Robots could build giant metamaterial radars in space to track hidden threats

Space is becoming increasingly crowded, and tracking the objects orbiting Earth is becoming a harder engineering problem. NASA is now funding a particularly unconventional idea that could eventually help build enormous radar antennas in space using robots and modular metamaterials. The concept, led by Duke University electrical and computer engineering professor David Smith, was selected for a 2026 NASA Innovative Advanced Concepts (NIAC) Phase I study. The project is called Robotically Assembled Electromagnetic Metamaterials for Long-Range Space Situational Awareness. This is still a research concept and not an operational space radar. The Phase I work is intended to determine whether the underlying approach could eventually become practical. Why build a radar in space? Space surveillance networks already use powerful ground-based radars to track objects in orbit. NASA says systems such as the upgraded Space Fence can track objects down to roughly four inches (about 10 cm) in low Earth orbit. But tracking smaller objects, or monitoring spacecraft at much greater distances, becomes considerably more difficult. The basic physics creates the problem. The farther away a target is, the larger the radar’s effective aperture needs to be for a given detection performance. For objects beyond low Earth orbit, NASA says the size requirements of ground-based arrays can become impractical. Putting the radar closer to the objects could help. But conventional space antennas have an obvious limitation. They have to survive launch and fit inside a rocket’s available volume. That is where the unusual part begins. What if the antenna was built after launch? Instead of launching one enormous antenna, Smith’s concept would send its components into space and have robots assemble them there. NASA already has relevant technology under development through ARMADAS, or Automated Reconfigurable Mission Adaptive Digital Assembly Systems. The project uses relatively simple robots to assemble standardized structural building blocks called voxels. In a NASA demonstration, three robots autonomously assembled hundreds of these blocks into a structure roughly the size of a shed. The robots operated in an inchworm-like fashion, transporting, positioning, and fastening the modules. The idea is therefore less like sending a giant antenna into orbit and more like sending a construction kit. The building blocks would not simply be pieces of metal. Smith specializes in electromagnetic metamaterials. These are artificially structured materials whose geometry can be engineered to interact with electromagnetic waves in unusual ways. His Duke group famously demonstrated a microwave-frequency metamaterial “invisibility cloak” in 2006, showing that engineered structures could manipulate electromagnetic waves in ways conventional materials could not easily achieve. For the NASA concept, metamaterials could effectively become the building blocks of a huge electromagnetic aperture. Rather than treating the antenna as one enormous conventional structure, researchers could assemble many small electromagnetic elements into a much larger system. NASA says the project will investigate metamaterial designs using numerical modeling, while incorporating the practical constraints of robotic assembly demonstrated by ARMADAS. Why make it enormous? For radar and other electromagnetic sensing systems, a larger aperture can provide advantages in resolution and sensitivity. NASA notes that increasing aperture size can improve the performance of beam-steering, radar, and observation missions. That could potentially make an assembled-in-space system useful for tracking increasingly distant or difficult-to-detect objects. And the concept isn’t necessarily limited to debris tracking. NASA says the same design principles could eventually apply to large-aperture instruments used for Earth observation and deep-space communications. The hard part is making it survive The concept also comes with major unanswered questions. A huge structure assembled from thousands or millions of modules would have to remain mechanically and electrically reliable in orbit. Individual components could be damaged by micrometeoroids or orbital debris, while the structure would have to tolerate thermal cycling and the harsh space environment. An especially challenging aspect is that the radar would have to operate in the same debris-filled environment it is designed to monitor. A large modular structure could potentially be struck by the same kind of high-speed debris it is intended to track, raising questions about how individual damaged metamaterial elements would be replaced and whether a localized failure could affect the wider antenna. These are not limitations NASA identifies in its Phase I description, but they illustrate the practical questions that would have to be answered if the concept progresses beyond the study stage. NASA’s ARMADAS work is already exploring autonomous construction and reconfiguration, but its demonstrated structures are laboratory-scale compared with the giant apertures envisioned for advanced space sensing. That is precisely why the new project is interesting. It combines three technologies that have largely developed separately. Metamaterials, autonomous robotic construction, and large space structures. If the concept works, the biggest breakthrough may not simply be a better radar. It could be a new way of building enormous infrastructure in orbit without having to launch that infrastructure as a single enormous machine. Get the latest in engineering, tech, space & science - delivered daily to your inbox.Kaif Shaikh is a journalist and writer passionate about turning complex information into clear, impactful stories. His writing covers technology, sustainability, geopolitics, and occasionally fiction. A graduate in Journalism and Mass Communication, his work has appeared in the Times of India and beyond. After a near-fatal experience, Kaif began seeing both stories and silences differently. Outside work, he juggles far too many projects and passions, but always makes time to read, reflect, and hold onto the thread of wonder.