Robots Could Build Massive Metamaterial Radars in Orbit

• NASA is funding research into a proposal to build massive radar antennas in orbit using robotic assembly and metamaterials.
• The system aims to overcome current size constraints of space-based antennas, which are limited by rocket fairing capacity.
• The project is currently in the NASA Innovative Advanced Concepts (NIAC) Phase I stage, designed to explore high-risk, high-reward concepts.

The Problem: Space Debris

• Earth-based systems like the Space Fence can detect debris down to 10 cm, but smaller objects remain largely untracked.
• Small debris traveling at 17,000 mph poses a significant collision risk to satellites and spacecraft.
• Current space-based antennas are restricted by the 'tyranny of the fairing,' limiting their diameter even when deployable.

The Proposed Solution

• Dr. David Smith of Duke University proposes building massive, modular antenna structures directly in space.
• The antenna would be composed of electromagnetic metamaterial 'unit cells' that act as both individual antennas and a collective programmable lens.
• Assembly would be performed by robotic systems, such as NASA's Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS).
• The ARMADAS system functions like an inchworm-crawling robot that snaps modular blocks ('voxels') together in 3D.

Key Benefits and Remaining Questions

• The 3D structure allows for omnidirectional radar sweeps without the need for mechanical moving parts, which are prone to failure in space.
• Because the structure is modular, it could theoretically be built to any size necessary to detect small debris.
• Practical challenges, such as the vulnerability of the structure to impacts from the very debris it is meant to track, remain to be addressed in later research phases.