Life forms could survive ejection on asteroid debris

A Johns Hopkins study found a hardy desert bacterium survived pressures intended to simulate ejection from Mars and could withstand conditions associated with interplanetary transfer.

Tiny organisms tucked inside rock fragments launched by asteroid strikes may survive being ejected from one planet and travel to another, a Johns Hopkins University study reports. The researchers tested the desert bacterium Deinococcus radiodurans under pressures designed to mimic an asteroid-driven ejection from Mars. The work revisits the lithopanspermia idea that life can move between planets and highlights implications for planetary protection and space missions. The study was published in PNAS Nexus and received support from NASA’s Planetary Protection program. Key findings: - The team simulated impact and ejection pressures by sandwiching Deinococcus radiodurans between metal plates and firing a projectile at speeds up to 300 mph, producing about 1–3 gigapascals of pressure. - The bacterium survived nearly all tests near 1.4 gigapascals and showed roughly 60% survival at about 2.4 gigapascals, with greater cellular damage observed at higher pressures. - The pressures used are more than ten times the pressure at the bottom of the Mariana Trench and approach values estimated for some Martian ejection events. - The authors note that ejecta from Mars can reach nearby bodies such as its moons and that these results have implications for planetary protection rules that govern where spacecraft may land or return samples from. - The experiment focused on a particularly hardy microbe; the team plans further work to test repeated impacts and to study other organisms. Summary: The study shows a highly resilient desert bacterium can survive pressures comparable to those expected during large impacts and ejection from Mars, indicating microorganisms could endure some aspects of interplanetary transfer. The authors say the findings relate to planetary protection protocols and to how researchers think about the possible origins or distribution of life in the solar system. The research team intends to explore effects of repeated impacts and whether other organisms show similar resilience.