Gil Levin Forty years ago today, the first of two landing probes of NASA’s Project Viking touched down on planet Mars. Discover contributor Dr. David Warmflash spoke with Dr. Gilbert Levin, whose Labeled Release (LR) experiment was one of three instruments delivered by the Viking landers to look for Martian microorganisms in 1976. At age 92, Levin is the only survivor of the three biology experimenters and he’s looking ahead to 2020 when he hopes to have another instrument on the Martian surface looking for life.
A model of a Viking lander on the surface of Mars. (Credit: NASA) Discover: How did the Labeled Release life detection experiment get started?Gilbert Levin: When I was a public health engineer for the state of California in 1951, one of my responsibilities was to determine the sewage-polluted region of Santa Monica Bay and set up quarantine limits for swimmers. To determine the constantly shifting polluted area caused by the discharge of some 300 million gallons a day of Los Angeles’ only partially treated sewage, I took samples of the Bay water back to the lab for bacteriological assay. The problem was the assay took up to three days. The microorganisms had to reproduce themselves enough to make visible bubbles in test tubes from the gases they exhaled. Reporting the results to me took three more days. By the time I had the analyses, they were of historical value. I got the idea of cutting down on the assay time by incorporating radioisotopes into the microbiological test media.
