Lichen can survive the hostile conditions of space, according to a study published by a team of biologists, lending more support to the theory that life arrives on planets via near-Earth objects.
The study, published in the June 2012 issue of Astrobiology, details how the lichen was exposed to (and survived) electromagnetic and cosmic radiation, a space vacuum and extreme temperatures during the European Space Agency’s (ESA) Expose-E mission. The paper says the significant findings provide evidence for the panspermia hypothesis that organisms travel from planet to planet on meteors and asteroids.
“We are exploring the limits of life,” explains René Demets, a biologist at ESA. “These organisms go into a dormant state waiting for better conditions to arrive.”
The mission launched in February 2008, with the European Technology Exposure Facility installed outside the International Space Station, and a follow-up mission was carried out in 2009. Both experiments lasted a year and a half.
Installed on the Exposure Facility were three trays — two built to test the organisms’ ability to survive in a space vacuum and up against electromagnetic radiation, cosmic ionising radiation and temperature change, and a third tray that simulated the atmospheric conditions on Mars’ surface. Each tray had several compartments to increase the range of test samples. The trays were fitted with 8mm-thick windows that would expose the lichen to various elements.