Falling On The Moon? MIT’s ‘SuperLimbs’ Could Help Astronauts Get Back Up

Astronauts will soon be getting a “leg up” on moonwalks thanks to engineers from the Massachusetts Institute of Technology. Professor Harry Asada and his team at MIT are developing a pair of wearable robotic limbs dubbed “SuperLimbs” to help astronauts safely and efficiently recover from falls on the Moon. The concept is simple: when an astronaut falls, the SuperLimbs extend from a backpack and lift them back to their feet, conserving energy for other crucial tasks.

Astronauts struggle with lunar locomotion due to the unique conditions on the Moon.

“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. Furthermore, wearing a spacesuit is a significant burden and can constrict their movements,” says Asada, professor of mechanical engineering at MIT. “We want to provide a safe way for astronauts to get back on their feet if they fall.” 

SuperLimbs, a system of wearable robotic limbs built by MIT engineers, is designed to physically support an astronaut and lift them back on their feet after a fall, helping them conserve energy for other essential tasks
SuperLimbs, a system of wearable robotic limbs built by MIT engineers, is designed to physically support an astronaut and lift them back on their feet after a fall, helping them conserve energy for other essential tasks. Pictured, from left, is Sang-Yoep Lee, Harry Asada, and Erik Ballesteros. (CREDIT: Jennifer Chu)

The SuperLimbs project aims to address these challenges by providing a helping hand (or in this case, a helping limb) to fallen astronauts. The robotic limbs are designed to extend from a backpack that also houses the astronaut’s life support system, along with the necessary controllers and motors.

To put their concept to the test, MIT researchers built a physical prototype and a control system that responds to the astronaut’s movements. They even asked volunteers to wear a constrictive garment similar to a spacesuit to simulate the real-world conditions astronauts face. When assisted by SuperLimbs, the volunteers were able to get up from sitting or lying positions with less effort compared to when they had to recover on their own.

The potential applications for SuperLimbs are particularly relevant in light of NASA’s upcoming Artemis mission, which plans to send astronauts back to the Moon for the first time in over half a century. Unlike the largely exploratory Apollo missions, Artemis astronauts will be tasked with building the first permanent Moon base — a physically demanding endeavor that will require multiple extended extravehicular activities (EVAs).

“During the Apollo era, when astronauts would fall, 80 percent of the time it was when they were doing excavation or some sort of job with a tool,” explains Erik Ballesteros, team member and MIT doctoral student. “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.”

The team’s design builds upon Asada’s previous work on SuperLimbs, which he first developed about a decade ago. Since then, the concept has been adapted for various applications, from assisting workers in aircraft manufacturing and construction to aiding ship builders.

To refine their design for astronauts, researchers first studied how humans naturally recover from falls. They mapped the movements of volunteers as they stood up from various positions and found a common sequence of motions, or “waypoints,” that most people follow. This data was then used to develop a controller that generates a trajectory for the robotic limbs to support and lift the astronaut.

When the controller was applied to a heavy, fixed robotic arm attached to a backpack, volunteers wearing the bulky suit were able to stand stably with much less effort compared to when they tried to stand alone.

“It feels kind of like an extra force moving with you,” says Ballesteros, who also tried out the suit and arm assist. “Imagine wearing a backpack and someone grabs the top and sort of pulls you up. Over time, it becomes sort of natural.”

The next steps for the SuperLimbs project involve building out the full system at NASA’s Jet Propulsion Laboratory, where Ballesteros plans to optimize the design using advanced, lightweight materials. The ultimate goal is to pair the robotic limbs with astronaut suits and test them in low-gravity simulators, paving the way for their use on future missions to the Moon and Mars.

“Wearing a spacesuit can be a physical burden,” concludes Asada. “Robotic systems can help ease that burden, and help astronauts be more productive during their missions.”

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