Arecibo's S-Band radar was extensively used in the tracking of near-Earth asteroids, which was termed "planetary defense" by NASA. It was nearly 20x more sensit

Arecibo's S-Band radar was extensively used in the tracking of near-Earth asteroids, which was termed "planetary defense" by NASA. It was nearly 20x more sensitive than any other telescope capable of radar tracking. https://www.space.com/arecibo-observatory-loss-for-planetary-defense-asteroids https://www.space.com/arecibo-observatory-loss-for-planetary...