James Woodford in New Scientist: 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.