A robot has built part of a structure in orbit without any help from astronauts, in what researchers say is the first autonomous construction ever carried out in space.
The robotic truss builder was developed by researchers at the California Institute of Technology (Caltech) and funded by the US Defense Advanced Research Projects Agency (DARPA). It uses a robotic arm to pick up composite fibre tubes and aluminium joints from onboard dispensers and join them into identical repeating sections, known as bays, of a perimeter truss.
The system, called the Autonomous In-Space Tensioned Reflector Assembly (ASTRA), spent six months in orbit working on a reflector antenna 1.4 metres across, made from composite fibre tubes, aluminium joints and a Kapton reflective surface. It launched on 30 March 2026 from Vandenberg Space Force Base in California, carried into low Earth orbit aboard Momentus Inc.’s Vigoride 7 vehicle on a SpaceX Transporter-16 mission.
Two bays of the truss travelled to orbit prebuilt. The robot then assembled a third bay itself, with the result photographed by one of the payload’s 11 cameras. “This is the first time that a structure has been autonomously constructed in space,” said Sergio Pellegrino, the Caltech professor who leads the ASTRA team.
Time limits meant the team could only build the initial section, and the full 11-bay antenna is unlikely to be completed before the mission ends in December. But the researchers say the demonstration proves the approach works and can be scaled up.
The work is part of DARPA’s Novel Orbital and Moon Manufacturing, Materials, and Mass-efficient Design (NOM4D) programme, launched in 2022 with the long-term goal of manufacturing very large structures directly in space. “By ‘very large,’ I mean hundreds of metres or kilometres in scale. Nothing approaching that scale can be achieved today,” said Andrew Detor, DARPA’s programme manager for NOM4D.
Until now, large structures have either been folded up for launch and unfurled in orbit, or pieced together by astronauts over a series of missions. Building them in place would remove the size limit set by rocket fairings. Such structures could serve as mirrors for powerful space telescopes, the apertures of large radio antennas, or very large solar arrays beaming power to Earth.
Operating the robot was far from straightforward. The ground team could only communicate with it during about seven or eight short windows of roughly 15 minutes each day, and repeatedly had to work around unexpected problems by testing fixes on a flight spare kept in Pellegrino’s laboratory at Caltech.
Sources: Phys.org — “Robot successfully builds space structure in first autonomous construction demo” (6 November 2026), https://phys.org/news/2026-11-robot-successfully-space-autonomous-demo.html; ScienceDaily, https://sciencedaily.com/releases/2026/11/261108233043.htm
