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[Fwd: contamination]



Apparently, the first copy I sent didn't reach the list, or is
backed-up. If it did get through, I apologize for the second copy.

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> Not really.  The biologists make sense, and the
> conclusion is commonly held.

The conclusion that Mars may hold life is commonly held. The possibility
that Mars life may pose a threat, however small, is also good sense. As
for canceling a Mars flight on that basis, that is not good sense. If
desired, we can even have reasonable safeguards on the Marsr hab. For
instance, chemical showers in the airlocks before and after an EVA.

The CDC biologists won't argue with this. They have the same
precautions. If they admit this is inadequate, they are also publicly
stating that their own safety precautions are suspect. These people work
with the most deadly diseases known to man, catching one is worse than
death. Their labs are near downtown Atlanta, a significant metropolitan
center. If one of these virii got out...  
  
>(Though I willingly concede
> NASA's Dante robot did leave a lot to be desired, there is really no
> need to go down canyons in order to get a pretty good answer to the
> question of whether anything is living on Mars.)

Betting against robots is not wise, cosidering the rate of technological
advancement. But humans still have the dexterity, and the _adaptiveness_
to carry out a mission better than any machines we have now or will have
in the foreseeable future. 

> Several (2-3) long range (100 kilometer) rovers, with 1 or possibly 2
> sample returns, should be enough to
> make a pretty good first assesment.  At current funding
> levels this should take about 10-20 years.

They will make a good surface assesment, but not for what you are
specifically looking for, life. Imagine letting Sojourner or any Mars
rover in the next 50 years loose in the Rocky Mountains. How long will
it take the rover to find a dinosaur fossil?


> Once again, do we really have sufficient evidence to assert that
> contamination of the Earth is unlikely?
No, but with reasonable precautions, we can bring the chances to very
nearly 0. (The chances of anything happening are never exactly 0)
 
Now, to Darryl's ill-informed statement, cut and pasted here:

>Hi All-

>Please.  As has been stated by the major-domo, this list is not the >venue
>for wildly speculative personal beliefs framed as facts...like the >recent
>fatuous proclamation posted earlier today:


>>Did you know that oxygen, ozone, and water would all
>> be poisonous to Martian life? 

>(REALLY?!  I didn't know that!)        


Darryl:

Ozone (03) is a corrosive gas. It can cause materials to be brittle,
your lungs to scar, and it is used in sterilization. Earth does not have
enought 03 to kill the microbes we have now, but considering the very
low levels on Mars, the Martians would not find life here easy.

Oxygen (O2) is also a poison in high quantities to Earth life. Because
it will attack other biological specimens in the same way it does to
Earth, even low levels should be lethal to Martian microbes. I state
this on two assumptions: 1) Mass extinctions were triggered on early
Earth by oxygen 2) Terrestrial life has evolved to need oxygen. Martian
life has not.

H2O: I am not sure exactly how poisonous this is, just that it is
supposedly toxic to us in certain situations. I will compare to hydrogen
peroxide (H2O2). You do know what that does, right? 


As for Darryl himself, we all know he is one to tell us how to act on
the list. :-)

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