For the last 36 years the media told us that the Viking mission launched by NASA in 1976 didn’t find life on Mars or that Viking proved that Mars was dead. Well, that just was never true and NASA’s only official comment on the subject was that the experiment testing for life was inconclusive.
Viking used an experiment called Labeled Release or (LR) to detect the release of radioactive gas by organisms metabolizing nutrients laced with a radio active compound, if such organisms were in fact present in the Martian soil. This detection method was designed by Dr. Gilbert V. Levin in 1969 whom NASA later contracted for the Viking missions.