Caltech's ASTRA robot builds a structure in space, solo

Building things in space has always needed a person in a spacesuit. On Nov. 10, Caltech and the Pentagon's research arm DARPA said that changed. A robot called ASTRA, launched in March 2026, did the work. It used loose struts and joints to assemble part of an antenna truss. The whole time, it was orbiting Earth. No astronaut touched it. It's the first time anyone has built a structure in space on its own.

This matters beyond one antenna. Rockets can only carry things as big as their nose cone allows. That caps how large a telescope, solar array, or space station module can be. If robots can build structures piece by piece once they're already in orbit, that size limit mostly disappears. Caltech professor Sergio Pellegrino led the project. He says the technology could eventually let scientists build huge telescopes, communications antennas, and solar power stations in orbit.

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How much bigger can this get? ASTRA built one small antenna reflector, a little over 4 feet across, using pre-built pieces it carried into orbit. Scaling that up to a space station-sized structure means solving harder problems. There are more parts and longer build times. Components have to survive months or years of assembly with zero room for error.