Antarctic lichen from the McMurdo Dry Valleys has proven its remarkable toughness by surviving 18 months on a platform outside the International Space Station (ISS). This experiment, conducted on the ISS’s Columbus module, provided insights into life’s potential to survive in extreme conditions, including those on Mars.

In a simulation of Martian conditions, more than 60% of the lichen cells survived, with their membranes intact. Rosa de la Torre Noetzel of Spain’s National Institute of Aerospace Technology (INTA) highlighted this as a critical finding in demonstrating lichen’s resilience. However, survival rates dropped to 35% when exposed to outer space, a testament to the hostile nature of the environment.

Outer space is inherently hostile to carbon-based life. It combines extreme temperatures, intense radiation, and high-speed micrometeoroids, making survival seemingly impossible for most organisms. For instance, astronauts on a six-month mission are exposed to up to 2,000 millisieverts of radiation, which is many times higher than the dose received by Chernobyl cleanup workers.

This experiment is not the first to showcase lichen’s ability to withstand harsh environments. In 2005, lichens were exposed to space aboard a European Space Agency module attached to a Russian satellite for 16 days. Remarkably, they retained their photosynthetic activity despite exposure to lethal UV and cosmic radiation levels.

Lichen’s extraordinary resilience sets it apart from many other microorganisms, which often fail to survive similar exposure. This study suggests that lichen could serve as a model for studying life’s potential on Mars or other extraterrestrial environments.

These findings lend credibility to the idea that life forms might exist in harsh conditions beyond Earth, offering critical insights into planetary habitability and astrobiology.