Robotic “SuperLimbs” could help astronauts who trip on the Moon

Standing back up after you’ve fallen down can be hard enough here on Earth, let alone while wearing a cumbersome spacesuit in the low-gravity environment on the Moon.

So now engineers from Massachusetts Institute of Technology (MIT) are developing a pair of robotic “SuperLimbs” that can physically support an astronaut and lift them back on their feet after they fall.

The system could help astronauts conserve energy and extend missions on the lunar surface.

“Astronauts are physically very capable, but they can struggle on the Moon, where gravity is one-sixth that of Earth’s but their inertia is still the same,” says Harry Asada, professor of mechanical engineering at MIT.

“Furthermore, wearing a spacesuit is a significant burden and can constrict their movements.”

The new design is the latest application of SuperLimbs, which Asada first developed about a decade ago and has since adapted for a range of applications.

“In communications with NASA, we learned that this issue of falling on the Moon is a serious risk,” Asada says.

“We realised that we could make some modifications to our design to help astronauts recover from falls and carry on with their work.”

The re-designed the system consists of two multijointed robotic arms that can extend from a backpack, which would also carry the astronaut’s life support system, along with the controller and motors to power the limbs.

A control system directs the limbs based on feedback from the movements of the astronaut.

Volunteers wearing constrictive garments designed to mimic the stiffness of traditional spacesuits were able to stand stably with less effort when assisted by the robot.

“It feels kind of like an extra force moving with you,” says Erik Ballesteros, a PhD student in mechanical engineering at MIT.

“Imagine wearing a backpack and someone grabs the top and sort of pulls you up. Over time, it becomes sort of natural.”

A photograph of 3 men inside a lab. Left is a young man in a grey polo shirt and black pants. Centre is an older man wearing  a white shirt and black dress pants. Right is a young man wearing a suit of white panels and straps. 2 metallic robot arms are protruding from something strapped behind his back.
Pictured, from left, is Sang-Yoep Lee, Harry Asada, and Erik Ballesteros (wearing the SuperLimb system). Jennifer Chu

The MIT team envisions that SuperLimbs could prove useful during NASA’s upcoming Artemis III mission.

Artemis plans to send astronauts back to the Moon where they will endeavour to build the first permanent Moon base – a physically demanding task that will require multiple extended extravehicular activities (EVAs).

“During the Apollo era, when astronauts would fall, 80% of the time it was when they were doing excavation or some sort of job with a tool,” says Ballesteros.

“The Artemis missions will really focus on construction and excavation, so the risk of falling is much higher. We think that SuperLimbs can help them recover so they can be more productive and extend their EVAs.”

Asada, Ballesteros and colleagues are presenting their design and study this week at the Institute of Electrical and Electronics Engineers (IEEE) International Conference on Robotics and Automation (ICRA2024) in Yokohama, Japan.

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