Three Years on the ISS Exterior: Deinococcus radiodurans Survives Space Exposure, Igniting Massapanspermia and Planetary-Protection Debate

To the point

Led by Akihiko Yamagishi, Deinococcus radiodurans survived years on panels outside the ISS with inner cells shielded by outer layers, fueling discussions of microbes traveling between planets and the idea of massapanspermia, though Nathalie Cabrol and Natalie Grefenstette caution this is not proven and planetary protection remains crucial.

Scientists Discover Exposed Bacteria Can Survive in Space for Years
smithsonianmag.com

Scientists Discover Exposed Bacteria Can Survive in Space for Years

An experiment conducted outside the International Space Station leads to a controversial theory about how life might travel between planets