<title>Laser-based particle protection system for spacecraft in low-earth orbit</title>

Abstract

A particle deflector operating on the principle of laser-induced ablation may eliminate collisions between spacecraft and small debris in low earth orbit. A practical system is constrained to deflecting particles up to a few grams mass with velocities up to 10 km/s. Fundamental concerns for such a system include particle detection and tracking, beam formation, beam steering, and energy coupling to the target. The limiting technology is the detection and tracking system, which must located fast moving (10 km/s) objects 1 cm or smaller in diameter at distances greater than 1 km. We show that a 2000 J laser beam can deflect at 10 mrad a 1-g particle approaching at 10 km/s--adequate to protect a modest sized (approximately 10 m) space structure if the particle is intercepted while still 1 km away. Methods for delivering large optical power densities onto a small (approximately 1 cm) target over moderate (1000 m) distances are proposed.