Caltech-Led ASTRA Robot Builds Part of an Antenna Structure in Orbit

On Nov. 5, 2026, Caltech professor Sergio Pellegrino said the ASTRA demonstration achieved the first autonomous construction of a structure in space. The payload assembled part of a truss-based antenna, rather than the full structure.

Key details

• ASTRA stands for Autonomous In-Space Tensioned Reflector Assembly.
• Caltech led the demonstration, with funding from DARPA.
• The structure measured 1.4 meters (4.5 feet) across.
• The robot used Kapton film, composite fiber tubes and aluminum joints.
• ASTRA launched on Momentus’s Vigoride 7 space tug as part of SpaceX’s Transporter-16 rideshare mission on March 30, 2026.
• The payload carried two prebuilt truss sections and equipment for additional construction. The team did not complete the full truss within the time available.
• Engineers had communication windows totaling about 15 minutes per day to send commands and monitor the robot.

ASTRA assembled part of a truss-based antenna measuring 1.4 meters across.

Why it matters

DARPA’s NOM4D program is developing methods to build large structures in space, with a stated goal of designs hundreds of meters or kilometers in scale. ASTRA’s demonstration put autonomous assembly to work on part of a structure in orbit.