ASTRA: a robot builds the first structure on its own in orbit
· BehindLines newsroom
A robot designed at Caltech has assembled part of a structure in orbit without any astronaut's help. In a release dated 5 November and picked up on 9 November by ScienceDaily, the California institute presents the experiment as the first autonomous construction in space. Project leader Sergio Pellegrino says no structure had ever before been put together in space without human hands.
The experiment
The demonstration is called ASTRA (Autonomous In-Space Tensioned Reflector Assembly). It aims to build a reflector antenna 1.4 metres across, made of composite-fibre tubes, aluminium connectors and a reflective Kapton surface. Funding comes from DARPA's NOM4D programme, begun in 2022. The project is in its third phase, the in-orbit test, after design and validation stages on the ground.
The module, about one cubic metre in size, lifted off on 30 March 2026 from Vandenberg aboard Vigoride 7, a vehicle from the company Momentus that carried ten payloads, on SpaceX's Transporter-16 mission. It held two pre-built truss bays, a robotic arm and motorised part dispensers. On commands from the ground, the robot deployed the two bays and then built a third.
A partial result
A complete antenna would need 11 bays. According to Caltech, the team does not expect to finish them all before the mission ends in December. It nonetheless considers the proof made: the method works in orbit and could scale to very large structures. DARPA programme manager Andrew Detor speaks of structures hundreds of metres or even kilometres across.
Operators had only seven or eight communication windows a day, of about fifteen minutes each. A spare unit kept in the laboratory was used to reproduce incidents and test fixes before sending them up. The reflective film, developed with the University of Pennsylvania under Igor Bargatin, needs less tension than a knitted metal mesh, which can make the whole assembly lighter.
What it changes
Today the size of space instruments is limited by the rocket fairing. Assembling in orbit parts shipped in compact packages could serve telescopes, radio antennas or solar arrays, including the Space Solar Power Project that Pellegrino co-directs. The design must first be simplified and refined. A second project, from the University of Illinois Urbana-Champaign, is due to test the hardening of carbon tubes on a module of the International Space Station.