Huge mile-scale space station with ‘simulated gravity’ could be launched from a single rocket

Artificial gravity remains the stuff of science fiction. But coping with the absence of gravity causes significant problems for many astronauts, ranging from bone deterioration to loss of sight. An alternative method that could eliminate some of these problems is “simulated gravity,” which uses a rotating structure to create centrifugal force that would have the same effect on the body as gravity. Whether or not this would solve the problems caused by the lack of gravity remains to be seen. Always,[{” attribute=””>NASA seems keen on the idea – to the tune of a $600,000 NASA Institute for Advanced Concepts (NIAC) Phase II grant to a team from Carnegie Mellon University (CMU) and the University of Washington (UW) who is looking to develop a structure that can simulate full Earth gravity and be launched in a single rocket.

The project in question is “Kilometer-Scale Space Structure from a Single Launch,” which was initially admitted to the NIAC program last year. Over the past year, they successfully completed a Phase I project where they “analyze[d] a mission concept analogous to the Lunar Gateway” that could deploy in a mile-long structure. Having met NASA’s expectations for this program, the team, led by Professor Zac Manchester of CMU and Jeffery Lipton of UW, were recently accepted as 2022 NIAC Fellows.

Slide from an NIAC presentation on structure at the kilometer scale. Credit: Zac Manchester and Jeffery Lipton

This is not the first NIAC project to tackle the idea of ​​large structures in space, however. NextBigFuture reported in 2021 about a dozen NIAC-funded projects that would take advantage of new metamaterials to dramatically increase their size once in space. NASA isn’t alone in supporting them either: the National Science Foundation of China has supported efforts to develop a kilometer object up to $2.3 million.

These large structures require significant investment, but they also have significant potential benefits. There are two options for achieving Earth’s gravity using centrifugal forces. Either spin very, very fast, or have a very, very large axis of rotation. Unfortunately, humans, being the squishy bags of water that they are, don’t really like spinning very fast for long periods of time, as anyone who’s ever gotten sick at a carnival can tell you. Science places this RPM limit for discomfort at around 3 RPM. Thus, to rotate at less than 3 rpm while benefiting from simulated Earth gravity, the structure itself must be one kilometer long.

So far, it has proven impossible to fit so much hardware into a single rocket launch. But, Dr Manchester and his team believe they have found a potential solution to the impossible problem – a “high expansion rate deployable structure” or HERDS. The HERDS themselves utilize two new mechanical innovations – shear auxetics and branching scissor mechanisms.

Shear auxetics are a new type of metamaterial that expands when pulled in a chiral pattern. The level of chirality can also control the stiffness of the material. They seem to be gaining traction in robotics applications as linear actuators and grippers, but their use case in space has yet to be proven.

Video showing shear auxetics in action. Credit: Lillian Chin YouTube channel

Branching scissor mechanisms are another way to deploy a larger structure from a compact structure. Originally developed by Youtuber and artist Henry Segerman, branching scissor mechanisms snap into much larger structures from more compact ones. You can even buy a demo child yourself from Shapeways, but again, the structures haven’t been used in space yet.

Video featuring branching scissor mechanisms. Credit: Henry Segerman

Ideally, one or both of these systems would work to create the structure of a kilometer-scale space habitat capable of spinning at a speed that would sufficiently simulate Earth’s gravity. Drs. Manchester, Lipton and their team believe they can use these technologies to create tubular structures that can expand up to 150 times their size when packed into a rocket fairing. It’s a lofty goal, but they have the time and the funds to work on it. By the end of NIAC’s two-year study period, if the idea is fleshed out enough, these new technologies might even have time to be incorporated into plans for the Lunar Gateway.

Originally published on Universe today.