Question of the Week Podcast

Question of the Week episode

Mon, 6th Aug 2012

Could we introduce life onto Mars?

Figure 2: The surface of Mars (c)  NASA

Figure 2: The surface of MarsThis week we speak with NASA’s Planetary Protection Officer to find out if we could, and should, introduce life onto Mars. Plus we ask is a human producing Vitamin D a bit like a photosynthesising plant?.....

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One of the big concerns is that we don't introduce unwanted life onto the planet until it is thoroughly studied.  Thus Martian probes are assembled to be more sterile than your average surgical suite.

There have been many questions about whether there are in fact methanogens on Mars which could be easily obscured by terrestrial life it was to be introduced.  If we were to find life on Mars, understanding the DNA/RNA/Protein/Amino Acid structure, and chirality of the life would be critical to understanding the origins of life here and across the universe.

However, any colonization of Mars might also require intentionally introducing terrestrial extremophile life to the planet.  A lack of surface water in the equatorial region could be a problem.  Perhaps there would be some extremophiles that could adapt to the advancing and retreating ice in the polar regions.  Low oxygen content in the air would be a limit for some life forms, but there are many anaerobic bacteria, as well as plants that require carbon dioxide which might be plentiful enough rather than oxygen. 

Subsurface organisms might live similar to what we find on earth subsurface. CliffordK, Sun, 15th Jul 2012

The question asked was "Could we introduce life on Mars in order to 'terraform' it?", to which I think the obvious answer is no.

Assuming this would be Earth life, it would have evolved to adapt perfectly to conditions already existing here, specifically on Earth. While the existence of living things on Earth has changed the face of the planet, they would have had to be able to thrive in the initial conditions, however even the most extreme of extremophiles would struggle to even survive on the Martian surface today.

'Terraforming' seems to me to be more an engineering problem, following which you might have conditions suitable for Earth life to take hold.

And then of course what would be the point? Unless there is a chance of humans being able to survive there in the future outside environmental domes would there be any? Guthers, Wed, 18th Jul 2012

Terraforming is still firmly in the realms of science fiction.
Some have suggested that we could do something on Earth to combat climate change of 1 or 2 degrees  - but the transport of materials to Mars is much more difficult, and the required temperature change of around 90C/150F is much more challenging.

One of the more exhaustive fictional attempts to sketch out such a programme was the "Red Mars" trilogy by by Kim Stanley Robinson,

The titles of the three books are three primary colours, representing 3 stages of an imagined project taking centuries:

Red Mars: A dry, airless desert, as it is today

Green Mars: Introducing Plants

Blue Mars: Melting an ocean and producing a breathable atmosphere

evan_au, Fri, 20th Jul 2012

We've already started the process.  In 1971, Mariner 9 was launched to orbit Mars.  Because it was an orbiter, NASA did not sterilise it - maybe they were hoping that a manned mission would be able to retrieve it before it contaminated Mars.

That isn't going to happen, and Mariner 9 is expected to deorbit sometime in 2022, starting the very slow process of introducing Terran life to Mars.  IF any organisms survive the crash, they could start to spread, helped by the Martian dust storms, and very gradually adapting to the more favourable environments that they encounter.

Any searches for Martian life after that will have to be designed to tell the difference between native organisms and introduced ones.

There's only 10 years left. abiqua, Sun, 22nd Jul 2012


Thanks for the note. 
Terrestrial life could certainly become an invasive species on Mars.  It is something that as a society we need to decide how to deal with it.  If we wish to colonize Mars, then some terrestrial life will undoubtedly escape.  Perhaps the first step would be to intentionally stimulate the growth of micro-organisms, bacteria, algae, fungi, and etc.  However, of all the planets, perhaps Mars is the second most likely to have evolved life of its own (after Earth).  So, it is still a prime planet for searching for "other life". CliffordK, Sun, 22nd Jul 2012

There is actually a book, referenced with research articles about the possibility of contamination of Mars (sorry for preview only).  It sounds like there is a high possibility that there has already been at least some Martian contamination from Earth, although the viability of some potential microbes might be limited.  Others might be protected if buried.  Growth of the microbes, and spread on a planetary scale would still be quite slow. CliffordK, Sun, 22nd Jul 2012

I believe there are enough extreme bacteria living here on earth, that either could survive, or could be changed to easily adapt to a martian environment, the problem is the time it would take any population's to "evolve" into higher life forms needed to complete the terra forming.  I would think some plants, and insects might be genetically altered to survive if not now, in a short time if serious effort is put into the effort.  But to completely terra form the whole planet in a short time is not possible considering our current technology.

I believe maybe before something like that is even thought of, we first think about the long time survivability of life on this planet, and start doing things to make sure this planet does not need "terra formed" in a 100 years or so because it's too contaminated to support life..... Emc2, Wed, 25th Jul 2012

It is quite possible that Mars would be incapable of supporting a terran atmosphere.  That doesn't mean that it it would be incapable of supporting life.  But, humans in our current form may not be able to walk outside without assistance.

I don't think we have any idea how to generate quadrillions of tons of atmospheric gases.  Some oxygen can be extracted from the rocks, but quadrillions of tons?  And, even if we could generate it, if the gasses are slowly lost into space, then it would be the worst kind of waste of non-renewable resources.  A krypton/xenon atmosphere might work which could at least supply pressure, but not necessarily breathable, however, it would be much more difficult to generate.

If the planet is, in fact, sterile, then one option would be to supply it with the basic forms of life, bacteria, algae, amoebas, worms & etc.  Then, sit back and wait a few billion years to see what develops.  But, it is quite possible that without a dense atmosphere, it would never develop larger, and more intelligent life forms.  Even with introducing water, it likely requires a dense oxygen atmosphere to maintain oxygenated water, and thus aquatic life.

Anyway, even if humans would have to live inside structures, it would be helpful if one could at least grow some of the food crops in the open atmosphere.  And, perhaps there would be fewer parasites.  CliffordK, Wed, 25th Jul 2012

There is no way any Earth organisms would be able to survive and live in Martian conditions, however modified. They are just too different. The main reason for not wanting to contaminate Mars, or anywhere else - they crashed the Galileo probe into Jupiter rather than risk accidental contamination of Europa, is to prevent false positive results if it looks as if some kind of indigenous life is found. Guthers, Mon, 30th Jul 2012

Yep, there is no way...AGREED  :)

NoraSmith, Tue, 31st Jul 2012

Space historians will recall that the journey to the stars has more than one life form on its passenger list: the names of a dozen Apollo astronauts who walked on the moon and one inadvertent stowaway, a common bacteria, Streptococcus mitis, the only known survivor of unprotected space travel. As Marshall astronomers and biologists met recently to discuss biological limits to life on Earth, the question of how an Earth bacteria could survive in a vacuum without nutrients, water and radiation protection was less speculative than might first be imagined. A little more than a month before the forthcoming millennium celebration, NASA will mark without fanfare the thirty year anniversary of documenting a microbe's first successful journey from Earth.

Three decades after Apollo 12, a remarkable colony of lunar survivors revisited Emc2, Thu, 9th Aug 2012

Ordinary Earth life can't survive on Mars but there are many lifeforms on Earth that have extraordinary "extremophile" capabilites and some of them could survive there just as they are right now. Some could even reproduce on Mars if they found just a small trace of melting salty brine there, maybe as thin films on the rocks, or even the sparse morning and evening dew you get at some lattitudes on Mars. The don't need oxygen and some indeed can manage fine just on salty brine and whatever minerals are in the rocks - so called "primary producers".

Then - if we do introduce life to Mars in order to terraform it, this might need to be in a carefully selected order. E.g. you might not want to introduce aerobes until Mars has a well established oxygen rich atmosphere already, because they might take too much oxygen out of the atmosphere all the time while you are trying to add it in. So - might need to take great care what you take to Mars in the early stages. This probably rules out any human visits to the surface for quite some time if we do want to terraform it eventually - though you could explore it by telepresence using rovers and even humanoid robots on the surface operated by telepresence from orbit.

If life is there and native to Mars chances are that public opinion and the final decision will be not to visit it at all for now. But not so much discussed - if there is no life there - still the pre-biotic chemistry and what we could learn from a pristine planet that got almost to the stage of evolving life but didn't quite make it - that also could be of immense value and you would want to keep it uncontaminated if you possibly can.

We have definitely brought Earth life to Mars already in small numbers with our spacecraft. And even Curiosity - it's computer isn't sterilized, just protected from Mars by filters to keep any micro-organisms within. Eventually over geological time those filters will fail. And other spacecraft, quite a few have crashed not so well sterilized as Curiosity by far, even Viking wasn't that thoroughly sterlized by modern standards. So - the question is not have we introduced Earth life to Mars - but can it be contained and is it biologically reversible - can we remove it again if we want to. There is some hope it might be simply because the surface of Mars is so hostile to most forms of Earth life. So - but if it was decided you have to keep the planet pristine or terraform in a carefully controlled sequence of micro-organisms - first you would need to remove all the existing sources of Earth life from Mars. Probably with better technology than we have today you need to go to Mars and remove every last trace of the rovers we sent their including the crashed ones and the debris and parachutes etc. and also the Mars soil they came into contact with as well as far as possible - and remove those all from Mars before you begin to make it hospitable for the photosynthesizing oxygen producing life for terraforming - or else to make sure it remains pristine - if we follow either of those future paths. Which would be extremely hard to do right now but with future technology - maybe it can be done.

BTW for more see robertinventor, Tue, 6th Nov 2012

I don't understand. Why is it so important that we don't contaminate Mars. I understand that if we contaminate Mars it will become almost impossible to study if life ever existed on Mars... But is it really that important? Is it important enough to stop all other scientific studies on Mars? Karl Parks, Sat, 23rd Feb 2013

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