From: henry@zoo.toronto.edu (Henry Spencer)
Newsgroups: sci.space.science
Subject: lunar bacteria (was Re: MOONBASES)
Date: Mon, 17 Apr 1995 14:23:53 GMT
In article <3mjmn6$7cg@newsbf02.news.aol.com> lklaes@aol.com (LKlaes)
writes:
>It is now seriously in question whether any microorganisms carried to
>Luna in 1967 aboard the unmanned Surveyor 3 lander actually either
>existed or survived when brought back to Earth by Apollo 12 in 1969.
>It is believed that the microbe found in the lander's camera had
>actually appeared when the camera was exposed momentarily in
>nonsterile conditions.
Is there a reference for this?
Quite recently, more or less by chance, I ran across an old NASA report:
"Analysis of Surveyor 3 material and photographs returned by Apollo 12".
It's a substantial book, published in 1972. (It did not have an SP-xxx
etc. publication number that I could find.) I only glanced at most of it,
but read the biology report.
The bottom line is that the folks who did the work made quite a
convincing case that the bacteria really had survived the trip to the
Moon and back.
They got positive results from one and only one location in the camera:
the most inaccessible one. The positive result came from insulating
foam sandwiched between two circuit boards, reachable only through small
holes in the boards after considerable disassembly. All the more
accessible areas, where contamination would have been expected to appear
more strongly, were totally sterile. The tools and culture media
likewise tested as sterile.
Furthermore, there was a substantial delay--several days--before growth
started. This is typical of bacteria recovering from severe
dehydration, and not what would be expected from contamination with
fresh bacteria.
They noted that the Surveyors were not sterilized -- although some
attempt was made to minimize their bacterial load -- and that thermal
models put the maximum temperature in that foam on the lunar surface at
about 70degC. Given this, they commented that the survival of a few
organisms (they estimated the bacterial content of their foam sample at
under 50) was not really a great surprise. Night-time cold and extreme
dehydration were the only really severe environmental stresses
involved, and bacteria are noted for their ability to survive these.
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