Should we put a frozen backup of Earth’s life on the moon?

A backup of life on Earth could be kept safe in a permanently dark location on the moon, without the need for power or maintenance, allowing us to potentially restore organisms if they die out.

Mary Hagedorn at the Smithsonian’s National Zoo & Conservation Biology Institute in Washington DC and her colleagues have proposed building this lunar biorepository as a response to the extinctions occurring on Earth.

The plan has three main goals: to safeguard the diversity of life on Earth, to protect species that might be useful for space exploration, such as those that could provide biomaterials for food or filtration, and to preserve microorganisms that may one day be needed for terraforming other planets.

Hagedorn says the team wanted to identify a location where no people or energy would be required to keep cryogenically frozen, living cells colder than -196°C – the temperature at which nitrogen is a liquid and all biological processes are suspended.

“There is no place on Earth cold enough to have a passive repository that must be held at -196°C, so we thought about space or the moon,” says Hagedorn.

She says the team settled on the lunar south pole due to its deep craters with permanently shadowed and cold regions. Burying samples about 2 metres below the surface would also keep them safe from radiation, she says.

Previous attempts at building secure biorepositories have had mixed success. The Svalbard Global Seed Vault in Norway lies in the Arctic and was constructed to be kept permanently below -18°C by the surrounding permafrost, but climate change and warming temperatures are now threatening its long-term security.

Biorepository sites elsewhere in the world, especially those close to cities, rely on human power sources and are also susceptible to geopolitical upheavals.

Andrew Pask at the University of Melbourne, Australia, who is building a repository for Australian species, is keen on the idea. “We would love to see our samples at duplicate facilities to ensure their safety and, at this point, the moon does seem the safest potential location,” he says.

But Rachael Lappan at Monash University in Melbourne says there are many challenges and disadvantages to using the moon, not least accessing it to add or withdraw samples. It may be better to have samples on Earth with a lot of redundancy so that if one repository fails others are still available, she says.

“I would want to see compelling evidence that we could make use of the repository if it was needed,” she says.

Even if this lunar repository were never used, Alice Gorman at Flinders University in Adelaide, Australia, sees value in conserving human artefacts in space – perhaps even for any alien civilisations to one day access.

“Repositories, whether they’re cryogenically frozen living tissue or DNA, or the entirety of Wikipedia saved on a high-density nickel disc, are going to be just like the Voyager spacecrafts’ golden records,” says Gorman, referring to metal discs describing humanity that are attached to these craft, which are now leaving the solar system.