return sample


From: sklug@primenet.com (sheri klug)
Subject: return sample
Date: Sat, 18 Oct 1997 21:45:44 -0600


Hi Stephanie,
Did you get an answer to your question about the prevention of possible
contamination from the return sample of rocks from Mars (2005 Mars mission)?
I had a chance to hear Dr. Ken Nealson speak at the Planetary Summer School
at Cal Tech last August on that very subject.  He had been part of a larger
community of scientists that had just finished drafting a document for NASA
on containment of possible contamination from extraterrestrial materials (I
think this document is available through NASA Headquarters).  In a nutshell,
Dr. Nealson (who is a microbiologist now working at the newly formed
exobiology group at JPL) said that a facility would be created, built and up
and running at least two years before the first return sample would land on
Earth.  It would indeed look very much like the CDC (Center for Disease
Control) and probably be located somewhere in the west, since the CDC is
already in the east.  Extraodinary care will be taken with the samples to
preclude any problems.  

An interesting discussion that came out of the Early Mars Conference held at
the Lunar/Planetary Institute last April concerning the definition of
"life".  There was a formal 2 hour debate with Dr. Dave McKay and his team
and a team led by Dr. Nealson concerning the validity of the claim of
possible evidence for life found in the ALH84001 meteorite.  The main issue
was the size of the structures seen (it was much smaller than the
nanobacteria we are used to here on Earth.)  Dr. Nealson gave a detailed
description (for the biologically challenged geologists at the meeting) of
how a earth-like cell is structured.  His main contention was that the size
of the bacterial structures was too small for the main "stuff" of a cell to
fit, once you had a cell wall, etc.  It was refreshing to hear the science
community that was at that meeting (approx. 170 people) ponder if a cell on
Mars had to be the same size...or if maybe the "stuff" like ribosomes, etc.
could be located on the outside, etc.  They were not limiting their thinking
to life here on Earth, but allowing for possible differences.  Anyway, I
hope this might have answered your question, that indeed, the science
community will be well prepared for the Martian rocks!