The pyrolytic release experiment - Measurement of carbon assimilation

The pyrolytic release experiment or carbon assimilation experiment is one of the three modules in the biology instrument on the 1976 Viking landers, which aims at detecting microbial life in Martian surface materials. The paper examines this experiment relative to the scientific assumptions in developing the test, the laboratory investigation supporting the experimental concept, and the operation and testing of the flight instrument. The only assumptions made are that the Martian species are adapted to function in their arid environment and that atmospheric CO2 or CO are assimilated by the species. Although the test is primarily designed to measure photoassimilation of CO2 or CO, the assimilation of these gases in heterotrophic or chemolithotrophic metabolism could also be detected. A new possibility for a carbon cycle on Mars is discussed.