National Academies Press: OpenBook

Preventing the Forward Contamination of Mars (2006)

Chapter: Appendix D History of Recommended Values for Probability of Growth

« Previous: Appendix C Summary of Procedures Currently Used to Assess Bioburden in Spacecraft Assembly Clean Rooms and on Spacecraft
Suggested Citation:"Appendix D History of Recommended Values for Probability of Growth." National Research Council. 2006. Preventing the Forward Contamination of Mars. Washington, DC: The National Academies Press. doi: 10.17226/11381.
×

D
History of Recommended Values for Probability of Growth

Historically, the approach used to evaluate planetary protection requirements for spacecraft sent to Mars depended on efforts to estimate the probability Pg that Earth microorganisms would grow in the martian environment (see Chapter 2). As shown in Figure D.1, estimates of Pg varied by ten orders of magnitude during the period from 1964 to 1978. As the committee discusses in Chapter 5, the scientific basis for estimates of Pg—knowledge about the capability of Earth microorganisms to survive and propagate on Mars—remains strongly limited.

FIGURE D.1 Estimates of the probability of growth (Pg) of Earth microorganisms on the planet Mars. SOURCE: H.P. Klein. 1992. History of Pg. Pp. 41-52 in Planetary Protection Issues for the MESUR Mission: Probability of Growth (Pg), H.P. Klein, ed. NASA CP 3167. NASA, Washington, D.C.

Suggested Citation:"Appendix D History of Recommended Values for Probability of Growth." National Research Council. 2006. Preventing the Forward Contamination of Mars. Washington, DC: The National Academies Press. doi: 10.17226/11381.
×
Page 140
Next: Appendix E Approaches to Bioburden Reduction for Lander Missions to Mars »
Preventing the Forward Contamination of Mars Get This Book
×
Buy Paperback | $45.00 Buy Ebook | $35.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Recent spacecraft and robotic probes to Mars have yielded data that are changing our understanding significantly about the possibility of existing or past life on that planet. Coupled with advances in biology and life-detection techniques, these developments place increasing importance on the need to protect Mars from contamination by Earth-borne organisms. To help with this effort, NASA requested that the NRC examine existing planetary protection measures for Mars and recommend changes and further research to improve such measures. This report discusses policies, requirements, and techniques to protect Mars from organisms originating on Earth that could interfere with scientific investigations. It provides recommendations on cleanliness and biological burden levels of Mars-bound spacecraft, methods to reach those levels, and research to reduce uncertainties in preventing forward contamination of Mars.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!