Slashdot Mirror
Mars Exploration Must Consider Contamination
letxa2000 writes: "CNN is reporting that the National Research Council has submitted a report to NASA that recommends certain precautions be taken if NASA is to send astronauts to Mars to guarantee that they don't bring back Mars-based bacteria and contaminate earth; including possibly banning the return vehicle from entering the Earth's atmosphere. What is the likelihood of bacterial life on Mars infecting the earth if we ever get around to visiting Mars in person?"
Putting a scare of contamination into people is just a way of hyping the possibility of life on mars and the necessity of going there.
t
Shouldn't we be more worried about the other way around first - the contamination of Mars by some Earthly micro-organism?
A toxin might kill an astronaut. That would be tragic, but not a disaster. The problem to be worried about is communicable disease, namely an organism (bacteria, virus) that harms the host and can spread. The organisms that work this way on this planet have evolved with us over a very long period of time. An organism that had never encountered a human before, or perhaps even earthly DNA, seems exceedingly unlikely to be communicable -- hasn't had the practice.
Still, I have to admit, this sounds an awful lot like, "this code should work".
The fact of the matter is that preventing contamination is impossible - we have pieces of Mars rock entering our atmosphere all the time. Most bacteria is incredibly hardy - the vacuum of space and heat of re-entry are certainly survivable. Please see this essay, entitled "Estimated Flux of Rocks Bearing Viable Lifeforms Exchanged Between Earth and Mars". Realistically, our primary concern is with accidentally seeding Mars with Terran bacteria - if that happens, we may never know whether or not Mars had any native life.
sending people is more expensive but it gets you more funding as well.
Once we know one way or another what kind of life exists on mars, then we can start thinking about sending humans. But that will invariably and irrevocably change mars.
Goodness, let alone so-called Mars bacteria. Let's think about this - if Mars has bacteria on it at all, shouldn't it have evolved at roughly the same rate as Earth's?
You cannot compare. Since Martian bacteria would face different evolutionary preassures. On Mars surviving extremes to temperature is more important than on Earth. On Earth surviving in an oxygen rich environment is important, as is competition with all sorts of other organisms. (Including many which have sophisticated methods of killing bacteria.)
All right, Mr. Submitter, I'll answer your question: I haven't the foggiest idea. I've learned a little here or there about microorganisms and their possible existence outside of the Earth during my lifetime, and I regard myself as a relatively intelligent person, and tend to have strong opinions about most anything, including stuff I don't know much about. But the awful truth is that I'm not the least bit qualified to speculate on the likelihood of extraterrestrial infections on Earth. That's not an informative answer, I admit, but it's honest, and I daresay a great deal more honest than nearly all of the responses you've received so far.
To be sure, there have been a few replies so far that seem to be thoughtful and well-informed, and perhaps they come from people who really are qualified to answer the question; but like I said, I'm not really qualified to make that evaluation. Almost all of the rest, it seems to me, are comments from people who may be relatively intelligent, may have read a thing or two about the possibility of extraterrestrial life, and have all kinds of strong opinions about anything, and now they are speculating with wild abandon. Which is fun, but they will give you almost no reliable answers to your question, and may lead you completely astray.
You probably wouldn't be having this problem if you had posted this question in a forum about "News for Molecular Biologists, Stuff That Matters to Astrophysicists". Why did you expect you expect to get any useful answers here?
Always keep a sapphire in your mind
Shouldn't they also be concerned about bacteria from earth contaminating Mars? I sure hope they have been. It would be a shame if we sent someone up there only to discover that Mars was crawling with life, but that the life rode to Mars on one of the earlier probes.