Caltech robot builds a truss section in orbit without astronauts
DARPA’s NOM4D ASTRA demo assembled a third bay of a planned 1.4-meter reflector antenna in space.
A Caltech-built robotic truss builder has assembled a structure in space without astronauts for the first time, the university said in a Nov. 5 news release about its DARPA-funded ASTRA demonstration.
ASTRA, short for Autonomous In-Space Tensioned Reflector Assembly, is part of DARPA’s NOM4D program to manufacture large structures in orbit. An onboard manipulator picks struts and joints from dispensers and repeats the same sequence to build identical truss “bays,” like a high-tech construction toy, according to Caltech.
The payload launched March 30, 2026, from Vandenberg Space Force Base aboard Momentus’ Vigoride 7 on a SpaceX rideshare. It carried two prebuilt bays plus parts for more; the team then assembled a third bay in orbit while troubleshooting with a twin on the ground during short daily radio windows.
The goal is a 1.4-meter reflector antenna made of composite tubes, aluminum joints and a Kapton surface—useful someday for telescopes, radio antennas or space solar power—but time limits mean the full 11-bay build is unlikely before the mission ends in December, Caltech said.
Source: Caltech, Nov. 5, 2026