A robotic system in low Earth orbit built part of a structure without human assistance.
Researchers at the California Institute of Technology developed the Autonomous In-Space Tensioned Reflector Assembly payload, known as ASTRA. Funding came from the Defense Advanced Research Projects Agency.
“This is the first time that a structure has been autonomously constructed in space,” said Sergio Pellegrino, the Joyce and Krent Kresa Professor of Aerospace and Civil Engineering at Caltech and a senior research scientist at JPL.
Orbital Launch Details
The hardware launched on March 30, 2026. A SpaceX Transporter-16 mission carried it from Vandenberg Space Force Base.
Momentus Inc.’s Vigoride 7 orbital vehicle carried the payload. That vehicle transported 10 separate payloads into low Earth orbit.
ASTRA fit into a volume of about one cubic meter. Inside were motorized dispensers and a gantry robot moving along three linear axes to pick composite fiber tubes and aluminum joints.
The machine deployed two pre-built bays during the demonstration. It then constructed a third bay in orbit.
The system attached a perforated Kapton polymer film as each section took shape. The University of Pennsylvania developed that film to serve as a reflective surface.
NOM4D Program Goals
The project is part of DARPA’s Novel Orbital and Moon Manufacturing, Materials and Mass-efficient Design program. That program was established in 2022 to investigate technologies that could eventually ferry raw materials from Earth for in-orbit manufacturing.
“NOM4D’s objective is to enable efficient, scalable construction of very large structures in space,” said Andrew Detor, DARPA program manager for NOM4D.
“By ‘very large,’ I mean hundreds of meters or kilometers in scale. Nothing approaching that scale can be achieved today,” said Andrew Detor.
Traditional space hardware must fold inside a rocket fairing or undergo manual assembly by astronauts. Both methods impose strict limits on finished dimensions.
Autonomous assembly offers an alternative. It allows compact raw materials to be shipped up and built out on station.
Ground Troubleshooting Work
Engineering teams managed the orbital hardware by monitoring photographs transmitted from space. They replicated difficulties on a flight spare maintained at Caltech’s laboratory.
Differences between laboratory conditions and the space environment brought unexpected challenges.
The mission is scheduled to conclude in December 2026. Researchers plan to apply the data toward future applications in communications, astronomy, and space-based solar power.
“That’s basically the reason you do proof-of-concept testing,” Pellegrino said.
Earlier coverage: Caltech's ASTRA Robot Successfully Builds Structure in Orbit
