preliminary survey of the recent literature. This builds on research for a paper about planetary protection for NASA’s Mars sample return mission which was almost ready to send to academic journals at the time of my public comments last year.
The last thorough review is the NRC study, published in March 2009, just before the Phoenix team first published their observations of possible droplets of salty water on the Phoenix lander’s legs, later confirmed in simulation experiments as likely the first direct confirmation of (very cold) surface salty water on Mars. These are the droplets they simulated, coloured in green.
Possible droplets on the legs of the Phoenix lander – they appeared to merge and sometimes fall off. In this sequence of frames, the rightmost of the two droplets grows and seems to do so by taking up the water from its companion to the left, which shrinks - highlighted in green in this black-and-white photo from Mars (Liquid Water from Ice and Salt on Mars).
When Nilton Renno’s team successfully simulated these droplets in a Mars simulation chamber in 2014 he put it like this:
This is a small amount of liquid water. But for a bacteria, that would be a huge swimming pool – a little droplet of water is a huge amount of water for a bacteria. So, a small amount of water is enough for you to be able to create conditions for Mars to be habitable today. And we believe this is possible in the shallow subsurface, and even the surface of the Mars polar region for a few hours per day during the spring.
, How liquid water forms on Mars, (transcript from 1:48 onwards)
This discovery lead to many more indirectly detected or proposed salty brines on Mars, some of which may be habitable to Martian life.
The science has moved forward so much in the 14 years since 2009, including many proposed martian microhabitats, the surprising resilience of terrestrial microbes in Mars simulation chambers, new experiments in the transport of microbes and fragments of microbial biofilms in Martian winds, and new discoveries about terrestrial microbes living in Mars analogue cold dry deserts.
My preliminary literature survey identified many areas for review in an update of the 2009 study. I also added new illustrative backward contamination scenarios such as mirror life, to help focus attention of space agencies on the need to protect Earth.
See:
Almost none of this literature is mentioned in the EIS. One of the conclusions of my preprint is that NASA needs to commission another planetary protection back contamination review before it is feasible to do a thorough EIS for an unsterilized Mars sample return. If space agencies are serious about protecting Earth, they need to take account of the many new developments as a result of 14 years of research since 2009.
It would be possible to return samples sterilized before they reach Earth without such a review.
This open letter is another attempt to contact you with the main outlines of my preliminary literature survey in place.
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)
[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.”
From: [The Cosmic Connection – an Extraterrestrial Perspective]
[Text transcribed from graphics in this open latter for visually impaired readers]
It’s strange to write this to you, as a long-term admirer of NASA, 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.
This is one of three arguments in the EIS of central importance as precedent because others could use it to reason in good faith, but mistakenly, that we already know there is no life on Mars and so, that it is safe to drop all precautions to protect Earth’s biosphere from Mars samples.
You say
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)
Your most recent citation for “existing credible evidence” is about a search for current habitats on Mars!
“The exploration of … Mars … will help establish whether localised habitable regions currently exist within these seemingly uninhabitable world”.
(Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology : page 393 [Click on the X to close the splash to go straight to page 393])
This is a screenshot of that page (for video presentation).
NASA’s most recent citation for “Existing credible evidence suggests that conditions on Mars have not been amenable to supporting life as we know it for millions of years” is about a search for CURRENTLY HABITABLE ENVIRONMENTS on a seemingly uninhabitable world.
But one of your own science goals has the search for present-day life and habitats as the second part of Goal 1 in your 2020 update of the Mars exploration program science goals!
Goal 1: Determine if Mars ever supported or still supports, life,
(MEPAG Science Goals, Objectives, Investigations, and Priorities : page 9)
It is also objective 2.3 for the Mars samples, to test to see if there is any evidence for present-day life - in the very samples Perseverance is caching and that you plan to return with this mission in the 2030s.
2.3 Modern biosignatures: Assess the possibility that any lifeforms detected are still alive or were recently alive.
This table is based on the conclusions of the iMOST team (International MSR Objectives and Samples Team). [MSR = Mars Sample Return]
The objectives described by iMOST are now NASA official policy for the returned samles - the iMOST conclusions were adopted in the final report the Mars Sample Return Science Planning Group in 2022.
The scientific objectives of MSR are comprehensively described by iMOST
(Final Report of the Mars Sample Return Science Planning Group 2 (MSPG2) : page S-21)
The iMOST team say the probability of discovering present-day life at the Martian surface is considered to be low, but it would be such a profound discovery we need to look for it.
The probability of discovering extant life at the Martian surface (including by means of MSR) is generally considered to be low. However, its discovery would be so profound that it would shake the pillars of science. It would yield insight into the very fundamentals of life such as what are the basic universal properties of living systems … and how life evolves
The iMOST team find present-day life on Mars plausible, because of (pages 86–7)
They conclude that native life on Mars may be able to adapt and evolve to the local conditions. See page 87 (iMOST).
To search for present day life they will
[See page 91 of (iMOST)]
NASA would then use a similar strategy to the Viking labeled release. Add some of the samples to a growth medium and see if there is any sign of microbes that use the organics and produce evolved gases like CO2 or methane. They would do that by replacing some of the carbon with Carbon 13, nitrogen with Nitrogen 15 and hydrogen with deuterium so they can keep track of what happens with the atoms in the growth medium.
This would be a major advance over Viking which couldn’t even detect if the evolved gas was methane or carbon dioxide, or something else.
[See page 92 of (iMOST)]
Then finally they would attempt to get any Martian life to replicate. If they do succeed in this, they would study the cells and look also for any structures they might be using to move around (this would include the flagella, long filaments that which terrestrial microbes often use to swim).
They conclude:
Success in cultivating organisms from Martian samples would be the ultimate proof of extant life. On Earth we can only culture a few percent of all environmental microorganisms because it is difficult to predict and reproduce conditions amenable to growth. We expect that Martian organisms would be no less recalcitrant. Therefore, it is critical that growth experiments be conducted under conditions present at the sample site.
[See page 93 of (iMOST)]
So, though the iMOST team think the chance of present day life is likely low, they recommended that NASA do extensive tests to try to find present-day Martian life in the samples.
NASA’s draft EIS does refer to the iMOST team objectives (Mars Sample Return DRAFT EIS : 1–11) saying:
The science potential of samples delivered from Mars was most recently re-evaluated by the international MSR Samples and Objectives Team (iMOST), which was active from 2017 to 2018
However, it doesn’t mention the interest in searching for present day life.
So - going back to NASA’s sentence in the EIS:
Existing credible evidence suggests that conditions on Mars have not been amenable to supporting life as we know it for millions of years
Why doesn’t your draft EIS mention that NASA plans to test the returned samples to see if there is any present-day Martian life in them?
It could be a simple lack of communication between the engineering team and the life detection scientists. Such things happen, like the mix-up that led to the loss of the Mars Climate Orbiter which crashed into Mars in 1999 (In Depth | Mars Climate Orbiter – NASA Solar System Exploration).
Or maybe it is optimism about their respective goals.
For scientists devising experiments to look for life, the most interesting outcome by far is present-day life. The iMOST authors recommend NASA to test for present-day life even if it may be unlikely, because it would be such a major discovery.
For engineers and mission planners preparing protocols to protect Earth, the less the risk, the lower the cost of the mission. So, it is natural for optimistic planners to find it more plausible that Mars has been uninhabitable for millions of years, as this will likely reduce the cost of the mission and make mission planning simpler.
Whatever the reason, if we take the protection of Earth seriously it is important to look carefully at worst-case as well as best-case scenarios. If we do that, just look clearly at the data as it is, we can get surprises. We may find a “win win win” solution that optimizes all our goals at once.
I end this open letter with exactly such a proposal (with bonus samples) that
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. Perhaps this needs extra legislation to mandate NASA to spend extra if necessary to protect Earth? It’s understandable that NASA mission planners are motivated above all by the need to reduce cost for their missions. But I’d argue that in this case - AND in the forwards direction - 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.
My conclusions were that it seems that this mission can likely be made 100% safe at no extra cost with more science return. However, in the larger picture we may need more funding for 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.
No mission since then has allocated anything like 10% of its funding to protect against forward contamination. 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 to protect against backwards contamination IF IT IS NEEDED. It could be an extra ring-fenced budget at 10% per mission that can be drawn on as needed for planetary protection.
That is a matter for public debate.
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 an EIS will need to look at reasonable alternatives that keep Earth 100% safe. If any proposals that would be safer for Earth’s biosphere are rejected for reasons of cost, this needs to be explained to the public.
This is one of three arguments in the EIS of central importance as precedent. Though you don’t use it this, way, another country or private space might use the statement in your EIS to argue in good faith, but mistakenly, that Mars is as uninhabitable as the Moon. They might then see no need to take any precautions to protect Earth.
This is of especial importance because of the high regard NASA enjoys internationally for scientific integrity and rigour – normally a well-deserved reputation.
So you need to get this right. WE DO NOT KNOW THAT MARS IS UNINHABITABLE at this moment in time, and your own citation and your own mission objectives for the samples returned from Mars contradicts your conclusion.
This is the second of your main arguments that others could use to drop protection of Earth’s biosphere. Other space agencies and private space could use your reasoning to argue in good faith, but mistakenly, that we know any life in their samples got here already. So NASA needs to be very sure to get this right.
You say in the EIS that any life in Jezero crater will get here better protected and faster in a meteorite than in a sample tube.
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
It is not credible that most microbes could get here better protected and faster in a meteorite. To get here in a meteorite a microbe has to get into it first. Large meteorites hit Mars every few hundred thousand years and the ejected rocks we have from Mars come from at least 3 meters below the surface.
Mileikowsky et al., author of a seminal paper on modern lithopanspermia (transfer of microbes between planets inside rocks), put it like this
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
Concomitantly with their resistance to the adverse effects of drying, microorganisms in anhydrobiosis or spore stage are resistant to the effects of freezing to very low temperatures, elevated temperatures for brief periods, and the effects of ionizing. 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 : page 401)
As for getting here faster, the most recent opportunity for any life to get from Mars to Earth was after the impact that formed the Zunil crater on Mars around a million years ago (direct crater count suggests 700,000 years ago) (Hartmann et al, 2010).
Any samples returned by Perseverance will get here in far less time than the approximately 700,000 years since the last meteorite was ejected from Mars to Earth.
Your own citation for "potential Mars microbes would be expected to survive ejection forces and pressure" makes this very point. It is a study of planetary protection requirements for Mars’s moon Phobos. Any life in samples from Phobos has already survived ejection from Mars. But samples from Mars are in a very different situation.
It says that potential Mars microbes in some surface materials (like dust and dirt and salt) would NOT even get into a meteorite.
"MSR [Mars Sample Return] 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"
(Planetary protection classification of sample return missions from the Martian moons : page 5 [use X to close splash])
There is a minor typo on this page, “Mars” for “Phobos” which could conceivably partly explain the confusion, and why this was selected as a citation for the EIS statement?
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"
The Phobos sample return study covers this reasoning in more detail on page 44-5. On the last point they say:
The reasoning regarding natural flux does not apply directly to samples returned from the Mars surface.
- The material will be gently sampled and returned directly to Earth.
- 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.
Samples with current liquid water and recent ice seem especially fragile to natural transport to Earth.
Finding: The committee finds that the content of this report and, specifically, the recommendations in it do not apply to future sample return missions from Mars itself.
[Added bullet points to the original text]
(Planetary protection classification of sample return missions from the Martian moons : page 43 [use X to close splash])
In short, your citation is a planetary protection study for samples returned from Mars’s moon Phobos and says clearly that it shouldn’t be used to support a meteorite argument for samples from Mars itself. It says it shouldn’t be used to support the very argument you use it as a citation for.
This is a particularly clear case. To use it in this way without alerting the reader to the discrepancy fails NEPA requirements for scientific integrity.
The EIS doesn’t alert the reader to this discrepancy.
Since most terrestrial microbes can’t get from Mars to Earth, it’s not very plausible that in ALL possible scenarios for Martian life, ALL species of martian microbes would be able to get from Mars to Earth - yet that’s what would be needed to prove we can’t have invasive species from Mars in the samples.
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. However, European starlings can’t fly across the Atlantic, which is how they could become an invasive species in the USA. The Department of Agriculture estimates that 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
This doesn’t mean that all European birds would be invasive in a harmful way. 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.
Didymo in the illustration in the last section is an invasive species of 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 which shows that microbial life can be invasive too (Diatoms as non-native species)
Just as it’s microbes that can’t cross oceans that have some potential to be invasive on Earth, it’s any microbes that can’t cross the cold and vacuum of space and can’t survive ejection from Mars or get into a meteorite that are the ones that have some potential to be invasive introductions to Earth’s biosphere.
This again is of central importance.. Another country or private space might use NASA’s statement to argue in good faith, but mistakenly, that any life from Mars has already got to Earth.
The natural delivery of Mars materials can provide better protection and faster transit than the current MSR mission concept.
. MSR DRAFT EIS 3–3
They might then see no need to take any precautions to protect Earth.
WE DO NOT KNOW THAT ANY SPECIES ON MARS HAVE EVER BEEN TRANSFERRED TO EARTH IN A METEORITE and as we saw, your own citation says it shouldn’t be used for this argument (Planetary protection classification of sample return missions from the Martian moons : page 5 and page 43 [use X to close splash])
Your EIS considers a best-case where
I will show in this open letter that NONE of these statements are supported by your citations. The EIS doesn’t alert the reader to many ways these assumptions could be invalid.
If this is not challenged, other space countries and private space may well use your arguments to infer in good faith there is no need to take ANY precautions for samples returned from Mars.
There are lots of ways that the sample returned from Jezero crater COULD be harmless.
However, despite the statements in your EIS, we DO NOT KNOW ANY OF THESE THINGS.
Margaret Race, a biologist working on planetary protection and Mars sample return for the SETI Institute and specialist in environmental impact analysis used the analogy of a smoke detector in response to similar non-peer-reviewed suggestions by the space colonization enthusiast and leader of the Mars Society Robert Zubrin:
If he were an architect, would he suggest designing buildings without smoke detectors or fire extinguishers?
Hazardous Until Proven Otherwise, in: "Opinion: No Threat? No Way",
Hand installing smoke detector labelled “NASA” and wooden ceiling of a house labelled “Earth”
Margaret Race made a relevant point in another paper. To summarize her main points she says scientists are likely to focus on
So it is natural for you to focus on those.
The general public are likely to focus on
(Planetary Protection, Legal Ambiguity, and the Decision-Making Process for Mars Sample Return : page 348)
We see the results of this different focus in the report.
Let’s look at another example:
NASA: (paraphrase) If there is life on Mars it can’t get into Perseverance's samples in Jezero crater:
“Consensus opinion within the astrobiology scientific community supports a conclusion that the Martian surface is too inhospitable for life to survive there today, particularly at the location and shallow depth (6.4 centimeters [2.5 inches]) being sampled by the Perseverance rover in Jezero Crater, which was chosen as the sampling area because it could have had the right conditions to support life in the ancient past, billions of years ago. (Rummel et al. 2014, …)”
.. MSR DRAFT EIS 1–6
Your EIS doesn’t cite the MEPAG2 review in 2015 which found knowledge gaps in SR-SAG2 about transport of life in the atmosphere and a potential for habitats even in places like Jezero Crater that may be impossible to see from orbit.
Rummel et al. is the 2014 SR-SAG2 review (A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2)) [Their second source for this sentence, Grant et al, is just a cite for the selection criteria for Jezero crater]
SR-SAG2 uses maps to map out uncertain regions that may contain “Special regions” which are defined as regions (SSB, 2015 :6).
“within which terrestrial organisms are likely to propagate, or a region which is interpreted to have a high potential for the existence of extant martian life forms.”
It doesn’t discuss the potential for Martian life so that already is a limitation for backwards contamination since Martian life might conceivably be capable, for instance, be able to live in cold salty water beyond the limits for terrestrial life. It just says:
At present there are no Special Regions defined by the existence of extant martian life, and this study concentrates only on the first aspect of the definition.
(SR-SAG2 : 888)
NASA and ESA commissioned a review in 2015 by the Space Studies Board, ESSC and NASEM, which found serious knowledge gaps in the 2014 SR-SAG2 review which you rely on here and especially the way it relies on maps from orbit.
Text on graphic: SR-SAG2 recognizes the need for buffer zones around the RSLs …
but MEPAG Review says it
- doesn’t adequately discuss transport of life in Martian atmosphere [ e.g. dust]
- only briefly considers implications of our lack of knowledge of new microhabitats impossible to see from orbit [microscale conditions]
[paraphrases (Review of the MEPAG report on Mars special regions :11 - 12) ]Map from: (A new analysis of Mars “special regions”: findings of the second MEPAG Special Regions Science Analysis Group (SR-SAG2) : Fig. 47 )
Perseverance landing site marked
NASA and ESA were planning independent reviews and finding both had the same concerns combined it in a single review. They commissioned this review partly out of concerns that MEPAG is not independent from NASA.
There were two reasons why both agencies [NASA and ESA] took the seemingly unusual step of independently commissioning reviews of a review paper that was to be published in a peer-reviewed journal.
First, there is the perception in some circles that MEPAG is not independent and that its views are too closely aligned with NASA’s Mars Program Office.
(Review of the MEPAG report on Mars special regions: xi – xii).
[by the Space Studies Board, the European Space Sciences Committee and the National Academies of Sciences, Engineering, and Medicine]
This review found that SR-SAG2 doesn’t adequately discuss the transport of material in the Mars atmosphere [e.g. in dust storms] see page 12.
This is indeed a knowledge gap. Amongst several relevant discoveries, later research found that small fragments of biofilm, thin layers of a microbial colony three hundredths of a millimeter thick, can travel 100 kilometers in daylight in the light Martian winds before it is sterilized.
Billi et al’s paper on biofilm transport doesn’t take account of the effect of UV on perchlorates in the biofilm, but in my paper I find
Also Wadsworth et al who highlighted the biocidal effect of perchlorates activated to cholorates and chlorites by UV only tested b. subtilis and remark that terrestrial extremophiles could be more resilient. Mars could have native evolved Martian microbes more resilient than the b. subtilis tested by Wadsworth et al..
The 2015 Space Studies Board review also found that SR -SAG2 only briefly discussed the implications of our lack of knowledge of microenvironments.
(Review of the MEPAG report on Mars special regions : 12 )
SR-SAG2 gave a useful list of these microenvironments by type:·
However, it doesn’t discuss them much further. These potential microenvironments on Mars have been the subject of many research papers which the EIS doesn’t discuss.
To take an example, that may be relevant to Jezero crater, terrestrial microbes can exploit water that condenses in micropores in salt or gypsum in deserts when the rest of the desert air is far too dry for life. Your former planetary protection officer Cassie Conley suggested that the same thing might happen on Mars. (Going to Mars Could Mess Up the Hunt for Alien Life) as did Paul Davies (The key to life on Mars may well be found in Chile) and Wierzchos et al. (Microbial colonization of Ca‐sulfate crusts in the hyperarid core of the Aacama Desert: implications for the search for life on Mars).
The SSB review also drew particular attention on page 11 to the capability of microbes to use biofilms to make regions habitable that wouldn’t be otherwise.
The Atacama gritcrust would be an example here (The grit crust: A poly-extremotolerant microbial community from the Atacama Desert as a model for astrobiology)
For scientific integrity your Environmental Impact Statement needs to cite the 2015 review and discuss what it says. This is especially important since the 2014 SR-SAG2 was seen as too closely aligned with the aims of NASA’s Mars Program Office, as one of the two main reasons for the 2015 review.
Also it needs to recognize that these weren’t backwards contamination studies and didn’t consider the question of what might count as a habitat for an alien biology. In all these examples we need to bear in mind that if there is Martian life, it has adapted to those conditions for billions of years and may be based on a different biochemistry with capabilities terrestrial biochemistry doesn’t have.
Your sterilization working group comes to a conclusion that is not found in any previous peer-reviewed study on Mars sample return backward contamination.
“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 in the context of backward planetary protection and Mars Sample Return: conclusions from the Sterilization Working Group: page 6)
They reach this conclusion by only examining diseases adapted to humans.
They don’t cite this to any previous study, and I have not been able to find any precedent except a non peer reviewed op ed. by Robert Zubrin (Contamination From Mars: No Threat) which was strongly criticised by experts including your planetary protection officer at the time John Rummel:
John Rummel: How ought others judge the cost-benefit ratio of Mars exploration if we don't take simple precautions to avoid potentially harmful consequences? Harshly, I suspect.
Margaret Race: If he were an architect, would he suggest designing buildings without smoke detectors or fire extinguishers?
Zubrin makes all three of the main arguments used in the EIS - NONE OF THESE OCCUR IN THE PEER REVIEWED PLANETARY PROTECTION LITERATURE
It is a striking similarity. There is no reason to suppose the sterilization working group was influenced by Zubrin’s non peer reviewed op ed. and they don’t cite it. But there may be a common background, which I discuss in my preprint, such as enthusiasm for physical exploration and pushing through frontiers, a focus on the mission objectives, a keenness to send astronauts to Mars, and a pre-existing optimism, possibly inspired by science fiction, that if there is anything on Mars it can’t harm us.
However in the worst case scenario we find interesting life on Mars that is harmful to Earth and can never be returned to Earth. This is currently a possible scenario. It could envigorate space exploration and lead to more rather than less public interest and enthusiasm for astronauts in space.
The sterilization working group doesn’t discuss the illustrative examples from the 2009 paper: Assessing the Biohazard Potential of Putative Martian Organisms for Exploration Class Human Space Missions
Indeed the passage discussing the potential for martian microbes to infect humans on page 6 has no citations for any of the diseases or to the planetary protection literature.
In this way they missed:
The sterilization working group doesn’t alert the reader to the existence of such diseases.
The sterilization working group does discuss Candidas, a fungal infection that they correctly say has adapted to humans over long periods of time.
As with the other diseases, the passage gives no citations for their statement about Candidas. I was able to confirm that experts say it is adapted to humans. But the natural next question for someone looking for worst-case scenarios rather than best-case scenarios is - what about other fungal infections of humans? Are they adapted to us?
I can’t find previous discussions of fungal infections in the Mars sample return literature, so needed to do my own research into this. To date, the planetary protection literature hasn’t tried to be comprehensive and only looks at a few illustrative examples.
Following up this example I found an example new to the planetary protection literature (as far as I know).
The two most deadly fungal infections for humans are Candidas and Aspergillus. Aspergillus fumigatus is NOT adapted to humans. We get an estimated 200,000 life threatening invasive aspergillosis infections a year with mortality rates varying from 30 to 95%. This disease affects people who are immunocompromised mainly.
. Hidden killers: human fungal infections.
The progressive and very serious disease of chronic pulmonary aspergillosis (CPA) affects around 400,000 globally and only occurs in people who are not immunocompromised with symptoms of “weight loss, profound fatigue, productive cough, significant shortness of breath, and life-threatening hemoptysis [spitting out of blood from the lungs]”.
Then allergic bronchopulmonary aspergillosis affects 2.5% of patients with asthma, and an estimated 4.8 million people globally. All three diseases are different manifestations of the same fungus, Apergillus fumigatus (with a couple of other aspergillus species also involved in some cases). For details, see:
To help focus attention I’ve added a new fungal genus as a new illustrative planetary protection example. Aspergillus turns out to be a plausible analogue for a new fungal genus from Mars that might be a serious invasive disease of humans.
It’s also an example of something else. Our immune system might also overreact to a novel fungal genus from Mars. This idea of an allergic reaction to life from Mars seems to be new to the planetary protection literature. I followed it up as a result of discovering that many serious effects from Aspergillus in patients with a competent immune system are due to their immune system over-reacting to it.
Our immune system has evolved over millions of years to defend us against Aspergillus. Many parts of the immune system work together to
When our immune system doesn’t spot Aspergillus or responded to it we get invasive aspergillosis, a very serious disease with high mortality as we saw.
When our immune system does spot it, it has to clear the aspergillus microbes from our lungs. However, at the same time it has to avoid over-reacting in a harmful inflammatory response. Otherwise we may get asthma, or worse, allergic pulmonary aspergillosis. I will indent a summary of how this works as “Techy details”
Techy details: Our immune system detects fungi using its pathogen-associated molecular patterns (PAMPs). It likely uses pattern recognition receptors (PRRs) which trigger the immune response. There are different patterns for each of the main fungal genera that affect humans: Candida, Aspergillus and Cryptococcus table 1 of (Antifungal immune responses: emerging host–pathogen interactions and translational implications)
To dampen down the inflammation when it’s not needed - this is a complex finely tuned reaction that involves the inflammation dampening Treg cells and many T-helper cells.
The most important ones for our adaptive immune response to aspergillus that we use to avoid over-reacting are the Th1, Th17, Th22, Th2, Th9, Treg, and Tr1 cells (The multifaceted role of T-helper responses in host defense against Aspergillus fumigatus)
If our immune system faces a novel fungal genus it’s never seen before in all of terrestrial evolution, it will be a major challenge to mount such a finely tuned response
For instance, as a thought experiment, suppose an alternative evolutionary history where our immune system has only ever encountered Cryptococcus. Now we return Aspergillus from another planet. Our immune system won’t be able to see Aspergillus fumigatus (it will have none of those PAMPs from the techy details above).
Now lets try this thought experiment again, Aspergillus is new as before, but our immune system already encountered Candidas on Earth. Now it has some but not all of the PAMPs needed for the introduced Aspergillus.
If it does recognize Aspergillus the T-helper and T-reg responses are unlikely to achieve the fine balance to avoid overreacting with an allergic reaction.
It might be a similar situation to one or other of these scenarios, if we introduce a novel fungal genus from Mars to Earth’s biosphere which has the capability to grow in the environmental conditions it finds inside or on humans.
Here some people will argue that any Martian life will be unable to live at human body temperatures. The sterilization working group argues that terrestrial life wouldn’t be able to survive on Earth at all.
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.
[bolding added for the two examples in brackets]
This has a major omission, polyextremophiles that live in a wide range of extreme environments and can often also live in normal environments. Their own citation, Merino et al., includes one remarkable polyextremophile, amongst many extremophiles that can only tolerate a narrow range of conditions. Planococcus Halocryophilus has a salinity range 0 to 19% and temperature range -15 °C to 37 °C
(Living at the extremes: extremophiles and the limits of life in a planetary context.: table 3)
p. Halocryophilus Or1 was actually isolated from Canadian permafrost (Planococcus halocryophilus sp. nov., an extreme sub-zero species from high Arctic permafrost), likely grows in sub-zero brine veins around soil particles at an ambient temperature of around -16°C. The researchers found it has an optimal growth temperature of 25°C and can continue to grow right up to 37 °C (human blood temperature) tested (Bacterial growth at− 15 C; molecular insights from the permafrost bacterium Planococcus halocryophilus Or1).
The -15 °C in that table isn’t likely to be the lowest limit for growth as p. Halocryophilus Or1 shows metabolic activity down to at least -25 °C which is the lowest temperature tested (Bacterial growth at− 15 C…). . It’s hard to study growth at low temperatures, as it takes 1,000 to 10,000 years for microbes to successfully colonize granite in the McMurdo dry valleys (Growth on geological time scales in the Antarctic cryptoendolithic microbial community). So it’s certainly possible that p. Halocryophilus can grow colonies extremely slowly at −25 °C. It might be able to grow at even lower temperatures as that’s the lowest tested for metabolic activity. So it is a reasonable an analogue for a Martian microbe for temperature tolerance.
I mentioned earlier on that the blue-green algae Chroococcidiopsis is one of our top candidates for a terrestrial life form that could live on Mars if there is water available for it to use.
We don’t know that Martian life is related to us.
Astrobiologists tell us life on Mars may well be independently evolved. iMOST say:
If so, one of the top candidates for an alternative form of biology is mirror life, which everyone agrees is biologically plausible, evolved from scratch from the mirror images of the chemicals used by terrestrial life.
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.
If we could flip a cake in 3D, like reflecting it in a mirror, all the way down to its molecules, we might be able to eat it, like artificial sweeteners, but our metabolism 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)
According to the theory of punctuated chirality, early on as life was just starting to evolve, there were patches of chemicals that worked together with each other in chiral networks which expand converting a non chiral substrate into chiral organics and where two chiral networks of opposite chirality meet there are ways for them to slowly convert each other to the opposite chirality.
There would be many such patches, some of one chirality some the opposite, and they would expand and flip each other back and forth in chirality on an environmental scale, with these flips perhaps frequent in Early Earth (Gleiser et al., 2008a), until one of them got established as the basis for the evolution of life. If so, depending on how the flips went on Mars, life could easily have evolved from chemicals with the opposite chiral bias to Earth life
Our analysis predicts that other planetary platforms in this solar system and elsewhere could have developed an opposite chiral bias.
They predict that in the universe as a whole if an organic is found in a large sample of independently evolved forms of life it should occur in both forms
As a consequence, a statistically large sampling of extraterrestrial stereochemistry would be necessarily racemic on average
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.
Synthetic biologists plan to gradually flip ordinary to mirror life over a period of a decade or so – and will make sure synthetic mirror life is engineered to depend on chemicals only available in the laboratory. They warn escape of mirror life could cause major transformations of the terrestrial biosphere by locking up organics in unusable mirror forms. See: (Mirror-image cells could transform science-or kill us all)
Martian life likely already has the isomerases to metabolize organics of opposite sense, whether it is mirror or normal life - because nearly all organics are either made abiotically locally, or are infall from comets, asteroids and interplanetary dust, with organics of both senses.
Eventually terrestrial microbes likely develop isomerases to metabolize mirror life, but higher life couldn’t evolve so quickly. The outcome is a mix of normal and mirror organics. In Kasting and Church’s worst case scenario 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 (Mirror-image cells could transform science-or kill us all)
In this worst case I don’t think humans would go extinct even on the centuries timescale. We could enclose large areas of Earth with its tropical jungles, coral reefs etc, in habitats similarly to Biosphere 2.
And there might well be things see can do to help terrestrial microbes win the evolutionary race with the imported mirror life.
But it’s far better not to do the experiment.
We will only know if we are in the scenario of a Mars with mirror life if we go look for it and find it.
If we are in that scenario, then we would likely decide as a civilization that we must never return the Martian mirror life back to Earth.
So, to help focus attention on the potential for adverse effects on the environment, the very worst case we could return microbes that could transform Earth’s biosphere in ways we can’t predict.
These are worst cases not likely cases.
But as with house fires, and smoke detectors we do need to look at worst cases. We can’t protect Earth properly if we only look at the most optimistic scenarios.
We can’t rely on the same risk-benefit calculus for release of SARS and for release of mirror life.
Some synthetic biologists say we need a level of assurance for synthetic biology far higher than for any biosafety laboratory. Schmidt said:
… maybe [1 in 100,000,000,000,000,000,000] is more than enough …
The probability also needs to reflect the potential impact, in our case the establishment of an XNA ecosystem in the environment, and how threatening we believe this is.
The most important aspect, however, is that the new safety mechanism should be several orders of magnitude safer than any contemporary biosafety mechanism
(Xenobiology: a new form of life as the ultimate biosafety tool.)
[In this quote XNA refers to life based on a different informational polymer from DNA. Similar remarks would apply to mirror life]
The same precautions may be needed for returning alien biology from another planet.
This is NOT something that NASA mission planners can decide for the rest of humanity. This is NOT something we can decide using the scientific method.
We need a wider discussion here to work out the necessary level of assurance if there is indeed a potential for returning mirror life from Mars. This is one of the NEPA’s central requirements for a valid EIS.
Agencies shall prepare environmental impact statements using an interdisciplinary approach that will ensure the integrated use of the natural and social sciences and the environmental design arts … The disciplines of the preparers shall be appropriate to the scope and issues identified in the scoping process
§ 1507.2 [links directly to legal text]
Mars sample return studies emphasize the need to involve the public early on, not just in the USA, but through fora open to representatives from all countries globally because negative impacts could affect countries beyond the ones involved directly in the mission (Ammann et al, 2012:59)
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)
The public weren’t involved early on in that way. Not only that, the few in the public who did discover NASA’s request for public comment weren't given the opportunity to comment on a scientifically valid EIS.
We can’t rely on the same risk-benefit calculus for release of SARS and for release of mirror life, without legislative / executive / public involvement to decide if this is what we should do.
The theologian Richard Randolph put it like this, from a Christian perspective:
The risk of back contamination is not zero. There is always some risk. In this case, the problem of risk – even extremely low risk – is exacerbated because the consequences of back contamination could be quite severe. Without being overly dramatic, the consequences might well include the extinction of species and the destruction of whole ecosystems. Humans could also be threatened with death or a significant decrease in life prospects
In this situation, what is an ethically acceptable level of risk, even if it is quite low? This is not a technical question for scientists and engineers. Rather it is a moral question concerning accepting risk
(Chapter 15, God’s preferential option for life: a Christian perspective on astrobiology)
Several dozen distinct members of the public expressed views that suggest they would be in support of Sagan’s quote, on a not very widely publicised EIS. Nine commentators specifically mention unprecedented harm.
This figure of 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 all the comments with the ones expressing comments similar to Sagan’s view in bold.
Some of the comments were very detailed with attachments.
Thomas Dehel quoting from an interview he did with Gill Levin 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.”
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”
Chester Everline, co-author of your handbook on probabilistic risk assurance:
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).
My own final comment, in 14 points ending:
Let's make this an even better mission and SAFE for Earth.
National Research Council in 2009. This is for large scale harm to humans and the envioronment.
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
The difference between “appears to be low, but is not demonstrably zero” and “near-zero probability” may seem subtle but it has major legal consequences. This is what the sterilization working group said:
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.
All previous studies have said numerous laws to protect Earth’s environment would be triggered by a Mars sample return and other agencies such as the CDC, Department of Agriculture, most recently, from 2019. Updating Planetary Protection Considerations and Policies for Mars Sample Return (with your former planetary protection officer Cassie Conley as co-author)
NASA themselves are mandated to consider such matters as:
● impact on the environment,
● impact on the oceans,
● impact on the great lakes,
● escape of invasive species,
● lab biosecurity against theft
See: page 3–3 of NASA Facilities Design Guide
Yet there is no discussion of these matters in your draft EIS, only on environmental effects in the immediate area where the sample capsule hits the Earth.
Just by omission, that these things are not considered, it shows that authors of the EIS are of the view that “near - zero” means there is no need to consider wider environmental effects even under these direct obligations for NASA as a government agency under numerous executive orders.
US agencies that would get involved include:
This is a joint ESA / NASA mission. The papers I found don’t go into this. But ESA are closely involved as they are responsible for fetching the samples from Mars and returning them to Earth.
So, the legislation of ESA member states would seem relevant. That includes the UK, the EU and other member states and cooperating states. Se (Member States & Cooperating States )
With the EU involved,
Also the UK and many other member states of ESA are parties to the Espoo convention. List of parties: UNTC
Under that convention they would need to consult with each other on all major projects that can have an effect outside of their own boundaries - which would certainly apply to a Mars sample return release of life that transformed the biosphere (Environmental Assessment - Espoo Convention)
It seems unlikely worst case scenarios would be ignored as the legal proceedings continue. So, for any Mars sample return mission for any country, at some stage, international agencies may get involved like
Many international treaties and domestic laws of other countries are also likely to be relevant. Race and Urhan et al summarize some of these potential legal ramification see:
In the USA, the Environmental Protection Agency partners with the United Nations Environment Program (UNEP), and Arctic Council, so they’d likely get involved.
Indeed, with mirror life from Mars as an example worst case scenario, there would be few aspects of human life not relevant in some way in discussions of the very worst-case scenarios.
In this way, a scenario of mirror life can help focus attention on our responsibilities to protect Earth’s biosphere. This doesn’t happen if we focus exclusively on best case scenarios with no harm or near zero possibility of harm to humans or Earth’s environment, even if the best case scenarios may indeed be likely ones. Returning to what John Rummel said:
People have to have some kind of respect for the unknown. If you have that respect, then you can do a credible job, and the public is well-served by your caution.”
(Controversy Grows Over whether Mars Samples Endanger Earth)
I suggest in this case respect for the unknown should involve considering the scenario of mirror life, for as long as it remains an astrobiologically plausible scenario for Mars.
The analogy of a house fire helps again. If we pay close attention to a scenario of a house fire it helps us install smoke detectors properly. If we think a house fire is impossible, we might leave smoke detectors out altogether.
As the legal process continues, surely there would be open public debate about these scenarios, and if the discussion expands in this way, potentially it might lead to much wider involvement in the international community. It would be necessary to convince the public, and interested experts in all these agencies that this is a safe mission and that all their concerns have been answered.
In short, great care is taken to make sure Earth is kept safe.
The draft EIS says they would use many of the basic principles of a Biosafety level 4 facility (BSL-4):
Nevertheless, out of an abundance of caution and in accordance with NASA policy and regulations, NASA would implement measures to ensure that the Mars material is fully contained (with redundant layers of containment) so that it could not be released into Earth’s biosphere and impact humans or Earth’s environment.…
The material would remain contained until examined and confirmed safe or sterilized for distribution to terrestrial science laboratories. NASA and its partners would use many of the basic principles that Biosafety Level 4 (BSL-4) laboratories use today to contain, handle, and study materials that are known or suspected to be hazardous.
But the ESF set requirements well beyond an BSL-4 in 2012
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
This is how the 2012 ESF report explained its decision at the time study (Ammann et al, 2012:3):
The value for the maximum particle size was derived from the NRC-SSB 1999 report ‘Size Limits of Very Small Microorganisms: Proceedings of a Workshop’, which declared that 0.25 ± 0.05 μm was the lower size limit for life as we know it (NRC, 1999). However, the past decade has shown enormous advances in microbiology, and microbes in the 0.10–0.15 μm range have been discovered in various environments. Therefore, the value for the maximum particle size that could be released into the Earth’s biosphere is revisited and re-evaluated in this report. Also, the current level of assurance of preventing the release of a Mars particle is reconsidered.
So NASA’s BSL-4 recommendation goes back to the science of 1999 and a lot has changed in our understanding since then
Text on graphic: ESF study requires at most one particle released from the facility of ANY SIZE above 0.01 microns and 100% CONTAINMENT ABOVE 0.05 microns - this requires breakthrough technology as the methods used by current air filters couldn't achieve it
Below maximum penetrating particle size: Filters rely on jostling of particles by air molecules until they hit a fiber by chance.
Above MPPS: Particles are comparable in size to the gaps between fibers and are stopped by hitting them.
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 100% requirement would seem to need some new breakthrough technique rather than incremental changes such as more layers of filters or varying the spacing as those couldn’t get it all the way to 100% containment of such small particles.
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
SEM of a bacterium that passed through a 100 nm filter (0.1 microns), larger white bar is 200 nm in length
A self contained viable mirror cell from Mars might potentially be as small as a ribocell. Research since 2012 has made this seem increasingly plausible.
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. Here for instance is a summary by Rummel et al.
If there were a life-form on Mars based on other than carbon-containing molecules, the energies holding such molecules together would not be much different than those for proteins and polynucleotides.
Hence, bond breakage by heat or gamma radiation should be similar for Earth and Mars life forms, and sterilization conditions for Earth microorganisms should eradicate microorganisms of similar size from Mars.
There is no absolutely optimal approach to decontamination under these circumstances, but enough is known about the relationships among organism size, repair mechanisms, and survivability, that the maximum survivability of any martian organisms can be estimated with some confidence.
Page 10 of (A draft test protocol for detecting possible biohazards in Martian samples returned to Earth)
This idea is similar but it’s to use an air-flow incinerator instead of an oven. Would an air incinerator be sufficient to contain the very small ultramicrobacteria, possibly ribocells, and extraterrestrial biology?
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)
These might be effective as a way to contain very small cells, but we need to be aware that they are not rated as such or tested to do this. We have never had to contain ultramicrobacteria in any biosafety laboratory and we have no technology designed to do this.
If NASA with to explore this, it still needs a new EIS.
Once we know what needs to be achieved, NASA need to look into technology.
Then, I think once it goes through WHO, CDC etc there may well be:
It is too soon to propose a new technology before we know the requirements or the testing methods or who will evaluate it and how. However we can look briefly at some of the issues we would need to consider.
The NIH guidelines for research involving recombinant or synthetic nucleic acid molecules specifies that these air incinerators need to be tested against a challenge aerosol of hardy spores, either b. subtilis var niger spores, or b. stearothermophilus spores (NIH guidelines April 2019).
However, for a Mars sample return, it also has to contain potential Martian life potentially more resilient than terrestrial life after millions of years of evolution in the extreme conditions on Mars. It may have:
Then in addition
By the ESF requirement, it has to contain
Then Martian microbes could use a more resilient backbone than DNA for its informational biopolymer. In one experimental test of PNA heated for 150 to 200 ms
See : Fig 10 of (Thermal stability of peptide nucleic acid complexes)
In a test of melting for 200 ms,
See : Fig 4 of (Thermal stability of peptide nucleic acid complexes)
Mars could have more stable informational polymers through an accident of evolution, or through adaptation to ionizing radiation, or adaptation to high temperatures or both. Mars had subsurface hydrothermal systems in the recent past, and they may well be present today as well, and may well be a refuge for surface life at times when the surface is less hospitable.
In short, an airflow incinerator may be part of a future solution, but it couldn’t be added in at the last minute in an ad hoc way to “fix” the draft EIS.
There would be a lot of preliminary work needed before it could be considered as a solution. The EIS would need to restart with a new technology review based on examining whether such technology could be used to contain an alien biology to the required level of assurance. There seem to be many things that such a review would need to consider.
The standards would need to be developed with the same level of care that was used to develop the standards for BSL-4 facilities and Biosafety class III cabinets.
Perhaps this will be an option in the future. However, it is not clear why we would do this for NASA’s mission, since there is a far easier approach, to sterilize the samples before they are returned to Earth.
If NASA do pursue this approach of an air-flow incinerator, they should by NEPA requirements also consider reasonable alternatives such as presterilizing samples before they return to Earth.
However you CAN turn this into a mission that is 100% safe for Earth and that achieves all the same science objectives and indeed achieves far more, by sterilizing all Perseverance's samples before they reach Earth. 8 commentators suggested this in the first round of public comments but you haven't considered it in the draft EIS. I suggest it deserves attention.
Sterilization will have virtually no impact on the geological science studies as you yourself concluded. As for astrobiological studies, even past organics with 100 parts per billion as in our least exposed Martian meteorites would have that reduced to 0.1 parts per billion of recognizable organics after just 20 million years of surface exposure. The organics aren't destroyed in this process but bonds are broken and reformed to the extent that they are unrecognizable. Perseverance can't detect the exposure age of the rocks it samples, and has virtually no chance of returning samples with interesting evidence of past life organics.
You have another option here to maintain your world-leading role in planetary protection, with no risk of harm to Earth and to provide an example for other space agencies to follow.
This is the option of a pre-sterilized sample return. This is a simple way of keeping Earth 100% safe that other space agencies and private space can copy easily. Your draft EIS didn’t even look at this option although I and several others recommended it in the first round of public comments.
NEPA requires you to look at reasonable alternatives.
(a) Evaluate reasonable alternatives to the proposed action, and, for alternatives that the agency eliminated from detailed study, briefly discuss the reasons for their elimination.
(b) Discuss each alternative considered in detail, including the proposed action, so that reviewers may evaluate their comparative merits.
§ 1502.14 [links directly to legal text]
The samples can be sterilized in a satellite resembling those in Geostationary Earth Orbit but in a higher orbit with no risk of contamination of either Earth or the satellites in GEO. Other missions could use the same satellite for sterilization for their missions too. The sample tubes wouldn’t need to be opened, just sterilize the whole sample.
This will have minimal impact on geology. From your own EIS you don’t expect any present-day life.
I and seven others made this suggestion in the first round of public comments. But you didn’t look at it.
Meanwhile, it turns out your permitted forward contamination will make it impossible to detect biosignatures of past life even in samples with only 6 million years of surface exposure. That is enough to reduce recognizable biosignatures from 100 ppb as found in a Mars meteorite with only 2 million years of ionizing radiation exposure to 0.1 ppb (not destroyed, but broken up and transformed into other usually short molecule organics).
That is below your 0.7 ppb per biosignature of forward contamination by terrestrial life which you think you have achieved.
That is far less than the 80 million years exposure age of the Curiosity Cumberland mudstone sample. Though it’s possible Jezero crater has samples with younger exposure ages than that, Perseverance doesn’t have the capability to measure exposure ages in situ.
Text on image: Example of how design decisions for Perseverance were based on engineering and geology rather than astrobiology.
This tube was used to collect the first sample from Mars.
For a geologist, it is exceptionally clean, at most 8.1 nanograms of organics and at most 0.7 nanograms per biosignature.
For an astrobiologist, 0.7 nanograms per biosignature is enough to fill at least 7,000 ultramicrobacteria with just that biosignature, e.g. glycine, or DNA (maximum volume 0.1 cubic microns per ultramicrobacteria)
Astrobiologists need 100% clean sample containers with no organics. Their life detection instruments designed for in situ searches on Mrs can detect a single amino acid in a gram.
For engineers, sterilization would add an extra mission critical failure point because they would need to open the sterile container for the tube on Mars.
Sterilizing the samples in situ eliminates the risk of the general public being opposed and conspiracy theories. It also eliminates the issue of the presidential directive on large-scale effects or legal challenges to the EIS.
It makes no difference to cost as it removes the cost of a new biosafety laboratory that NASA doesn’t have - and it adds the cost of a small robotic satellite similar to the ones in GEO to sterilize samples before they return to Earth which is roughly similar in cost.
Also it removes the need for a heavy aeroshell, so it turns out to have almost no difference on the return mission too.
Also, as we saw, it has likely virtually no impact on science return.
I also make suggestions for a way to greatly increase the science return by returning samples of the surface dust, dirt, atmosphere, and pebbles in a CLEAN container sent there in the ESF fetch rover.
This would be returned not to Earth but for remote study in the same satellite above GEO that we have for sterilizing the Perseverance samples.
We would study the bonus samples using instruments already designed for in situ searches for life biosignatures and processes on Mars. In this way also we build up a capability in space to anlayse future samples returned from Mars and elsewhere in the solar system.
This would be minimal cost for NASA as the instruments would be funded by universities.
Humans go nowhere near the satellite (human quarantine can’t keep out mirror life or fungal pathogens of crops or fungal diseases that only affect some people).
We can return subsamples of the dirt, dust, and pebbles to Earth but we would do 100% sterilization of those samples. We can’t do safety testing to a high level of assurance even for samples in a clean container. Destructively test 10,000 grains of sand and the 10,001th grain could have a microbe imbedded in a crack that we never noticed.
We would study unsterilized samples in a safe orbit above GEO until we understand what’s in the samples very well, then it is for us to assess whether to continue to keep them in orbit. It may take multiple missions to Mars before we understand it well enough to be sure that samples can be returned unsterilized.
We do need to be prepared for the possibility of a discovery of great interest, such as mirror life, that would mean we can NEVER return uncontained unsterilized samples to Earth. That is why we do all this. Because there is a significant, likely small possibility that Earth DOES need to be protected.
I cover the main points in my final comment to your draft EIS
I recommend this draft Environmental Impact Statement is stopped, and a new one prepared after doing the necessary size limits review, and fixing whatever led to its many errors.
1. The BSL-4 recommendation in this EIS is out of date, based on science of 1999.
2. This EIS does not mention the most recent Mars Sample Return study from 2012 by the European Space Foundation which reduced the 1999 size limit from 0.2 microns to 0.05 microns to contain ultramicrobacteria and required 100% containment at that size.
3. A BSL-4 is not designed to this standard. In recent reviews of filter technology, I find NO AIR FILTERS with that capability – and no evidence anybody is working on them. Air filters for larger particles remove some of these very small particles kicked out of the airstream by jostling of air molecules by Brownian motion but can't remove all. It is an unusual requirement.
4. NASA haven't responded to my comment in May which alerted them to this omission. They still don't cite the ESF study. Also, the ESF said their limit needs to be updated periodically. An update is certainly due a decade later.
5. The EIS has an overnarrow scope in the Purpose and Need section - it requires samples to be returned unsterilized to terrestrial labs for "safety testing". This won’t work. NASA believe they reduced the most abundant biosignatures to 0.7 nanograms per gram of returned rock sample – this guarantees a positive test. There will be no way to know if tubes contain safe terrestrial life or potentially unsafe martian life.
6. This narrow scope improperly excludes the reasonable alternative of presterilizing samples before they reach Earth's biosphere - which achieves virtually the same science return and keeps Earth 100% safe. By a 1997 case in the 7th circuit this alone probably invalidates the EIS.
7. The high levels of forward contamination make astrobiology almost impossible. I recommend bonus samples of dirt, dust and atmosphere collected in a STERILE container with no terrestrial organics, brought to Mars especially on the ESA fetch rover.
8. I recommend returning these bonus astrobiology samples to a safe orbit above GEO where they can be tested for life
9. The EIS’s reasoning for no significant environmental effects contradicts the conclusion of the NRC study from 2009 which they do cite, which says the risk of even large-scale impacts on human health or environment is likely low but not demonstrably non zero. It also warns against the meteorite argument that they use. I found multiple errors in my analysis.
10. Returned life COULD be harmful. Example, fungi kill crops, other life and sometimes immunocompromised humans. Botulism, ergot disease, tetanus, all are the results of exotoxins not adapted to the lifeforms they kill, similarly some algal blooms kill dogs and cows that eat them. BMAA misincorporated for L-serine causes protein misfolding and is a neurotoxin implicated in some cases of the disease that affected Steven Hawking - an alternative biochemistry may have many different amino acids similar enough to terrestrial amino acids to be misincorporated. Or perhaps martian life evolved from scratch from mirror chemicals as mirror life - the effect on our biosphere can't be predicted. I give many such examples in my preprint. Or it could be harmless like microbes from a terrestrial desert, or indeed beneficial. But we DON'T KNOW. So we need to find out first.
11. What matters for invasive species are the ones that can’t ‘get here, like starlings that can't cross the Atlantic rather than barn swallows. The freshwater diatom Didymo is invasive in New Zealand and can't get from one freshwater lake to another without humans. A microbe adapted to briny seeps on Mars and to spreading in dust storms shielded from UV, may well not get to Earth in a meteorite, while a sealed sample tube including Martian atmosphere, at Mars atmospheric pressure, is like a mini spaceship.
12. Quarantine of humans can’t keep out a fungal disease of crops, mirror life etc.
13. So any unsterilized samples will need to be studied remotely via telerobotics which also greatly reduces forwards contamination (issues with filtering ultramicrobacteria will go both ways).
14. astrobiologists now have tiny instruments that can go from sample preparation to life detection, even to a gene sequence[r], operated remotely on Mars. They could send hundreds of these in each 7 ton payload of the Ariane 5 to above GEO.Let's make this an even better mission and SAFE for Earth.
Thanks!
