5 February 2002 Periodic analysis of the Viking Lander Labeled Release experiment
Author Affiliations +
Did Viking Lander biology experiments detect life on Mars? The strongest evidence for biology resulted from the Labeled Release (LR) experiment1. A radiolabeled (14C) nutrient solution was added to a Martian soil sample and the subsequent evolution of radioactive gas was observed. Flight data showed an initial release of labeled gas followed by strong periodic fluctuations in amount of gas in the headspace above the soil, superimposed on a slow rise in release. Current analyses show, at steady state, these fluctuations exhibit a periodicity of 24.66+/- 0.27 hr, statistically indistinguishable from the Martian solar period. The gas fluctuation appears synchronized to a mean 2 degree(s)C periodic fluctuation in internal temperature in the experimental chamber, which in turn is synchronous with almost 50 degree(s)C daily fluctuations in ambient Mars surface temperature. Calculations based on LR data indicate that the daily gas fluctuation amplitude could be in part accounted for by change in temperature-dependent soil solubility of CO2, but total amount of gas accumulated cannot be accounted for in this way. Recent observations of circadian rhythmicity in microorganisms and entrainment of terrestrial circadian rhythms by low amplitude temperature cycles argue that a Martian circadian rhythm in the LR experiment may constitute a biosignature.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joseph D. Miller, Joseph D. Miller, Patricia A. Straat, Patricia A. Straat, Gilbert V. Levin, Gilbert V. Levin, } "Periodic analysis of the Viking Lander Labeled Release experiment", Proc. SPIE 4495, Instruments, Methods, and Missions for Astrobiology IV, (5 February 2002); doi: 10.1117/12.454748; https://doi.org/10.1117/12.454748


A planetary quarantine laboratory on the moon
Proceedings of SPIE (November 01 2004)
A circadian biosignature in the labeled release data from Mars?
Proceedings of SPIE (September 22 2005)
Scientific logic for life on Mars
Proceedings of SPIE (February 05 2002)
Solving the problems with chirality as a biomarker for alien...
Proceedings of SPIE (September 07 2010)
Sterile robotic Mars soil analyzer
Proceedings of SPIE (February 26 2003)

Back to Top