Living and working in space for extended periods of time presents a number of challenges. These include radiation, as locations beyond Earth’s protective magnetosphere are exposed to greater levels of solar and cosmic rays. There is also the need for self-sufficiency, as lunar or Mars bases are too far away to rely on regular resupply missions like the International Space Station (ISS). Finally, there is the matter of low gravity, which is particularly pressing for long-term missions and habitats beyond Earth. If the future of humanity really lies in space, we must devise solutions to this issue in advance.
A popular idea is to create rotating habitats in space that simulate artificial gravity, such as the Pinwheel Station or the O’Neill Cylinder. Another proposal from a team of Japanese researchers calls for something more daring: a rotating habitat on the moon. On July 5th, representatives from Kyoto University and Kajima Corporation (one of the oldest and largest manufacturing companies in Japan) announced that they will be working together to conduct a study on this idea and how it could make humanity’s plans for life on the moon and Mars a reality.
The study is a collaborative effort between Kyoto University and Kajima Corporation (one of Japan’s oldest and largest manufacturing companies). The announcement was made during a press conference covered by Kansai TV NEWS and shared via their YouTube channel. Here, Professor Yosuke Yamashiki of Kyoto University and Takuya Ohno – the head of the Architectural Design Department at Kajima Construction’s Kansai Branch – shared a video of the proposed “artificial gravity facility” for life on the moon and Mars.
The effects of microgravity on human physiology are well documented. Thanks to many experiments involving long stays on the ISS, which includes NASA’s famous Twin Study, it has been found that astronauts will experience loss of muscle mass and bone density. Recent research has also shown that the loss of bone strength is something that astronauts never fully recover from. Other noted effects include changes in cardiovascular health, organ function, vision, psychological effects and gene expression.
Unfortunately, there is currently no research into the effects of microgravity (or low gravity) on reproduction and early child development. This must be addressed if astronauts and regular folk hope to live on the Moon, where the surface gravity is 16.5% (0.165 g) of that of Earth. On Mars, where the surface gravity is about 38% (0.385 g) that of Earth, the situation is slightly better—but by no means ideal. A common suggestion is that structures rotating to create centripetal force would simulate Earth’s gravity—9.8 m/s2, or 1 g.
That’s the idea behind the facility known as Lunagrass, which would allow astronaut crews to live and work in simulated Earth gravity. As Professor Yamashiki explained:
“Mars and the moon are much less (surface gravity) than Earth. I wonder if humans will eventually live in these places… It is not known if mammals can reproduce and develop normally in a low-gravity space like the moon. The gravity inside ‘Lunagrass’ is the same as that of earth, and it is possible to give birth, and if you live here, you can maintain a body that can return to Earth at any time.”
As the video shows, the concept is similar to an O’Neill cylinder, except that it stands and rotates on its side and tapers at the bottom (creating a funnel shape). The ‘funnel’ is supported by a large lattice structure that extends across the base to distribute the weight of the installation over a larger area. Winding around the base structure is a track that shows a high-speed train responsible for transport from the hopper to the lunar surface or between points in the interior.
Interior view of the Lunagrass rotating base. Credit: Kajima Construction
Inside the funnel, we see bodies of water, land masses with greenery and trees, what appear to be floating structures (the brown squares), and a transportation network that allows people to travel everywhere. The simulated people in the video are seen walking along the “walls” as if it were no different than walking on the surface of the Earth (there are even motorized boats moving on water.) At the base of the funnel, which is less subject to centripetal force power, there is a stagnant body of water with more boats traveling around.
Other ideas discussed in the presentation include an Earth-Moon transport (even interstellar) that would rely on the same principles to simulate artificial gravity while in space. These are known as ‘Luna Beagle’ and ‘Space Express’, respectively. The animation shows what the first one would look like, a hexagonal vessel with modules extending from a central radius that rotates to provide artificial gravity to everyone inside.
Professor Yamashiki said, “Also, research has begun on transportation methods that use ‘artificial gravity.’ gravity (1G) environment like Earth while moving. [Space Express] it needs a lot of acceleration and I think it’s better to tow it by rocket.”
However, there are obvious issues of cost and the inevitable engineering challenges of building this type of structure on the moon. For example, during the presentation, the topic of in-situ resource utilization (ISRU) and how this structure will be built did not come up. Would they be assembled on Earth or in space, then sent to the Moon, or assembled in situ using regolith and other lunar resources? Would the work be done by autonomous robots, human crews remotely operating machinery on the surface, or a combination of the two?
Animation of ‘Luna Beagle’ passing between Earth and Moon. Credit: Kajima Construction
As Ohno admitted, the Lunagrass concept is “a dream story” at this point and not an actual mission architecture. But, he added, it’s a serious idea and could well be feasible in the near future. As humanity embarks on a renewed era of space exploration that includes plans for permanent habitats on the moon and Mars, ideas like this play an important role.
“Of course, it’s not technical at all, but it’s very important to generate ideas at this stage,” he said. “If possible, I want to go to the moon. More specifically, I want to go to Mars. I want to realize the idea on the moon somehow in 2050.”
Predicting the efficiency of electrolysis that develops oxygen on the moon and Mars provided by Universe Today
Reference: To get artificial gravity on the moon, you’d need a giant rotating lunar base (2022 July 18) Retrieved July 18, 2022 by
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