NASA's head of planetary defence has revealed what keeps her up at night - tens of thousands of 'city killer' asteroids that remain undetected.

A dead satellite can become a high-speed hazard in an orbit that is already packed with working spacecraft. That risk is why engineers at the University of Colorado Boulder are building what sounds ...

We need an enhanced version of SUNSET to establish a space-based, combined discovery and early-warning system for NEOs (Near Earth Objects). If we use multiple satellites traveling ahead of Earth on ...