NASA’s new dark energy space telescope can also detect killer asteroids

The Nancy Grace Roman Space Telescope was not originally designed for planetary defense, but its hardware, particularly its 300-megapixel infrared camera and wide field of view, makes it capable of detecting asteroids as small as 60 feet. This dual-use functionality emerges from its primary mission to study dark energy and galaxies, where it will inevitably observe objects within our solar system. The telescope’s ability to cover 100 times the area of Hubble in a single frame means it can scan vast regions of space quickly, increasing the odds of spotting near-Earth asteroids that ground-based telescopes might miss due to limited sky coverage or atmospheric interference.

Adapting the Roman telescope for asteroid detection requires software changes to its data processing pipeline. Currently, the telescope’s software discards streaks caused by cosmic rays, glitches, or asteroids as noise to maintain clarity for deep-space observations. To repurpose it for planetary defense, astronomers will need to modify the pipeline to flag and analyze these streaks, distinguishing asteroids from other artifacts. This adjustment is non-trivial but feasible, as it leverages existing data without requiring new hardware. The cost lies in the development and validation of new algorithms, as well as the computational resources needed to process and store additional data.

The Roman telescope’s strength in asteroid detection lies in its ability to complement other observatories, such as the James Webb Space Telescope (JWST). While JWST can provide detailed observations of individual asteroids, its narrow field of view limits its capacity for broad surveys. Roman, by contrast, can quickly scan large swaths of the sky, identifying potential threats that JWST or ground-based telescopes can then investigate further. This synergy could improve the efficiency of planetary defense efforts, but it also introduces dependencies: Roman’s effectiveness relies on follow-up observations from other instruments to confirm trajectories and assess risks.

The telescope’s asteroid detection capabilities are not a replacement for dedicated planetary defense systems. It is optimized for deep-space observations, meaning its ability to track fast-moving or dim asteroids may be limited compared to telescopes specifically designed for near-Earth object (NEO) detection. Additionally, its infrared sensors are tuned for distant galaxies, not solar system objects, which could reduce sensitivity to certain asteroid compositions. While it can detect smaller asteroids (down to 60 feet), the majority of undetected threats, such as those 165 feet or larger, remain beyond its primary focus. This underscores the need for continued investment in specialized NEO detection systems, even as Roman provides a valuable supplementary tool.