Self-assembling robotic structures could be NASA’s next step in space construction

There’s bad news if you’re considering moving to the moon or Mars: housing is hard to come by. As always, NASA is thinking ahead and has just demonstrated a self-assembling robotic structure that might just be crucial to moving off-planet.

A paper published today in Science Robotics describes the creation and testing of what NASA Ames Research Center calls “self-reprogrammable mechanical metamaterials,” a highly precise description of something that can build itself. The paper from NASA Ames Research Center describes the creation and testing of an artificial building that can construct itself. ARMADAS is an acronym for the Automated Reconfigurable Mission Adaptive Digital Assembly Systems, or ARMADAS for short.

Lead author Christine Gregg told TechCrunch that this type of construction technology could be used in a variety of very general applications. Our approach’s robust autonomy and lightweight structures are especially suited to austere environments, such as the lunar surface and space. As well as construction of communication towers and shelters on the lunar surface, astronauts will also need on-orbit structures like booms and antennae.”

A self-building structure relies on a clever synergy between cuboctahedral frames called voxels and two types of robots that assemble them.

Apparently inspired by the kinesin transport molecules in our own biology, one robot walks on two legs while carrying a voxel in a backpack. After that’s installed, a worm-like fastening robot slithers over and tightens the reversible attachment points. They don’t require powerful sensors and don’t require high precision because of the way they work.

Most of the images in this post show a pair of walkers and a fastener worm. A transport walker hands off a voxel to a placement walker, and a fastener bot lurks below, waiting to lock the frame in place.

Another robot waits below to attach a structural element to the lattice while two robots exchange a structural element.

Due to their shape, the pieces can be attached at various angles while maintaining good structural strength. It’s unlikely you’d want to store rocks on top of a dome made out of these things, but they’d be perfect for making a dwelling after adding insulation and sealant.

“We think this type of construction is particularly suited to long duration and/or very large infrastructure, including habitats, instrumentation or any other infrastructure on orbit or the surface of the moon (utility towers, vehicle landing facilities),” said co-author Kenneth Cheung. “For us, the structures and all of the robotic systems are resources that can be optimized over space and time. It looks like there will always be situations where the optimal thing is to leave just structure in place (and perhaps visit to inspect it with a robot periodically), so we started with that.”

Gregg noted that pieces could also be constructed on-site:

Materials and manufacturing processes can be used to make voxels. In the future, we would like to make voxels from materials we find on the moon or other planets.”

These videos show the robots at work at high speeds, but speed is not necessarily of the essence when it comes to building stuff in space or on another planet’s surface.

“Our robots are capable of working faster than shown in this paper, but we didn’t see it as crucial to our primary goals. Using more robots is fundamentally the key to speeding up the system, said Cheung. A strategy for scalability (of speed and size) is to push the complexity of scale onto algorithms, for planning and scheduling, detecting faults, and performing repairs.

In 4.2 days, the lab’s robots assembled 256 voxels into a passable shelter structure using 256 voxels. Here’s what it looked like at the beginning (again, not real-time):

With time to spare, they could have built a dozen such structures twice the size on Mars or the moon if we’d sent them ahead of a crew a year in advance. That’s beyond the scope of the paper published today, but it’s an obvious next step if they attach the necessary plating afterwards.

Although the robots have tethers running power to them, they are being designed with battery operation or on-site power in mind. Currently, the fastener bots are battery-powered, and the researchers are considering methods for charging them while they are in use.

“We envision robots being recharged autonomously at power stations, or even wirelessly. It is also possible to route power through the structure itself, which could be useful for outfitting the structure and powering robots,” Gregg said.

The ARMADAS building is shown as a concept illustration under the supervision of astronauts

Image Credits: NASA

There have already been versions of the robot that have flown in space and worked in microgravity. Furthermore, there should be no problem with them working in gravity conditions other than Earth’s, such as those on the moon. As such, we are just getting started – much like revealing the existence of nails and 2x4s. Visit NASA’s news post for more information on the potential and concept illustrations.

The next versions of our laboratory robots will be faster and more reliable, based on the lessons we’ve learned from the first versions. Gregg is interested in understanding how different types of building blocks can be integrated into the structures to provide functional outfitting.

A crude shelter might take two walkers four days to build, but something 10 times bigger might take 100 times longer. Furthermore, research will continue on structures that employ swarms of robots, not just a handful. It takes many hands – especially robotic ones – to accomplish a task.