2008 Annual Science Report
NASA Ames Research Center Reporting | JUL 2007 – JUN 2008
The possibility of life traveling from Earth to beyond, and, in general, life traveling from planet to planet, has captured the public’s imagination for a century or more. We are now poised to assess this possibility with experimentation. In this project, we focus on halophiles — organisms that live in high salt environments — as potential Earth life to survive space travel. Thus we have explored high UV and high salt environments, and have flown some of these organisms on European space missions. This year we also began to develop the use of high altitude ballooning to mimic travel beyond the surface of the earth.
We examined the survival in space of both Synechococcus (NŠgeli), a halophilic cyanobacterium isolated from the evaporitic gypsum-halite crusts that form along the marine intertidal, and also Halorubrum chaoviatoris a member of the Halobacteriacea isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond. We employed the Biopan facility flown in Earth orbit to demonstrate that, when exposed to the space environment for two weeks, Synechococcus (NŠgeli) and Halorubrum chaoviatoris exhibited higher survival rates than all other test organisms except Bacillus spores (Mancinelli, et al., 1994). These results led to a proposal (Rothschild, PI) submitted in response to an Announcement of Opportunity for Externally Mounted Payloads (SP-1201), to extend and refine these experiments. The proposal was selected and is part of the experimental package for the external platform space exposure facility on ISS. The experiment is on the flight manifest for December 2008. Results of this study are relevant to understanding the evolution of life on early Earth, the future of life beyond Earth, the potential for interplanetary transfer of viable microbes via meteorites and dust particles as well as spacecraft, and the physiology of halophiles. In preparation for this upcoming flight several ground simulation experiments were conducted. During the last year two sets of experiment verification tests were conducted and are ongoing at the DLR in Cologne Germany. The first set of tests was to determine bio-compatibility with the final flight hardware and its configuration. Our organisms were placed in the hardware and exposed to a simulated space experiment for one month. At the end of the month the organisms were tested for viability. The results indicated that the flight hardware (including adhesives) were not detrimental to our organisms. The second set of experiments tested the compatibility of the different types of samples (e.g., archeal and bacterial halophiles, Bacillus spores, cryptoendoliths, and various plant seeds) with each other.
Two field trips were conducted to Cargill Salt Company, San Francisco Bay. In both cases, samples were collected for potential collaborations on the viruses on hypersaline environments.
Several high altitude balloon launches were conducted. On March 8, 2008, BioLaunch B08A was a high-altitude balloon flown to a height of 106,6534 ft (32,508 m), on a clear day out of Galt, California. One component of the experiment was to send a radiation badge on top of the payload, exposed for the duration of the flight. B08A was launched at 8:39 AM, PST, and recovered at 11:52 AM, PST, so the total time of exposure for the radiation badge was 3:13 hours. Knowledge of how much radiation is present in the atmosphere is at present, not well documented. This knowledge is crucial for analysis of life in the upper atmosphere. Using X-9 dosimeters, it was determined that the total amount of radiation received over the duration was 0.9 mRem, well above the ground controls. This data was analyzed by Landauer, Inc. 0.9 mRem over 3:13 is equivalent to 6.715 mRem in a day or 2452.663 mRem over a year. According to a study done at Emory, natural environmental radiation is around 300 mRem/year, which has a negligible health risk. In addition, an exposure of 10,000 mRem is thought to increase the risk of cancer over a lifetime by 1%. According to the Space and Life Sciences Directorate Flight Readiness Review for STS-104/7A , the acceptable Daily Average Exposure for astronauts was 29 mRem/day. It is important to note that this mission was at a considerably higher altitude than B08A. It has been shown in previous flights that environmental radiation at altitude has a considerable effect on bacteria as compared to ground controls.
PROJECT INVESTIGATORS:Rocco Mancinelli
PROJECT MEMBERS:Gerda Horneck
RELATED OBJECTIVES:Objective 5.3
Biochemical adaptation to extreme environments
Adaptation and evolution of life beyond Earth