Disaster could strike at any moment. For hundreds of millions of years, life on Earth has had to contend with a litany of existential threats: wayward asteroids, deadly pandemics, frigid ice ages and hellish volcanic eruptions. In modern times, the threat of climate change perhaps looms largest.
According to the Intergovernmental Panel on Climate Change (IPCC), almost 1 in 5 land species have a high risk of going extinct by 2100 if global temperatures continue to climb unchecked.
The situation in the oceans is just as dire, as marine biologist Dr Mary Hagedorn, an expert on coral reefs from the Smithsonian's National Zoo, knows all too well. “They are disappearing faster than we can save them,” she says.
Hagedorn's day-to-day work focuses on cryopreserving the coral, including its sperm cells and larvae. By using liquid nitrogen to store them in a deep freeze, at least they won't disappear forever. “Once the material is properly cryopreserved, it is basically in stasis for all time,” she says. One day they could be reintroduced to help stabilise ecosystems.
Her success with cryopreserving coral has led Hagedorn to what, at first, might seem an outlandish proposal recently unveiled to the world. A vault on the Moon containing alive, but frozen samples of cells from the species most important in rebuilding ecosystems.
From frozen coral to a bio-vault on the Moon
Could this plan actually work? Hagedorn points to the existing Global Seed Vault in Svalbard, Norway, inside the Arctic Circle. Currently home to over a million different seed species, it's there to safeguard our food supply against catastrophic loss of some of the world's most important crops. It is a so-called ‘passive repository’, meaning it requires no people or energy to maintain the seeds at -18°C.
However, deep-freezing live cells requires a temperature below -196°C, the boiling point of the liquid nitrogen used in cryopreservation. “There is no place on Earth cold enough to have a passive repository that must be held at -196°C,” says Hagedorn, “so we thought about... the Moon.”
The lunar south pole could be an ideal spot because there are parts of it that are permanently in shadow and therefore local temperatures are always below this crucial temperature. There may also be ancient and deep lava tubes at mid-lunar latitudes that are equally as cold.
Other than getting too warm, the other issue that could degrade the samples is radiation. Without a magnetic field for protection, the Moon is constantly bombarded by high-energy particles from the Sun and the wider galaxy.
According to Hagedorn, burying the samples at least two metres below the dusty lunar surface should provide adequate protection. “If we defend against those issues, samples could be stable for centuries,” Hagedorn says.
Hagedorn's proposal mainly focuses on fibroblast cells. They form the connective tissue that helps support and protect organs, can be readily obtained from skin samples and have the remarkable property of being reprogrammable.
Biologists can change them into stem cells, which in turn have the ability to develop into many different types of cells, including those belonging to the heart, brain and blood. In other words, they could be used for cloning. “Fibroblast cells are the perfect choice for this biorepository,” Hagedorn says.
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As the team's experience and expertise grow, they also plan to look at sending reproductive cells such as eggs and sperm. Either way, the idea is that cells from at least one hundred individuals of each selected species would travel to the Moon vault to ensure enough genetic diversity in any reintroduced population.
This may all sound more than a little futuristic, but we already know how to turn fibroblasts into stem cells in space. In fact, experiments on the International Space Station have shown that it's easier to achieve in microgravity than it is on Earth.
Hagedorn sees Low Earth Orbit as the perfect testing ground for her plan. “Hopefully we can test something out on the ISS in the next five years and then work from there,” she says.
First, we need to confirm that these cells can survive the kind of radiation environment they'll experience both on the Moon and on the way there and back again. Hagedorn has identified one particular species as the proverbial guinea pig: the Starry Goby. These small, carnivorous reef fish are often used in aquaria.
First steps
In 2023, Hagedorn collected ten Starry Gobies from Kane’ohe Bay in Hawai’i. The team cryopreserved two pelvic fins from each fish, including their fibroblast cells. Hagedorn is now looking for ways to get these cells into space to test out their hardiness and experiment with different types of protective packaging.
The team are currently waiting to find out if they've secured a spot on Griffin 1, a private mission to the Moon's South Pole planned as soon as 2025.
So, which other species might make the cut? “We want to save the function of Earth's ecosystems not endangered species, per se,” Hagedorn says. That means prioritising species for their ability to help us rebuild the environment, not necessarily just how threatened they are.
Among the important groups identified by Hagedorn are so-called ‘environmental engineers’. These are animals that modify and improve their surroundings. Think worms, which boost the structure of soil, or oysters, which each filter hundreds of litres of seawater a day.
Then there are the primary producers, organisms that acquire their energy from non-living sources, such as sunlight. Examples include algae, plants and some bacteria. Pollinators, such as bees and other insects, will also likely make the cut as they're needed to help the primary producers reproduce.
It would be wrong, however, to think that rebuilding Earthly ecosystems is the only aim of the lunar biorepository. Hagedorn also has one eye on the future of human space exploration. If all goes to plan, the first boots will walk on Mars by the middle of this century.
Future generations may well have plans to engineer the Martian environment to make it more habitable. Other groups are included in Hagedorn's shortlist for this very reason. They include extreme environment fauna – animal species that thrive in trying conditions that other species couldn't handle.
So, how long could this all take? “Given enough money and NASA backing, we could do this now,” Hagedorn says, pointing out that the Apollo Moon landings were a far bigger jump in science and technology than her proposal. “We know how to do this and can do this and will do this, but it may take decades to finally achieve.”
Prof Ian Crawford, from Birbeck, University of London, who is not involved in the vault, sees the value in the plan but is a bit more cautious. “It's not currently feasible but could become so as human activities on the Moon ramp up,” he says.
He also thinks that a depth of 10 metres instead of two would be required in order to adequately protect from radiation. “This will require developing a sophisticated drilling capability,” he says.
Nothing in space exploration is ever easy, but we've shown time and again how adept we are at overcoming obstacles and making history. If we do end up burying a bio-vault beneath the lunar dust then, depending on how the next century unfolds on Earth, future generations may well be thankful that we did.
About our experts
Dr Mary Hagedorn is a senior research scientist at Smithsonian's Zoo and Conservation Biology Institute. Her work focuses on aquatic ecosystems around the world from the Amazon to Africa and has been published in the Journal of Visualized Experiments, Bioscience and Advanced Science.
Prof Ian Crawford is based at Birkbeck University's School of Natural Sciences. His work focuses on lunar science and exploration and astrobiology and has been published in Planetary and Space Science, Nature Astronomy and Astronomy and Computing.
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