Thanga and his team sketched out a system that would utilize solar panels and batteries to provide energy to lower the temperature inside the lava tube to the deep freeze needed to create their lunar ark. That’s a key difference between Thanga’s design and Hagedorn’s thought experiment. While Thanga’s group would aim to actively nippy the ark, Hagedorn and the Smithsonian team envisioned a repository that uses the moon’s natural features to keep samples cryogenically frigid.
“The idea behind our proposal is that to the extent we could do this, it would be passive,” Parenti said. She noted that people have long speculated about the idea of building something that would store materials on the moon, but all of the ideas have required a crew to maintain them.
To passively maintain a perpetual deep freeze, they proposed building a repository at the moon’s south pole, where celestial geometry has converged inside some craters to create areas of indefinite shadow, and temperatures can drop to -196 degrees Celsius. Such conditions would mean samples could be stored without the need for a crew, with maintenance provided only by rovers and robotics.
While in theory all of this makes these indefinite polar shadows ideal for such a project, “we don’t know what this place is,” Thanga replied. Just last month, NASA the mission was canceled It would be the first rover to explore the pole, in part because of the technical challenges. “That’s one of the ironies,” Thanga said. “It’s not far from Earth, but it’s probably one of the most extreme places in the entire solar system.”
Fitzpatrick, however, is confident that NASA’s current lunar roadmap will provide ample opportunity to explore and understand these obscure polar regions, including planned mission for later this year, where it is planned to land ridge overlooking the polar shadowBut as NASA looks to explore these regions, Thanga noted, it’s possible we might just learn more about how arduous it is to exist and operate in such frigid.
“Just operating in cryogenic conditions, that’s not trivial at all,” Thanga said. “Mechanical things do strange things. They can freeze, seize, whatever, in space conditions. Even in moderately cold conditions in a vacuum, we have a phenomenon called cold welding,” where two pieces of metal fuse on contact.
Thanga says it would make more sense to build the ark in a lava tube, since his planetary scientists predict that such tubes would be very similar to those we have on Earth, albeit much colder. That way, scientists and engineers would know what to expect and how to prepare.
Like Hagedorn’s concept, the price and timeline have not yet been finalized. But Thanga expects that once the design is finalized (which could take years) it could be built and assembled faster and cheaper than the International Space Station.