When astronauts begin to construct a permanent base on the moon, as NASA hopes to do in the coming years, they will want assistance. Robots might potentially handle the hard lifting by installing wires, erecting communications towers, and constructing habitats.
However, if each robot is programmed to perform a specific action or task, a lunar colony may be overrun by a zoo of machines, each with its own set of parts and protocols.
To circumvent a bot bottleneck, an MIT team is developing a kit of universal robotic parts that an astronaut could easily mix and match to quickly create different robot “species” to accommodate diverse moon missions. After completing a mission, a robot can be disassembled and its parts repurposed to build a new robot to do a different task.
The team calls the system WORMS, for the Walking Oligomeric Robotic Mobility System. The system’s components include worm-inspired robotic limbs that can be quickly snapped onto a base and work together to form a walking robot.
Parts can be configured to construct enormous “pack” bots capable of transporting hefty solar panels up a hill, for example, depending on the goal. The same components might be reassembled into six-legged spider bots capable of drilling for frozen water in lava tubes.
“You could imagine a shed on the moon with shelves of worms,” says team leader George Lordos, a PhD candidate and graduate instructor in MIT’s Department of Aeronautics and Astronautics (AeroAstro), in reference to the independent, articulated robots that carry their own motors, sensors, computer, and battery. “Astronauts could go into the shed, pick the worms they need, along with the right shoes, body, sensors and tools, and they could snap everything together, then disassemble it to make a new one. The design is flexible, sustainable, and cost-effective.”
There are many buzz words that are used to describe effective systems for future space exploration: modular, reconfigurable, adaptable, flexible, cross-cutting, et cetera. The MIT WORMS concept incorporates all these qualities and more.
Kevin Kempton
Lordos’ team has built and demonstrated a six-legged WORMS robot. Last week, they presented their results at IEEE’s Aerospace Conference, where they also received the conference’s Best Paper Award.
MIT team members include Michael J. Brown, Kir Latyshev, Aileen Liao, Sharmi Shah, Cesar Meza, Brooke Bensche, Cynthia Cao, Yang Chen, Alex S. Miller, Aditya Mehrotra, Jacob Rodriguez, Anna Mokkapati, Tomas Cantu, Katherina Sapozhnikov, Jessica Rutledge, David Trumper, Sangbae Kim, Olivier de Weck, Jeffrey Hoffman, along with Aleks Siemenn, Cormac O’Neill, Diego Rivero, Fiona Lin, Hanfei Cui, Isabella Golemme, John Zhang, Jolie Bercow, Prajwal Mahesh, Stephanie Howe, and Zeyad Al Awwad, as well as Chiara Rissola of Carnegie Mellon University and Wendell Chun of the University of Denver.
Animal instincts
WORMS was conceived in 2022 as an answer to NASA’s Breakthrough, Innovative and Game-changing (BIG) Idea Challenge an annual competition for university students to design, develop, and demonstrate a game-changing idea.
In 2022, NASA challenged students to develop robotic systems that can move across extreme terrain, without the use of wheels.
A team from MIT’s Space Resources Workshop accepted the challenge, aiming primarily for a lunar robot design capable of navigating the severe terrain of the moon’s South Pole, which is characterized by thick, fluffy dust, steep, rocky slopes, and deep lava tunnels. The environment also has “permanently shadowed” areas that may hold frozen water, which, if accessible, would be critical for astronaut survival.
Animals inspired the kids as they considered how to navigate the moon’s polar region. During their early brainstorming, they discovered that particular creatures may theoretically be suited to specific missions: A spider could descend into a lava tunnel, a herd of elephants might carry heavy equipment while supporting each other down a steep slope, and a goat harnessed to an ox could help lead the larger animal up the side of a hill while transporting a solar panel array.
“As we were thinking of these animal inspirations, we realized that one of the simplest animals, the worm, makes similar movements as an arm, or a leg, or a backbone, or a tail,” says deputy team leader and AeroAstro graduate student Michael Brown. “And then the lightbulb went off: We could build all these animal-inspired robots using worm-like appendages.’”
Snap on, snap off
Lordos, who is of Greek descent, helped coin WORMS, and chose the letter “O” to stand for “oligomeric,” which in Greek signifies “a few parts.”
“Our idea was that, with just a few parts, combined in different ways, you could mix and match and get all these different robots,” says AeroAstro undergraduate Brooke Bensche.
The appendage, or worm, can be attached to a body, or chassis, using a “universal interface block” that snaps the two components together using a twist-and-lock mechanism. The parts can be disconnected with a small tool that releases the block’s spring-loaded pins.
Appendages and bodies may also snap into accessories like a “shoe,” which the researchers designed in the shape of a wok, and a LiDAR system, which can map the environment to assist a robot in navigation.
“In future iterations we hope to add more snap-on sensors and tools, such as winches, balance sensors, and drills,” says AeroAstro undergraduate Jacob Rodriguez.
The team developed software that can be tailored to coordinate multiple appendages. As a proof of concept, the team built a six-legged robot about the size of a go-cart. They demonstrated in the lab that, once completed, the robot’s autonomous limbs could walk across level ground.
The researchers also demonstrated how rapidly they could assemble and disassemble the robot in the field, on a desert site in California.
In its first generation, each WORMS appendage measures about 1 meter long and weighs about 20 pounds. Each limb would weigh roughly 3 pounds under the moon’s gravity, which is about one-sixth that of Earth’s, which an astronaut could easily handle to create or disassemble a robot in the field.
The team has planned the specifications for a larger generation with longer and slightly heavier appendages. These larger components might be snapped together to create “pack” bots capable of transporting enormous cargoes.
“There are many buzz words that are used to describe effective systems for future space exploration: modular, reconfigurable, adaptable, flexible, cross-cutting, et cetera,” says Kevin Kempton, an engineer at NASA’s Langley Research Center, who served as a judge for the 2022 BIG Idea Challenge. “The MIT WORMS concept incorporates all these qualities and more.”
NASA, MIT, the Massachusetts Space Grant, the National Science Foundation, and the Fannie and John Hertz Foundation supported this research, in part.
