Engineers propose solar-powered lunar ark as ‘modern global insurance policy’

University of Arizona researcher Jekan Thanga draws scientific inspiration from an unlikely source: the biblical story of Noah’s Ark. Instead of two of each animal, however, its solar-powered ark on the moon would store cryogenically frozen seeds, spores, sperm, and egg. samples from 6.7 million Earth species.

Thanga and a group of his undergraduate and graduate students outline the concept of the lunar market, which they call a ‘modern global insurance policy’, in a paper presented at the IEEE Aerospace Conference over the weekend.

“The earth is a volatile environment by nature,” said Thanga, a professor of aerospace and mechanical engineering at UArizona College of Engineering. “As humans, we had a call about 75,000 years ago with the Toba supervolcanic eruption, which caused a cooling-off period of 1,000 years and, according to some, corresponds to an estimated decline in human diversity. Because human civilization is like that.” has a large footprint, should it collapse, it could have a negative effect on the rest of the planet. ‘

Climate change is another source of concern: if sea levels continue to rise, many arid places will go underwater – including the Svalbard Seed Bank, a structure in Norway that contains hundreds of thousands of seed samples to protect against biodiversity disaster. Thanga’s team believes that storing samples in another celestial body reduces the risk of biodiversity being lost if one event were to cause total destruction of the earth.

Completely tubular

In 2013, scientists discovered a network of about 200 lava tubes just below the lunar surface. These structures formed billions of years ago when streams of lava melted through soft rock underground and formed underground caves. On Earth, lava tubes are often similar to subway tunnels and can be eroded by earthquakes, plate tectonics and other natural processes. This network of lunar lava tubes is about 100 meters in diameter. Approximately about 3 to 4 billion years untouched, they can provide shelter from solar radiation, micrometeorites and surface temperature changes.

The idea of ​​developing a lunar base or a human settlement on the moon has been around for hundreds of years, and the discovery of the lava tube has renewed the space community’s enthusiasm for the concept. But the moon is not exactly a hospitable environment where people can spend long periods of time. There is no water or air to breathe, and it is about 25 degrees Celsius, or minus 15 degrees Fahrenheit. It is also not a very eventful place.

On the other hand, the same features make it an excellent place to keep monsters that have to stay very cold and undisturbed for hundreds of years at a time.

Building a lunar ark is not a small undertaking, but according to a quick, quick calculation of the envelope, Thanga said it is not as overwhelming as it may sound. Transporting about 50 samples of each of 6.7 million species requires about 250 rockets. It takes 40 rockets to build the International Space Station.

“It’s not crazy,” Thanga said. “We were a little surprised.”

Cryogenics and quantum levitation

The mission concept builds on another project previously proposed by Thanga and his group, in which miniature flying and jumping robots called SphereX enter a lava tube in teams. There they would collect samples of regolith, or dust and loose rock, and gather information about the layout, temperature, and composition of the lava tubes. This information can inform the construction of the lunar base.

The team’s model for the underground ark contains a set of solar panels on the lunar surface that will provide electricity. Two or more elevator shafts will lead to the facility, where petri dishes are housed in a series of cryogenic preservation modules. An additional goods lift will be used to transport construction materials so that the base inside the lava tubes can be extended.

To be cryopreserved, the seeds must be cooled to minus 180 C (minus 292 F) and the stem cells must be kept at minus 196 C (minus 320 F). As a reference to how cold it is, the Pfizer COVID-19 vaccine should be stored at minus 70 C, or minus 94 F. The fact that the lava tubes are so cold and that the samples should be even colder means that there a the risk that the metal parts of the base may freeze, jam or even cold weld. On Earth, commercial airlines stop working when ground temperatures reach minus 45 to minus 50 C (minus 49 to minus 58 F).

However, there is a way to take advantage of the extreme temperatures by using another-world phenomenon called quantum levitation. In this process, a cryocooled superconductor material – or a material that transfers energy without losing any heat, as a traditional cable does – floats above a powerful magnet. The two pieces are connected at a fixed distance, and wherever the magnet goes, the superconductor follows.

“It’s like they were locked by strings, but invisible strings,” Thanga said. “When you get cryogenic temperatures, strange things happen. Some of them look just like magic, but are based on proven physics principles at the edge of our understanding.”

The team’s ark design uses this phenomenon to float the shelves of samples above metal surfaces and to navigate robots through magnetic tracks through the facility.

There is much more research on the construction and use of the ark, from the investigation into how the preserved seeds can be affected by a lack of gravity, to a plan for the basic communication with the earth.

“What amazes me about projects like this is that it makes me feel that we are getting closer to a spatial civilization, and to a not-too-distant future where humanity will have bases on the moon and on Mars,” said Álvaro Díaz – Flores Caminero, a doctoral student in UArizona, who led the thermal analysis for the project. “Multidisciplinary projects are difficult because of their complexity, but I think the same complexity is what makes them beautiful.”

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