Moss on Mars

Long-duration space missions will require closed-loop life support systems that can regenerate oxygen and purify water while recycling waste. A recent ESA Discovery project led by the University of Naples Federico II explored whether aquatic mosses – often found in aquariums – could combine oxygen production with water filtration in compact, low-maintenance systems.

Bioregenerative Life Support Systems (BLSSs) rely on living organisms to sustain human crews during extended missions. Higher plants and microalgae have been studied extensively, but each has limitations. Higher plants require large and complex cultivation systems, while the challenges facing microalgae include biofilm formation, contamination, and uneven light distribution in photobioreactors.

Aquatic mosses present an intriguing alternative. These non-vascular plants have simple structures, require minimal inputs, and are already known as effective biofilters. The 'Moss on Mars' project examined three aquatic moss species – Taxiphyllum barbieri, Leptodictyum riparium, and Vesicularia montagnei – under controlled environmental conditions mimicking those in space habitats. Based on the results, the team selected T. barbieri for further tests exploring its responses to ionising radiation, a key challenge for any space-based organism.

The project demonstrated the potential of aquatic mosses as versatile, low-maintenance organisms capable of performing multiple ecological functions in resource-constrained environments – both in space and for terrestrial water treatment applications.