Subject: Aerospace Corporation Studies Focus On Spacecraft Sterilization (Forwarded)
Date: Fri, 03 Aug 2001 19:51:00 -0400
From: Andrew Yee <ayee@nova.astro.utoronto.ca>
Organization: Jet Propulsion Laboratory - Pasadena CA
Newsgroups: sci.space.news
Followup-To: sci.space.policy
Aerospace Corporation
El Segundo, California
7/30/01
Studies Focus On Spacecraft Sterilization
The Aerospace Corporation has landed a follow-on effort with NASA's Jet Propulsion Laboratory (JPL) to continue researching the effectiveness of spacecraft cleaning methods used by NASA in missions to planets and moons that could harbor life.
A second $50,000 task came to Aerospace as a result of successful research in the same area that was completed for JPL in October 2000.
"Sterilization of spacecraft is very important for NASA missions to planets and moons that could potentially harbor life," explained Dr. Carl Palko, a project engineer involved in the research.
"Outbound sterilization and cleaning is important to prevent both the accidental contamination or infection of alien worlds with terrestrial organisms and the accidental contamination of extraterrestrial soil or ice samples being returned to Earth with terrestrial organisms that could be mistaken as evidence for alien life," Palko said. The original effort focused on developing technologies to achieve sterilization through a cleaning process in which all organisms were removed. The work involved three areas: characterization of spacecraft materials, characterization of spacecraft cleaning methods, and experimental investigations into contaminated surfaces.
Hardy Spores
Palko said that one question JPL had was whether terrestrial bacteria might form igloo-like structures on aluminum surfaces when the surfaces dried. Many bacteria, he said, form spores that enable them to survive millions of years in poor conditions, such as extreme dryness or extreme cold.
"If the igloo-like structures on the inoculated aluminum really contain spores, it could seriously affect efforts to clean spacecraft to a level of sterility. The preliminary results of Aerospace and JPL experiments indicate that the domes may indeed contain spores, but further investigation is needed," he said.
The follow-on effort will continue research in this area and will combine the three task areas into a single investigation to measure the effectiveness of the cleaning method on selected spacecraft materials.
IMAGE CAPTIONS: [http://www.aero.org/news/current/sterilization.html]
[Image 1]
Suspected sporehouse cut with a focused ion beam milling system to the dimensions of 20
micrometers by 10 micrometers, or approximately one-fifth the width of a single human
hair. (Photo by Dr. Gary Stupian)
[Image 2]
Dr. Gary Stupian, seated, takes a photo of a suspected sporehouse using a focused ion beam
milling system while team members, from left, Dr. Brent Morgan, Dr. Carl Palko and Dr.
Russell Lipeles observe. Not pictured are team members Myriam Easton and Ken Luey. (Photo
by Eric Hamburg)
Subject: IS: Spacecraft Sterilizatin - WAS: Viking data re-examined.
Date: Mon, 30 Jul 2001 08:27:57 -0400
From: rk <stellare@nospamplease.erols.com>
Organization: sel
Newsgroups: sci.space.history
References: 1 , 2 , 3
OM wrote:
...Back in '85, I did a term paper that dealt with the same data conclusions. The circadian rhythms could have been the result of life processes following those patterns, but they could have been caused by external influences as well. The loophole here with Viking is that the data I dug up back then that dealt with how the lander was sterilized wasn't complete, and it wasn't clear just what the full range of steps taken actually was.
Is that the paper was not complete or the sterilization of the lander was not complete?
Interestingly, I just read a paper, to keep up to date, which dealt with parts sterilization.
Current Results of the Electronic Part Sterilization
Program at the Jet Propulsion Laboratory
J. Visser, JPL
1967 Annual Symposium on Reliability, January 10-12, 1967
Washington, D.C.
pp. 312-322Summary
This report documents some of the preliminary results of the electronic parts sterilization program at the Jet Propulsion Laboratory (JPL). The program is geared to reflect current NASA sterilization policy. The primary objective of the electronic part sterilization programs is to establish an approved list of sterilizable electronic parts. The major effect of the current JPL program is concerned with heat sterilization studies on representative part types from each major part category, specifically in relationship to the reliability of the devices.
Now, to take an excerpt from the paper:
The main scientific emphasis will be exobiology - research into the existence and origin as well as the evolution and nature of life beyond Earth. ... requires, first of all, that the particular spacecraft itself be thoroughly cleansed of all earthborn micro-organisms. ...
Parts for these tests were cycled, non-operating, from 145 degrees C for 36 hours to 25 degrees C for 24 hours, for up to six cycles. I have a paper on Surveyor somewhere, and I think they used slightly lower levels, can't quickly find it. Rats. Any one know what they did for the Viking program or any other programs or what today's standards are?
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