Q: Have scientists sent experiments like the “Wolf trap” to Mars to search for life?
A: The “Wolf trap” was a life-detection instrument designed by American microbiologist Wolf Vishniac for the Viking mission, which landed on Mars in 1976. Due to budget cuts, it was not included on either lander. The principle of the Wolf trap was to bring martian dust into a tube containing nutrients in liquid form. The instrument would then monitor the state of the liquid; if its pH or cloudiness changed after the martian dust was introduced, this would be an indication of life. Three other culture-based experiments were part of the Viking biology payload instead, but none measured direct changes in a liquid that was designed to support growth.
Modern approaches to life detection do not rely on growing organisms in nutrients but are instead based on the direct detection of the biomolecules that compose the organisms, such as DNA, the alien equivalent of DNA, or the products of organisms’ metabolism.
Chris McKay
NASA’s Ames Research Center, Moffett Field, California
