Your Celestial Companion

Searching for life on Mars means making sure we don't accidentally bring our own. A new model reveals exactly how long Earth microbes can survive the brutal journey. Searching for past or present life on Mars is the sole driving force behind every mission we send to the red planet, from orbiters to landers to rovers. However, there remains a persistent concern: forward contamination.

Growing potatoes in Martian dirt is the easy part. To survive years in deep space, astronauts need a perfectly balanced, multi-stage ecosystem—and if one piece breaks, everyone starves. When we imagine deep space farming, we picture Matt Damon in The Martian scratching a living out of regolith, or glowing hydroponic bays on a starship. But a new paper in Acta Astronautica by Tor Blomqvist and Ralph Fritsche reveals that producing food is just one fraction of the battle.

Dining on the Moon or Mars sounds like science fiction. But a new process recycling human waste into fertilizer is turning barren alien dust into fertile fields. To build a sustainable colony on the Moon or Mars, we must grow our own food. But the surfaces of these worlds are covered in regolith—a dusty, rocky material that is incredibly sharp, abrasive, and completely devoid of organic matter.