A robot built by a team at Caltech has autonomously assembled a structure in orbit for the first time, with no direct human intervention during the build. The machine, named Astra, constructed one section of a 1.4-meter reflector antenna while circling Earth, a step toward building large space hardware directly in orbit rather than launching it whole.
Astra lifted off on March 30 from Vandenberg Space Force Base in California, aboard the Vigoride-7 spacecraft, and ran its mission for roughly six months in low Earth orbit. Its robotic arm picks parts from motorized dispensers and joins them into lattice modules. The structure is built from composite tubes, aluminum joints and Kapton reflective film, materials chosen to be light enough to launch and strong enough to hold their shape once deployed.
The job was made harder by communication limits. The spacecraft had only seven or eight short contact windows of about fifteen minutes each per day, so the team relied on a ground duplicate of the robot to test fixes and software changes before sending them up. The complete antenna was designed to use eleven modules, but the full assembly was not finished, and the mission is scheduled to end in December.
Astra is part of a Defense Advanced Research Projects Agency program known as Nom4d, which aims to develop methods for building large structures in space. Engineers see possible uses in space telescopes, radio antennas and large solar power panels, all of which are hard to fit inside a rocket fairing. A robot that can assemble such hardware on orbit could, in principle, make bigger instruments practical without requiring a bigger launch vehicle.