Is it OK to leave objects on the Moon?

US flag on Moon Image copyright AP

A British-led group wants to fund a Moon mission with public donations. Contributors to the Lunar Mission One project will have their photos, text and videos buried beneath the moon's surface. But is it legal - or acceptable - to drop stuff on the Moon and just leave it there, asks Mike Wendling.

The key international treaty that governs the Moon has nothing to say about littering, says New York-based lawyer Timothy Nelson. The 1967 Outer Space Treaty does require explorers to avoid "harmful contamination" of the Moon and other celestial objects. But it also bans territorial claims in space, and as a result there is no central authority which enforces laws - against littering or anything else - on the lunar surface.

The Moon is already strewn with rubbish - exploration has left its surface dotted with everything from abandoned modules to golf balls to an empty vomit bag from Apollo 11.

Nasa keeps a list of all human detritus on the Moon. And in fact America's space agency tries to protect the lunar remains of the Apollo missions, citing their "historical and scientific value".

Few space law cases have ever been tested, Nelson says, but it could be argued that leaving traces of missions is allowed under the Outer Space Treaty's dedication to keep space open to peaceful exploration.

"The idea of a time capsule is not really all that different," he says.

So it may be legal - but is it ethically right to clutter the Moon with debris?

"Our knowledge of the effects of landing, drilling, and burying a time capsule are largely unknown and perhaps unknowable," warns Margaret McLean of the Markkula Center for Applied Ethics at Santa Clara University in California.

The idea of environmentalism might seem odd applied to the vastness of space. But some ethicists argue Earthbound principles still apply.

McLean says projects like Lunar Mission One should follow certain ethical guidelines - for instance valuing the Moon for its own sake, not as storage space, and protecting its natural state.

"I applaud the goals of creating enthusiasm and joy in space exploration and the inspiring of the next generation of space scientists," she says, "but likely environmental damage and lunar litter is too high a price to pay."

Subscribe to the BBC News Magazine's email newsletter to get articles sent to your inbox.