Mars Sample Return - Threat of back-contamination

AndyM · 2002-04-04 09:06:13

I recently came across the International Committee Against Mars Sample Return (www.icamsr.org). Prior to this, the only arguments that I heard in the debate about the threat of back contamination came from Zubrin. His arguments that the threat is highly exaggerated seems reasonable to me but it is interesting that there are many scientists of notable repute (including biologists) that disagree with him. I still support a MSR primarily because of the technologies it will demonstrate with respect to a manned mission, though I don't think it is necessary to launch a MSR prior to a manned mission. Anyone with arguments for or against the threat of back contamination?

Interesting articles by Zubrin and others on this topic can be found at www.planetary.org.

As an aside, I read an article that claimed that bacteria from the earth were inadvertantly present on the Survejor 3 spacecraft which landed on the moon in 1967. Parts of Survejor 3 were retrieved by the Apollo 12 crew in 1969 and when the parts were examined on earth, a colony of bacteria was found that had apparently survived the two and a half year stay on the moon.

Adrian · 2002-04-04 11:18:34

Following links from ICAMSR, I found this excellent article on the subject by Barry E. DiGregorio, entitled The Dilemma of Mars Sample Return.

Not so impressive are the scare tactics used by the ICAMSR homepage, which outline how a number of microbes can wipe out entire populations. The ridiculousness of this argument is clear - we're talking about returning samples from Mars, not from Earth. Even if there are viruses and bacteria in this sample (as the ICAMSR postulates), they will have evolved in an environment so incredibly different to that of Earth that they will have effectively zero chance of infecting humans. We don't expect extremophiles that exist in subzero temperatures to proliferate in the human body, and indeed none do.

Arguments against sample return also make heavy use of the BSE crisis that struck Britain, in which a prominent scientist claimed that there was no chance of BSE being transmitted from cows to humans. Well, it did, via a prion. However, what does this tell us? That we shouldn't trust what people say? That we should be more careful?

Of course we should be more careful, when dealing with a known infectious and fatal disease that exists in bovines and already exhibits evidence of being able to travel from a cow (a mammal) to a human (another mammal). But samples from Mars are a qualitatively different concern.

I don't doubt that we should take appropriate precautions when doing sample return - we should have a purpose built, maximum security research lab on Earth to study the samples, we shouldn't engage in passive-Earth capture (where the probe simply zooms straight into our atmosphere). But I wonder whether the opponents of sample return will be satisfied by anything - I get the feeling that they would be happiest keeping the microbes off Earth completely. And so - would they ever let Martian astronauts return to Earth?

AndyM · 2002-04-04 13:14:45

There are links to several interesting articles. But there is one thing that I haven't been able to find. One of Zubrin's arguments is that the earth is continuously bombarded by martian meteorites and that there is a high probability that microbes could survive a trip aboard such a meteorite from mars to earth. Hence, if there are microbes on mars then we have almost certainly been exposed to them already. What are the counter-arguments to this point of view?

Interestingly, the current systems architecture of the MSR mission calls for a passive-earth capture. It has even been described as using the earth as a catcher's mit.

Adrian · 2002-04-04 13:41:19

It's quite a nice argument by Zubrin, but along with its positive points it has its flaws. Yes, there probably are not insignificant numbers of meteorites from Mars hitting Earth, and in fact from analysis of Martian meteorites it's been found that they don't get baked when entering our atmosphere - their interior stays at quite a nice temperature (for the microbes, if there were any).

But there are a few problems. How long would a Mars meteorite be in transit for? Conservatively (and uninformedly), I would say at least a hundred years and probably a lot more than that - perhaps tens of thousands or millions. During that period, even toughened bacterial spores would have a hard time surviving. Also, there is the trauma that the microbe-bearing meteorites would undergo as they get ejected from Mars.

The simple fact is that any sample return mission will bring back Martian rocks in pristine condition, far quicker and more gentle than any Mars meteorite. I still think that there is a nonzero possibility of Mars microbes surviving a journey from Mars to Earth, but it's not as simple as Zubrin might make it out to be. We just don't know enough about the numbers or the conditions of meteorites that arrive from Mars.

Shaun Barrett · 2002-04-04 19:11:47

I don't like to sound repetitive about this but I think there's little danger of massive annihilation of Earth-based species by ravening hordes of Martian bacteria (or whatever)!
At the risk of boring you all to distraction, I have to say again that the evidence is almost overwhelming that impact cross-contamination between Earth and Mars has happened countless times. Bacteria are extraordinarily tough creatures; its difficult to eliminate them from anywhere even if you try your level best and use the best bactericidal chemicals devised by man. They're everywhere! The biomass of rock-dwelling bacteria in Earth's crust, it has recently been suggested, may outweigh the mass of the surface biota!
The Mars meteorite ALH84001 that caused a stir with its purported evidence of Martian microbes, was deduced to have been in interplanetary space for some 16 million years. This is no impediment to bacterial survival. The interior of the rock never became warmer than 40 deg.C (even during its fiery descent through Earth's atmosphere) and would have been shielded against excessive radiation. Microbial spores many millions of years old have been dug up here on Earth and found viable; some allegedly buried in salt deposits 250 million years old!
The inescapable conclusion from all this is that Earth-life and Mars-life will be found to be essentially the same; based on DNA/RNA and the same amino acids. Certainly there will be novel species to study because of long periods of isolation, but we are as much at risk of a pandemic every time we pull up a drill-bit covered in bacteria from 3 kilometres down in the crust of our own planet as we are in studying a rock brought back from Mars!
I am so certain of this in my own mind that I would be perfectly happy to handle Mars rocks unprotected. The crews on drilling rigs effectively do the same thing all the time.

Canth · 2002-05-02 14:51:43

I totally agree. I think the most important source of contamination we have to worry about on such missions is earth microbes getting to mars or into our sample. Earth bacteria (if they somehow survived) could compete with martian life some looooooooooong way down the road and hurt the natural enviornment. That seems about as likely as the earth being contaminated by martian microbes. The biggest reason to carefully handle a sample return mission is to prevent our samples getting contaminated by earth microbes. Contamination would greatly reduce the sample' s scientific value.

GOM · 2002-05-03 01:39:03

NRC warns against contact with possible Martian life forms.

http://space.com/missionlaunches/ap_mars_020501.html

The National Research Council (NRC) is recommending that safety take precedence and that missions to the Red Planet try to avoid encountering any possible life forms there.

"While the threat to Earth's ecosystem from the release of Martian biological agents is very low, the risk of harmful effects is not zero and cannot be ignored," the council said in a report released Wednesday.

The NRC urged NASA to establish "zones of minimal biological risk" by sending automated probes to test for organic chemicals or other life forms.

Astronauts could then be sent to areas with the lowest possible risk of encountering life that might either pose a threat to them or to Earth if it returned with them.

And in an additional step to avoid bringing back contamination, the study said, the returning spacecraft might have to be abandoned in space with the astronauts transferred to another vehicle to get back to Earth.

Shaun Barrett · 2002-05-08 03:10:07

At one point, in the late 1950s and early 1960s, before the Surveyor craft and well before Apollo 11, all sorts of terrible things awaited space explorers, and particularly Moon explorers.
Some "experts" theorised that any human who left Earth's atmosphere would suffer psychologically from a separation syndrome and descend into madness. When it didn't happen, they took the theory to the next stage and predicted that, although Earth orbit was OK because the astronauts were close to home, astronauts out in the void between Earth and the Moon would certainly be gripped by an unbearable melancholy at the sight of their home world so far away and become slavering morons! Some even predicted that, since no Earth creature had ever been out of Earth's magnetic field, its absence would probably be fatal. Again, of course, it didn't happen.
Next were the "biological experts" who contemplated lunar bacteria adapted to unspeakably hostile conditions on the Moon. Naturally, as soon as these bugs found a warm, wet human body full of nutrients, they'd think all their Christmases had come at once and promptly devour it; right there in the Lunar Excursion Module!!
That's assuming the LEM hadn't sunk half a kilometre into the fine lunar dust which some "experts" had predicted would cover large areas of the Moon, like a kind of super-quicksand.
Yet again, of course, nothing of the kind occurred in reality. And the lunar dust itself turned out to be non-toxic, too, despite grim predictions to the contrary!
They say history repeats itself, but .... so soon!! We're getting all the same sort of hysteria now about Mars and it's just too familiar! Half of the concern about highly reactive surface chemicals comes from the "fact" that the Gas Chromatograph Mass Spectrometers (GCMS) carried by the Viking craft failed to detect any organic compounds in the Martian soil. Gilbert Levin, who designed the Labelled Release Experiments on the same missions, has shown convincingly that the GCMSs were inadequate for the job and were quite capable of missing literally thousands of fully-fledged bacteria per gram of soil!! There is, therefore, simply no hard evidence for any nasty chemicals in the Martian regolith and yet the bad data have become accepted wisdom at NASA.
Send me to Mars! I'm not afraid. As I've said elsewhere in New Mars, I have a well-developed bull**** detector and I can hear it very clearly right now. We've lost our nerve; that's the real problem. We're like kids on school camp around the campfire after dark, telling each other ghost stories and scaring the **** out of ourselves!
Mars is just a planet; not some 'dungeons and dragons' horror-zone. It's high time we stopped wearing amulets and burning witches and simply got on with what we really do very well .... EXPLORING!!!!
Come on ... please ... while we're still young!
???

Mark S · 2002-05-08 09:29:36

It is imperative that the scientific community try to retrieve samples from Mars as soon as possible. Even if the tests for life come up negative, the mission will pave the way for humans to Mars.

The only problem with MSR is that none of the space agencies are committed to launching the mission. MSR is no longer a NASA priority, and I doubt that NASDA or ESA will launch the mission before 2014.

What can we do to make MSR happen? I know this is very optimistic, but I think that the Mars Society should raise the money for it and conduct the mission for themselves. If Translife is a success, this scenario will be a definite possibility. MSR will be expensve, but only the Mars Society believes in using in-situ propellant production for MSR, and it will be essential to test this technology on Mars before attempting a humans-to-Mars mission.

Omer Joel · 2002-05-08 10:29:48

The Martian soil is pretty antiseptic and highly-oxidant by itself; The chances of anything staying alive, let alone being biologically-active on the Martian soil or anywhere near the surface, with the oxidant soil, total lack of liquid water, extreme radiation levels, extremely low atmospheric pressure and extremely low temperatures, are so low that the risk from early Mars sample return mission and even early manned missions is extremely low. IMHO, if there is anything alive on Mars, it's probably in the Cryosphere, frozen deep under the surface since the times when Mars was far warmer. This would pose a threat to anyone only if deep-drilling equipment would be employed or if Mars will be terraformed.

Also, aren't the safety measures employed in the case of the Apollo 11 crew enough to prevent contamination from a Martian sample? At the worst case the international space station could be used as a quarantine zone for the samples to be tested in without risking contamination to Earth itself.

Mark S · 2002-05-09 17:12:15

In NASA's current MSR scheme, the sample container is left in LEO to be retrieved by a shuttle. The shuttle will then land at an isolated site like White Sands so the samples can be studied. The plan sounds okay to me from a safety standpoint (its far better than cooking the samples, like some have suggested.) It also avoids the contamination of the samples that may occur if the canister makes a landing by itself at land or at sea.

Still, it's unlikely that living organisms will be in the Martian soil. The best place for life to exist would be subsurface water. According to Mars Odyssey, the planet has plenty of it. I can imagine that Mars has an ecosystem similar to that found near the undersea vents on earth.

Shaun Barrett · 2002-05-10 02:54:36

"It is imperative that the scientific community try to retrieve samples from Mars as soon as possible. Even if the tests for life come up negative, the mission will pave the way for humans to Mars", states Mark S.
Actually, Mark S, from what I can make out, there are quite a few people out there who might not see it the same way you do! It seems that if the tests for life come up POSITIVE, that will be the red light for many and a powerful lobby against human exploration will swing into action to block any manned missions! (The inalienable rights of bacteria, and all that! ) I wouldn't put it past those same people, if the tests for life come up negative, to again lobby against humans to Mars on the grounds that it's just a sterile rock, very boring, and we should spend the money on social security.
But that's by the by. I still maintain that a MSR mission is going to be used by the budget boys, if not most of congress, as a convenient excuse to push a manned mission into the last half of the 21st century. I also maintain that such a tricky mission is almost certainly unnecessary when a small robotic laboratory can do all that's needed to evaluate the regolith right there on the Martian surface; and for a fraction of the cost.
Moving on: Omer Joel states that: "The Martian soil is pretty antiseptic and highly-oxidant by itself". I know this is the accepted wisdom which has been handed down by NASA ever since Viking. But, as I have tried to point out, the hypothesis of peroxides or superoxides in the Martian regolith is NOT proven. In fact, it is vigorously contested by no less a man than Gilbert Levin, the designer of the Labelled Release Experiments which also flew on Viking.
The only reason for the "toxic, highly-oxidising Martian regolith hypothesis", was the failure of the Gas Chromatograph Mass Spectrometers on the Viking craft to detect any carbon compounds (down to parts per billion levels). Since then, the same instruments have been used on Antarctic soils with the same results .... even though those soils actually contain THOUSANDS OF LIVING BACTERIA PER GRAM!!! The fact of the matter from all this, seems to be not that there is anything exotically lethal about Martian regolith, but that the GCMSs were inadequate for the task. In fact, despite repeated attempts by chemists in the decades since Viking, nobody has been able to create any combination of peroxides or superoxides which reproduce the activity of the actual Martian material tested on Mars by the Viking landers. From this, Dr. Levin has concluded that his LR experimental results actually did record the gas exchange activity of living organisms in the Martian soil. And guess what? ..... I think he's probably right!!
As I've stated and stated ad nauseum, I also believe that if those microbes really are there, they will be found to be pretty much like Earth microbes in all the ways that matter. The reason being that impacts on Earth and Mars have almost certainly cross-contaminated the two planets countless times since their creation. And besides, we've contaminated Mars many times with our bacteria and moulds ever since the Soviets started crash-landing unsterilised probes there in the 1960s.
Why does nobody listen to the sound and well-reasoned arguments of Dr. Levin? What is it about NASA that even when the premises upon which they base their arguments are called into very serious doubt, the arguments are nevertheless accepted as holy writ?! It's time we abandoned hypotheses that just don't add up. It's time to think; to re-evaluate; to come to new conclusions. Let's try using our brains and not chanting tired and unsustainable mantras!
Whaddyasay? Anybody agree?!

Omer Joel · 2002-05-10 03:42:36

Shaun Barrett, thank you for pointing out that the theory about the Martian soin being highly oxidant is not proven do far. Yet, I find it difficult to believe that anything lives on the martian surface, atleast not in the upper layers of regolith; even if the soil is not oxidant, Martian surface conditions are far from anything comfortable for life: extremely high radiation levels, extremely low temperatures and nearly no atmospheric pressure. If anything lives on Mars, it lives IN mars: either frozen in the permafrost/cryosphere (which term is correct?) from times when Mars was more hospitable, or living in hot water somewhere very deep under the surface where the heat allows liquid water to exist. And this might be the strongest argument against terraformation or even long term colonization: in drilling into the permafrost in order to gain water (or in heating Mars in a way which might someday cause the permafrost to melt), aren't we risking whatever life that might exist there? (or worse, aren't we risking contamination by whatever lives there?). This is why we need to get conclusive evidence regarding the exsitance of life on Mars before going there (hopefully, there will be no life there; otherwise we might have "moral" problems with the colonization project).

Shaun Barrett · 2002-05-10 07:08:00

Thank you, Omer Joel, for your reasoned response to my sometimes heated diatribes! I admit I do sometimes become impatient and a little hot under the collar but, then, if a man never becomes passionate about anything, is he truly alive?!
You are absolutely correct in saying that the surface conditions on Mars are ferocious and your argument that no organisms could be expected to survive them is a compelling one. However, in view of the extraordinary hardiness of terrestrial bacteria, it is my opinion (for what it's worth) that we may well find ourselves surprised by the extent of the Martian biota, if there is one! Though, of course, we'll never be certain until that automated laboratory's microscope sends us the first pictures of microbes in the soil. When and if that happens, you know what I expect we''ll see .... the same old familiar bugs we find here in our own backyards, but with some environmental adaptations.
And the beauty of doing the research remotely, on Mars not Earth, is that we have no risk of the contamination of Earth which seems to scare so many people and we won't even have to build a receiving laboratory (in orbit or otherwise). Thus we save time (many many years of it judging by NASA's drawn out schedule) and we save hundreds of millions of dollars.
Speaking of buried microbes, we have discovered bacteria here on Earth which we had to drill 3 kilometres underground to find. We have also found viable spores of bacteria purportedly 250 million years old buried in salt deposits. The human race has never encountered bacteria like these before since we have been separated from them by either miles of rock or vast expanses of time. In a sense, they are alien organisms; at least as much and probably more so, in my view, than any we will find on Mars because the surface biotas of the two planets have been mixed by impact transfer more often and more recently. Yet we don't build receiving laboratories with state-of-the-art quarantine facilities in order to study these microbes, which might just as easily turn out to be pathogenic as anything from Mars. ..... Doesn't that seem odd?
Tell me why I'm wrong, but I think we're taking the prospect of "Martian Malaria" very much too seriously!

RobS · 2002-05-11 22:54:23

The difficulties with contamination are two, I think: (1) even if the danger of contaminating the Earth with dangerous lifeforms is a billion to one, NASA cannot ignore it; the US government would be liable; (2) fear, an emotion one can never underestimate and can destroy even logical plans.

-- RobS

Mark S · 2002-05-13 10:19:14

I think that MSR is very important, but not from the standpoint that it will prove or disprove the existence of life on Mars. MSR will act as a testbed for the technologies that will allow HUMANS to determine whether life existed on Mars. Propellant production, ion propulsion, and direct re-entry, among other technologies, can all be attempted on a smaller scale in a realistic deep-space and Martian environment before they are used for a humans-to-Mars mission. As Zubrin said in "Case For Mars," MSR is like dropping two small robots in the Arctic and searching for fossils. The sampling you receive will not necessarily be representative of what Mars' regolith is like. Even a repeat of the Viking landers using better instruments would not have the range or the intuition available to human geologists and paleontologists.

alokmohan · 2003-10-11 05:23:01

Robot is no substitute fo human observation and thought.

Enyo · 2003-10-21 04:04:01

An important document when talking about this is:

A Draft Test Protocol for Detecting Possible Biohazards

in Martian Samples Returned to Earth (NASA/CP 2002-211842)

Sample return

http://spacescience.nasa.gov/admin/pubs … ples/index

alokmohan · 2003-10-27 05:10:41

NASA has a planet protection officer having no work.He concocts all sort of remote possibilities.

dicktice · 2003-10-28 17:59:08

Regarding Mars Sample Return: I can't believe all of you who are "for it" (and who seem so knowledgable otherwise) would endorse such a gamble, while the rest of the inhabitants of the one-and-only Home Planet know nothing of your Murphy's Law prone ambitions. Of course, once we become spacefaring, knowledge will dictate. But in our present state of ignorance, it's like brats in a sandbox before they've learned to walk--too impatient to wait before grabbing something outside the box to play with, that might possibly turn out to be cat-turds, and mess up the whole darn sandbox.
As an aside: Of what possible use could anything be, less than hundreds of well dispersed deep-core samples, from which to form valid planet-wide conclusions about the regolith of Mars? The present situation, with all this super-fine Mars surface imagery. simply screams for human exploration--not a seemingly endless series of Mickey Mouse "rovers" with toy shovels and buckets to scratch away at the surface!

Enyo · 2003-11-15 03:19:54

Yes and you're the brat that doesn't want to leave the sand box when mom calls.

I can guarantee you that you don't learn to walk by always crawling!

Another important site to look over is Cospar

I'm Enyo! I rule Murphy and his law!

Mad Grad Student · 2003-11-15 14:15:45

The way I see it, if the MSR mission digs up some rock from a few meters down in the surface, preferably near an aquifer, and doesn't expose it to the atmosphere for too long, it will almost definately return some sort of bacteria to Earth. This is not a bad thing at all, just think about how many thousands of micro- and astrobiologists from around the world will be clamoring to get a hold of some life that came to being completely seperate from Earth. And if we keep the samples sealed airtight (literally and metaphorically, with lots of security), there is no cause for alarm about contamination. Unless, of course, the microbes get out.

Very soon after the samples return, the demand for Martain microbes might become so great that NASA will attempt to culture them and sell them to labs around the world. If just one of these cultures being transported has even the tiniest imperfection in containment, thousands of spores and live bacteria will spread, in this world where it's possible to get anywhere within 18 hours of right now, around the globe very quickly.

As the laws of natural selection predict, the species that grows up in the harshest conditions will be the most successful. Being from Mars, I see two possible scinerios.

Scinerio 1: The bacteria are obligate anerobes, and die within minutes if exposed to oxygen. On Mars this would be no problem, they live underground on a planet with practically no oxygen at all, but on Earth they have a very difficult time and are forced to reside deep underground, incapible of human harm assuming they live long enough to even get there.

Scinerio 2: The bacteria are so well adapted to the harsh Martian conditions they are capible of weathering anything, high oxygen saturation, zero oxygen environment, extreme cold and radiation. On Earth they are wildly succesful, filling niche environments near the poles, in the upper atmosphere, there's even a strain that adapts itself to live in the human digestive system! Soon they become an intergral part of the Terran ecosytem.

Now, the only way I'm aware of that bacteria harm their hosts is by producing waste products that are toxic. The microbes really don't want to kill their host, as they'll probably die with it. We have no reason to assume that just because these bacteria are from Mars they will produce toxins specificallly capible of killing all forms of mamalian life. In fact, we really would only have to study the microbes in a contained environment for about a week or so to examine their waste products and see weither or not we have a doomsday scinerio at hand.

I'm all for the MSR mission, and don't like the way that bacteria and viruses are often protrayed as our enimies. Of all of the spices we know of, only an extremely small percentage of microbes are capible of causing more harm to humans than BO. Besides, if we do ever get a problem with extraterrestrial germs, perhaps our's would fight back, War of the Worlds style.

Not that it would happen, but wouldn't that be intersting?

Wim · 2003-11-16 04:51:49

I agree with the fact that it doesn't always have to be bad. I mean, how many movies for instance have the *good alien* (alias E.T.) in them ? I can think of E.T. (did I mention that before ?) but otherwise it is nowhere near good.
Mars Attacks, Independence Day, Alien(s), ... to name a few

Life on Mars will be found ! (in microsize, not cowsize fcours)

Shaun Barrett · 2003-11-19 05:32:49

Wim and Mad Grad Student:-
'Microbial life will (almost certainly) be found on Mars.'

Ditto!!!

jadeheart · 2003-11-19 16:58:55

In NASA's current MSR scheme, the sample container is left in LEO to be retrieved by a shuttle. The shuttle will then land at an isolated site like White Sands so the samples can be studied

i'm not exactly fluent in the intricacies of orbital mechanics & spacecraft rendezvous, but it seems to me we may be able to bring the samples back to ISS and finally get some bona fide use out of the thing. this would (er, could) isolate the samples from our biosphere and pacify the biological gloom-n-doom types, and the gov't gets to cover its ass, which is its raison d'etre anyway.

the question in my mind is whether the MSR will be an impediment to the advent of a humans-to-mars program. there's been some mention of MSR as a stepping stone for doing proof-of-concept stuff, but i can't help but wonder if it might wind up being a substitute for crewed exploration, or at least delay it past the end of my life. call me selfish, but i think we shouldn't lose sight of the grail-- human exploration. the microbes await us.

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Re: Mars Sample Return - Threat of back-contamination

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Re: Mars Sample Return - Threat of back-contamination

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Re: Mars Sample Return - Threat of back-contamination

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