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Science 17 December 1976:
Vol. 194. no. 4271, pp. 1322 - 1329
DOI: 10.1126/science.194.4271.1322
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Articles

Viking Labeled Release Biology Experiment: Interim Results

GILBERT V. LEVIN 1 and PATRICIA ANN STRAAT 1

1 Biospherics Incorporated, 4928 Wyaconda Road, Rockville, Maryland 20852

This report summarizes all results of the labeled release life detection experiment conducted on Mars prior to conjunction. Tests at both landing sites provide remarkably similar evolution of radioactive gas upon addition of a radioactive nutrient to the Mars sample. The "active" agent in the Mars sample is stable to 18°C, but is substantially inactivated by heat treatment for 3 hours at 50°C and completely inactivated at 160°C, as would be anticipated if the active response were caused by microorganisms. Results from test and heat-sterilized control Mars samples are compared to those obtained from terrestrial soils and from a lunar sample. Possible nonbiological explanations of the Mars data are reviewed along with plans for resolution of the Mars data. Although such explanations of the labeled release data depend on ultraviolet irradiation, the labeled release response does not appear to depend on recent direct ultraviolet activation of surface material. Available facts do not yet permit a conclusion regarding the existence of life on Mars. Plans for conclusion of the experiment are discussed.

Submitted on November 15, 1976


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Possible Surface Reactions on Mars: Implications for Viking Biology Results.
C. Ponnamperuma, C. PONNAMPERUMA, A. SHIMOYAMA, M. YAMADA, T. HOBO, and R. PAL (1977)
Science 197, 455-457
   Abstract »    PDF »
Scientific Results of the Viking Missions.
G. A. Soffen and G. A. SOFFEN (1976)
Science 194, 1274-1276
   Abstract »    PDF »


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