Fungal strains in space spark worry

NASA found fungal strains that survive even its most stringent sterilization efforts, suggesting Earth microbes may already be living on Mars.

When exploring worlds which could plausibly harbor life — Enceladus, Europa, Mars, Titan — space agencies employ protocols to prevent Earth-based microbes contaminating any biology elsewhere.

The existence of near-unkillable fungi makes future Mars rover missions more fraught and past ones potential seeds of terrestrial life on the red planet. Titan may likewise be compromised: When visited by the Cassini-Huygens orbiter in 2004, no one realized Saturn’s moon had liquid oceans and was thus a promising candidate for life, so the probe was not fully sterilized. The little spacecraft “might be seeding life,” a mission scientist told Flagship’s Tom in 2017.