Plate Nº 33 · recorded November 13, 2026
Space & AstronomyReported finding
DARPA Program Assembles First Structure in Orbit, Months Early
DARPA's NOM4D program assembled a truss structure in orbit with a gantry robot, 15 months after switching from lab tests to a space demo — a first step toward kilometer-scale construction.
By Elena Vasquez4 min read748 words
In brief
- DARPA's NOM4D program demonstrated automated in-space assembly for the first time.
- SpaceX launched Caltech's NOM4D payload in March 2026, 15 months after the February 2025 decision to move testing on-orbit.
- A gantry robot built a truss structure and applied a reflective mesh mimicking a space antenna.
- The program targets structures hundreds of meters to kilometers in scale.
- A follow-up ISS test by the University of Illinois Urbana-Champaign will demonstrate composite material processing using monomer resin.
A DARPA program has assembled a structure in orbit automatically, for the first time — and it got there 15 months after the decision to skip lab work and go straight to space.
The demonstration belongs to NOM4D, short for Novel Orbital and Moon Manufacturing, Materials and Mass-efficient Design. A gantry robot — a machine that moves in straight lines along x, y and z axes — built a truss structure from individual components supplied by Caltech. As it assembled the parts, it also applied a thin reflective mesh that mimics the surface of a space-based antenna.
"NOM4D's objective is to enable efficient, scalable construction of very large structures in space," said Andrew Detor, the program's manager. "By 'very large,' I mean hundreds of meters or kilometers in scale. Nothing approaching that scale can be achieved today."
Why build in space at all?
The logic comes down to physics. Rocket fairings — the nose cones that carry payloads — are simply too small for the large structures we want in space, and the rocket equation, which governs how much mass a launcher can carry, doesn't bend to wishful thinking.
The James Webb Space Telescope worked around this with an ingenious folding design that unfolded in orbit. But folding isn't practical for everything. Sending small components up and assembling them on site is the more feasible route, and that's exactly what NOM4D just proved can be done.
The approach is deliberately simple. Detor compares it to Tinkertoys or K'nex: individual truss members joined at nodes, one section at a time.
"There are no complicated robotics or advanced algorithms; it's just solid engineering from the Caltech team to combine operations in a way that scales," Detor said. Each section is built piece by piece, the mesh is attached, and finished sections are deployed as they're complete.
How did it happen so fast?
The timeline surprised even the program's own staff. In February 2025, DARPA scrapped plans for a third phase of laboratory tests and switched to on-orbit testing instead. SpaceX launched Caltech's NOM4D payload in March 2026.
"Caltech and the University of Illinois Urbana-Champaign have demonstrated tremendous advances in the first two phases and have now partnered in Phase 3 with space-launch companies to conduct in-space testing of their novel assembly processes and materials," Detor said at the time.
"Originally, Phase 3 was going to be about making things more precisely in the lab than we did in Phase 2," he explained. "But we said, 'You know, the maturity is there, and there would be more impact if we took the capabilities we have now and actually go demonstrate them in space.'"
That speed is the point. "It's the speed and the scale that made this a DARPA project," Detor said. "Operating in space is much harder than operating on the ground — there's virtually no margin to address issues that may arise."
What comes next?
One more test is on the schedule. A University of Illinois Urbana-Champaign team will launch a project to the International Space Station to demonstrate composite material processing — building a high-strength structure in orbit from a monomer resin using an energy-efficient heating method. It's similar to how resins are used in carbon fiber reinforced polymer manufacturing for aerospace components.
What could these structures become?
The candidate applications read like a wish list from 1970s space advocacy. They include:
- Large space depots, habitats, solar arrays and radio antennas
- Low Earth orbit and lunar orbit transfer stations, possibly hybrids of premade modules and NOM4D-built frameworks
- Reinforced lunar lava tubes turned into habitats, shielded naturally from hazards
- Liquid mirror telescopes built in lunar craters
- NASA's Lunar Crater Radio Telescope concept on the lunar far side, isolated from Earth's radio pollution
Gerard K. O'Neill's vision of rotating space stations housing thousands — laid out 50 years ago in "The High Frontier" — remains distant. But Detor frames the recent milestone as a foundation, not a finish line.
"In a future space economy, we're going to need large things," he said. "Those things require size, and NOM4D gives us a path to accelerate creation of new capabilities."
"The NOM4D Caltech demonstration is not an endpoint; it's a beginning," Detor said. "Now that we've demonstrated a process that can scale to large structures, what do we go make?"
If the ISS composite test succeeds, that question stops being rhetorical.
via phys.org/rss-feed/ (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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