NSSDCA ID: 1975-083C-03
Mission Name: Viking 2 LanderThe biology experiment searched for the presence of Martian organisms by looking for metabolic products. Three distinct instruments (pyrolytic release (PR), labeled release (LR), and gas exchange (GEX)) incubated samples of the Martian surface under a number of different environmental conditions. In some instances a sample was heat sterilized and reprocessed as a control. The PR, or carbon assimilation, instrument sought to detect the photosynthetic or chemical fixation of CO2 or CO containing C-14. The samples were incubated for several days in the presence of the radioactive gas mixture, some samples with simulated sunlight and some without. Next, each sample was heated to 120 C to remove unreacted CO2 and CO. The soil was pyrolized at 650 C and any organic products were collected in an organic vapor trap (OVT). Finally, the trap was heated to combust the organic material to CO2 and any evolved radioactive gas was measured. The LR experiment sought to detect metabolic processes through radiorespirometry. Liquid nutrients labeled with radioactive carbon were added to the samples and the atmosphere above was continuously monitored to detect any radioactive gases released from these nonvolatile nutrients. The GEX measured the production and/or uptake of CO2, N2, CH4, H2, and O2 during incubation of a soil sample. The sample was sealed and purged by He, then a mixture of He, Kr, and CO2 was introduced as an initial incubation atmosphere. After the addition of a selected quantity of a nutrient solution (saturated with the diagnostic gas, neon), the sample was incubated. At certain intervals, samples of the atmosphere were removed and analyzed by a gas chromatograph with a thermal conductivity detector.
Mass: 15 kg
Power (avg): 15 W
Questions and comments about this experiment can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Harold P. Klein | Team Leader | NASA Ames Research Center | |
Dr. Alexander Rich | Team Member | Massachusetts Institute of Technology | |
Dr. Joshua Lederberg | Team Member | Stanford University | jsl@mail.rockefeller.edu |
Dr. Norman H. Horowitz | Team Member | California Institute of Technology | nhorowit@cco.caltech.edu |
Mr. Gilbert V. Levin | Team Member | Biospherics, Inc | gillevin@biospherics.com |
Mr. Vance I. Oyama | Team Member | NASA Ames Research Center |