August 1, 2011.
For the Mars Sample Return project, we have evaluated potential materials that can be used for sample container hardware which will maintain material integrity on Mars for a long period of time and will not introduce terrestrial contaminant to the samples. In particular, we have evaluated the advantages and disadvantages of using Teflon or high-Nickel alloys for the sample container. In a distinctly different activity, titled Evaluation of a Rapid-Heating High Temperature Sterilization Test Apparatus we were interested to see the effects of atmospheric entry heating on microorganisms attached to spacecraft surfaces. By sufficient heating the spores may be inactivated by the heat generated as a spacecraft enters the Mars atmosphere. Knowledge about thermal resistance removes uncertainty and lowers the contamination risk. Results can later add to the understanding of burn-up and breakup modeling. An apparatus used in this project was built earlier this year for testing atmospheric entry heating profiles and now we are doing a more complete evaluation. The key feature of the apparatus is to provide a method to control the heat exposure and temperature profile that bacterial spores would experience. Preliminary results from spore inactivation testing reveal that it is possible to inactivate the spores at temperature as low as 175 C in as little as 15 seconds.
Yin Lin and Wayne Schubert
NASA Jet Propulsion Laboratory (JPL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation.