A document summarizes a study in which it was found that spores of the SAFR-032 strain of Bacillus pumilus can survive doses of ultraviolet (UV) radiation, γ radiation, and hydrogen peroxide in proportions much greater than those of other bacteria. The study was part of a continuing effort to understand the survivability of bacteria under harsh conditions and develop means of sterilizing spacecraft to prevent biocontamination of Mars that could interfere with the search for life there.

A major conclusion stated in the document is that standard UV treatments that are effective against spores of other bacteria may not be sufficient to inactivate spores of SAFR-032 and, hence, may not be sufficient to inactivate all bacterial spores. Noting that heretofore, spores of B. subtilis have been used as a biodosimetry model for the UV inactivation of spores, the document presents the further conclusion that B. subtilis should now be considered unreliable as such a model. It is further suggested that because of its greater resistance to sterilization processes, SAFR- 032 should be substituted for other biological indicators that have been used in hospitals and government facilities as indicators for quality control of sterilization.

This work was done by Kasthuri Venkateswaran, David Newcombe, Myron T. La Duc, and Shariff R. Osman of Caltech for NASA’s Jet Propulsion Laboratory.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Innovative Technology Assets Management


Mail Stop 202-233

4800 Oak Grove Drive

Pasadena, CA 91109-8099

(818) 354-2240

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Refer to NPO-40953, volume and number of this NASA Tech Briefs issue, and the page number.

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.