This is a presentation for my preprint. I plan to submit it to the astrobiology journals in spring 2021. The paper is here: https://osf.io/s8gcn/
[WORK IN PROGRESS PLEASE CHECK BACK LATER]
NASA's Perseverance is already on the way to Mars. In collaboration with ESA, they plan to return unsterilized samples to study in a Mars receiving facility in 2031.
NASA haven't yet started the legal process or the build for the sample receiving facility.
When researching for my paper I discovered that we don’t yet have the technology to fit the specifications for the ESF sample return study in 2012.
The European Space Foundation study summarizes their conclusions in this figure (Ammann et al, 2012:14ff). :
Figure 3: ESF summary of containment requirements
Figure 7: screenshot from the ESF report
So the release of a single unsterilized particle larger than 0.05 microns is not acceptable under any circumstnaces.
This was because of a discovery that bacteria in starvation mode can pass through a 0.1 micron nanopore as well as a theoretical estimate of the minimum possible diameter of terrestrial microbes which came to a similar size.
Figure 2: SEM of a bacterium that passed through a 100 nm filter, large white bar is 200 nm in length (Liu et al, 2019).
HEPA and ULPA filters are not tested for particles so small. So a modern biosafety laboratory is not able to contain such tiny microbes.
Smaller nanopores would of course filter them out, but it's a case of making them into a filter.
The viruses for COVID-19 are in the same size range. HEPA filters in ICU units work by containing the larger droplets and reducing the viral load to the point where our innate immune system can prevent infection.
A six layer experimental filter for COVID-19 viruses is able to keep out 88% of particles at 0.05 microns. This filter is not available commercially.
Figure 8: schematic illustration of coronavirus attached to a 60 nm diameter carrier droplet Their test filter can filter out 88% of particles at 50 nm and larger. This is not sufficient for the ESF standard which requires the filter to remove all particles without exception at this size. from (Leung et al, 2020).)
So the technology for the facility doesn't exist.
The Euro Cares design for a sample receiving facility has a typo. In this screenshot, their cite 10 is to the ESF study.
Figure 6: screenshot from the EURO-CARES study
The ESF study does have a one in a million requirement, but this is for an unsterilized particle ≥ 0.01μm or 10 nm (Ammann et al, 2012:48).
The one in a million requriement is also the probability for release of a single particle for the lifetime of the facility rather than a probability per particle. This can be reviewed but the 0.05 micron size is not acceptable under any circumstances.
By 2012 we also knew that gene transfer agents can transfer antibiotic resistance to unrelated microbes in sea water overnight, far faster than expected. These are in the size range of 0.03 microns upwards.
The ESF study recommended periodic review because of the dramatic reduction from 0.25 to 0.05 microns in just three years and this GTA discovery.
So what might such a review discover today?
It's impossible that modern life arose in one go because it is all connected together in a circle. Enzymes are needed to transcribe DNA into mRNA, but these enzymes are made from mRNA using ribosomes, and can't be made until the DNA can be transcribed (see . Molecular Expressions Cell Biology: Ribosomes)
Ribosomes in turn are made of ribozomal RNA which is transcribed from DNA, as well as protein sub-units made from mRNA using the ribosomes themselves (see The Road to Ribosomes: Filling Potholes in the Export Pathway)
This must have evolved from something simpler. One suggestion for early life has only 5 genes, no proteins, no DNA, and instead of ribosomes it has ribozymes which are made up of fragments of RNA without any proteins.
By one estimate such early life, when starvation limited, could pass through a 0.02 micron filter.
Although simple it could co-exist in a shadow biosphere especially if it consisted of an alien biology such as mirror life that most terrestrial life can’t attack, or was very small, unnoticed by larger life.
This ressearch actually goes back to 1999, before the 2012 review:
Figure 11: Panel 4 from the limitations of size workshop measured one of these putative ultramicrobacteria from Figure 6B of (McKay et al, 1996:928) and found a dimension of 120 nm long and 10 nm in diameter.
However there is much more research on RNA world life now than there was in 2012. A new review 8 years later might well revise the minimum size down to 0.01 microns.
We can’t start the build yet, because we need to do the review of the size limits first. We then have to develop the new technology before NASA know what to build.
That would add several years already.
However NASA is a proponent in the legal process. By the precautionary principle it is the proponent that has to prove that what they will do is safe, rather than those who are concerned that their measures might be inadequate.
So NASA has to prove that what it proposes to build will indeed protect Earth. That is the very matter to be examined in the legal process.
NASA has a requirement that the proponents for a build have to complete an "Enterprise Architecture Review" and an "Enterprise Service Review" before they unlock funding and start detailed planning. NASA need to know what they will build and how to service it.
However, NASA won't know what they will build and their designs can't be approved until they have the outcome of the legal process.
This doesn't seem to have been discussed in the planetary protection literature so far.
If I have got this right then this makes the earliest legal return 2040, But the delays involved due to technology requirements and complications of the legal process could easily take this through to 2050.
Apollo 11 returned samples only 7 years after Kennedy's speech but those were simpler times. The guidelines were published on the day of launch, under the rather weak Outer Space treaty. There was no legal process, the legality was not challenged, and the science was primitive by modern standards.
We now know that the Moon is sterile but at the time Sagan had published a paper hypothesizing that there could be life in trapped layers a little way below the surface. Organics could have survived from the early solar system protected from cosmic radiation and solar storms and at the same time temperatures are just right for liquid water.
Sagan published a paper in 1961 suggesting that there could be liquid water suitable for life just a few meters below the lunar surface.
As the lunar atmosphere escaped to space, surface temperatures and radiation fluxes became more extreme, and meteoritic debris began covering the synthesized organic matter, it is only reasonable- to anticipate that any indigenous organisms took to a subsurface existence.
It is remarkable that the depth at which surviving lunar organic matter is expected to be localized (section ll) is just the depth at which temperatures appear to be optimum for familiar organisms (section IV). At such temperatures and depths, some moisture should be expected, arising from meteoritic and organic bound water. Watson, Murray and Brown (1961) have recently pointed out that ice could have been retained on permanently shaded areas of the Moon. These circumstances provide all the survival requirements of many terrestrial organisms -water and other metabolites, appropriate temperature, and negligible radiation.
That autochthons evolving with the changing environment could also survive under these conditions is far from inconceivable. A somewhat analogous case is the anaerobic microflora which inhabit terrestrial petroleum deposits. It follows that the possibility of an extant lunar parabiology must not be dismissed in as cavalier a manner as it has been in the past. As we shall see in section VI, it is likely that relics of past lunar organisms, if any, could be preserved indefinitely if sequestered well beneath the protective cover of the upper lunar surface material.
Thus, neither should the possibility of lunar paleontology be overlooked. It is probably unnecessary to remark that the study of any extraterrestrial organism will have the deepest influence on the fundamental problems of biology. Even if the chances of success are small, attempts should be made to detect lunar subsurface autochthons, both living and dead.
Sagan, C. Organic matter and the Moon., 1961, National Academy of Sciences.
Sagan’s hypothetical liquid water layer on the Moon
Diagram from: Shyama Narendranath schematic diagram showing the cross section of the upper layers of the lunar crust (re-drawn from [Hiesinger and Head, 2006])
We now know that the lunar regolith is sterile. However in the case of Mars we know there ARE layers of liquid brines there that form briefly at night in winter
Figure 22: Indirectly detected surface brines mapped according to time of day and time in the Martian year. The light blue patches are liquid on the Martian surface and the dark blue patches later in the day are liquid at a depth of 5 cm.
Black lines frame the time when water is stable. Sunrise and sunset times shown with the red lines.
Although the Curiosity brines would not be habitable in their native form, life can create microhabitats. Nilton Renno observed that life in a biofilm could retain the water into the daytime in warmer conditions suitable for life.
Over billions of years Martian life could have evolved to do this, and it could also make use of the chaotropic agents such as the perchlorates to speed up their metabolism at low temperatures. These work by disrupting hydrogen bonds leading to faster chemical processes.
Shows temperature fluctuations in red
The labelled release (in black) is almost synchronized with the temperature fluctuations, but delayed by two hours.
Also, the labelled release response is smoother. A chemical reaction would follow every variation in the temperature (shown in red) exactly.
From Joseph Miller, Periodic Analysis of the Viking Lander Labeled Release Experiment.
The main things are
Joseph Miller, interviewed for USC news (he is a researcher at USC), said
“To paraphrase an old saying, if it looks like a microbe and acts like a microbe, then it probably is a microbe. The presence of circadian rhythmicity and a high degree of mathematical complexity or order in the LR data most likely means Viking discovered microbial life on Mars over 35 years ago.
... “This research is not a smoking gun .A smoking gun would be taking a picture under a microscope of Mars bacteria. But the case is getting stronger. We know there is subsurface water ice and perhaps liquid water in regions that seem to release methane gas into the atmosphere. Water is necessary for life, and methane is a potential signature of biology. There’s enough circumstantial evidence that strongly suggests NASA or the European Space Agency should consider explicit life detection experiments on Mars.”
Figure 26: excess of oxygen in spring to summer and deficit in winter over the expected seasonal variation as measured by Curiosity.
Credits: Melissa Trainer/Dan Gallagher/NASA Goddard (Shekhtman, 2019)
Figure 27: Weak inverse correlation of oxygen to argon ratio with dust optical depth, less oxygen is produced when the atmosphere lets less light through, Figure 59 of Supporting information for (Trainer et al, 2019)
Optical depth of 0.3 means 74% of the light is let through. Optical depth of 1.1 means 33% of the light is let through.
We have no samples of lunar dust on Earth never mind dust or brines from Mars.
The Martian meteorites we have come from at least three meters below the surface. Though they could have past life this layer is thought to be sterile almost everywhere on Mars.
Carl Sagan's remark that we cannot take even a small risk with a billion lives. (Sagan, 1977:130)
The likelihood that such pathogens exist is probably small, but we cannot take even a small risk with a billion lives.
The studies don’t seem to consider really large scale effects like that. However though this is not given much coverage in the planetary protection literature it is a central question in synthetic biology.
The risk of releasing mirror life into the environment is of a qualitatively different order from releasing a pathogen such as anthrax.
Sample return studies have a remit to find a way to return a sample safely to Earth.
In the legal process, however, with NASA as a proponent, there is no such remit, and the objective is to find out if the sample can be returned safely.
In the case of Mars then we already know that there are liquid brines there, discovered by Curiosity indirectly in the sand dunes. Though very cold they could be habitable to biofilms that retain the water through to daytime.
We don't have any sample of dust from Mars and the only dust from the Moon is from sample returns. If any dust has got to Earth from Mars it got thoroughly sterilized on the journey.
Our Mars meteorites all come from at least 3 meters below the surface, and most of present day Mars is believed to be sterile at that depth. There has been no opportunity for surface Martian life to get to Earth in recent times.
Also most terrestrial life, including most photosynthetic microbes, would not survive transfer from Mars to Earth.
We don't know why Earth doesn't have mirror life, with everything reflected in a mirror and the DNA spiraling in the opposite direction.
Perhaps Mars has both forms of life. If so, the independently evolved mirror life might not have evolved the ability to get to Earth even if the normal life did get here.
Not only astronauts need quarantine. With the Apollo samples, eleven technicians had to be quarantined after a cut was discovered in one of the sample handling gloves.
So we need to consider quarantine for the NASA / ESA sample return.
For an example of the primitive science at the time of Apollo, the navy frogman "sterilized" the astronauts by swabbing the outside of their biological isolation garments with bleach, which doesn't destroy spores. He then dropped the swabs into the ocean.
There was an earlier breach when the astronauts opened the door of their capsule. Some of the fine lunar dust suspended in the air in the capsule would have got into the sea at that point already. The astronauts reported that it smelt like gunpowder. Indeed some of the dust probably escaped when the interior of the capsule was vented during the descent.
NASA didn't have the legal authority to quarantine the astronauts and this was done under the direction of the Surgeon General. The legality of this is not tested.
Apollo 11 returned samples in 1969 only seven years after Kennedy’s speech in 1962.
However those were simpler times. Their science was primitive by modern standards. It was done under the very weak article IX of the Outer Space Treaty.
States Parties to the Treaty shall pursue studies of outer space, including the moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.
The modern laws to protect Earth’s environment didn’t exist.
The guidelines were published on the date of launch of Apollo 11, and there were no legal challenges. For instance NASA didn’t have the legal authority to quarantine the astronauts. They got the Surgeon General to oversee quarantine for them, but the legality of that is not tested.
This was not challenged at the time and the guidelines have now been rescinded. So there is no precedent, and there was no legal process.
When a small cut was found in one of the gloves while examining one of the samples returned by Apollo 12, 11 technicians had to go into quarantine (Meltzer, 2012:241).
So we need to look into this for a sampel return
The Apollo mission is now regarded as a valuable lesson in how NOT to do it. My main source here is "When Biospheres Collide: A History of NASA's Planetary Protection Programs. "
When the astronauts opened the capsule door to Apollo 11 for the navy frogman to throw in their biological isolation garments, some dust would have got into the sea already at that point.
Navy Frogman Clancy Hatleberg wearing a biological isolation garment opens the capsule door at 5:25 into this video to throw the garments in for the astronauts to don.
He then swabbed the astronauts down with bleach and threw the swabs into the ocean. Bleach is not able to destroy microbial spores.
A new review would also consider the researches of synthetic biology, which has made huge advances in the last 8 years.
Hachimoji DNA has four extra synthetic bases and is inheritable. It was able to make an enzyme that makes spinach fluoresce green.
. Hachimoji DNA and RNA: A genetic system with eight building blocks
Some synthetic biologists think that the "gold standard" of a one in a million chance of escape from a biosafety laboratory might not be good enough for synthetic life. This again predates the 2012 review, this is from 2010:
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
Synthetic biologists are taking extreme care. With Hachimoji DNA, the extra bases were designed so that it can only reproduce when supplied by chemicals only available in the laboratory.
We have also made the first steps towards making a synthetic mirror life cell. We now have mirror image DNA polymerase to coordinate copying mirror DNA.
. Mirror-image enzyme copies looking-glass DNA
Synthetic biologists like George Church are hoping eventually to make a complete mirror synthetic cell.
(Hutzler et al, 2017:5). However there was some
The planetary protection literature so far doesn’t seem to have considered the possibility of return of mirror life, at least not in any depth. I have not been able to find any previous cites yet (if you know of anything do say).
We don’t know why Earth doesn’t have mirror life. If Mars has both normal and mirror life, the mirror life is likely to be able to metabolize the normal life on Mars and so could also metabolize terrestrial biology. Also Mars has a constant infall of organics from comets, asteroids and interplanetary dust which has organics in both normal and mirror image form, so it would be an evolutionary advantage to be able to metabolize both chiralities.
Some terrestrial microbes are able to metabolize mirror biology, but it is a rare capability.
So, we can expect any Martian mirrror life to be able to eat normal life. But most normal life can’t eat mirror life.
Mirror life - challenges from synthetic biology
No viruses have evolved to attack mirror life. The synthetic biologist George Church put it like this:
“Viruses can’t touch a mirror cell,”
He explains that a virus usually enters the cell using a mechanism that wold be thwarted by the wrong-handed molecules.
Then the virus needs to take over the cellular machinery to make mor ecopies of itself, but it would be unreadable by the cells internal factory for making proteins to build more of itself.
If mirror life was able to eat normal life, the result is not pretty. Most terrestrial life would be unable to metabolize most mirror organics such as starches, proteins, and fats giving it a huge competitive advantage.
As the science journalist . John Bohannon put it:
Mirror cells would slowly convert edible matter into more of themselves. Anything that ate them wouldn’t be able to digest the mirrored molecules—they’d pass right through predators’ guts. And as the mirror cells excreted waste and died, the accumulating material would be like a self-generating oil spill with nothing to clean it up. . Mirror-Image Cells Could Transform Science — or Kill Us All
Jim Kasting, a climate scientist, and expert on the carbon cycle put it like this:
It would quickly consume all the available nutrients. This would leave fewer or perhaps no nutrients for normal organisms.
[after half of Earth’s CO2 is removed from the atmosphere]
All agricultural crops other than corn and sugar cane would die.
. Mirror-Image Cells Could Transform Science — or Kill Us All
To prevent this needs something better than a biosafety laboratory with a one in a million chance of release. They might do it by ensuring that any synthetic mirror life depends on chemicals not available outside the laboratory.
This also is likely to lead to more stringent requirements.
With the archaea we have a whole domain life that is not pathogenic for humans except possibly for tooth decay and minor effects. Extraterrestrial life might be harmless to us or even beneficial.
But we don’t know until we study it.
There were humans already in the Americas. There are no humans on Mars.
It was possible to grow crops in the Americas using similar methods to the methods used for agriculture in Europe. To grow crops on Mars requires a much more difficult and expensive agriculture than on Earth. Even a terrestrial greenhouse would just explode from the tons per square meter outwards pressure and the temperatures at night often are so low you get dry ice frosts.
Just to go outside your habitat requires a space suit, a huge difference from Earth. No radically new technology was needed to go outside your house in the Americas.
Early Mars colonists had profits immediately from fur trading. There will be no profits on Mars for early colonists, nothing you can send back to Earth for a profit.
However if we find life on Mars, especially a radically new biology such as mirror life, this could be a big financial incentive to set up settlements in orbit around Mars
These settlements could use the Martian moons Phobos and Deimos for bases and for materials, and explorie the surface with sterilized tele-operated avatars.