China Air Force Engineers propose space-based laser to remove small space junk

Researchers from the Information and Navigation College, Air Force Engineering University and the Institute of China Electronic Equipment System Engineering Company performed computational analysis for using a space-based laser to remove space junk.

The orbital momentum models of small scale space debris and space-based laser station were established. The velocity variation of the space debris ablating by the space-based laser station was analyzed, and the orbit maneuver of the space debris irradiated by laser station was modeled and studied. The variations of orbital parameters of the space debris orbit respectively without and with irradiation of high-power pulsed laser were simulated and analyzed, and the impacts of the inclination and right ascension of ascending node (RAAN) of the space-based laser station on debris removal were analyzed and discussed. The simulation results show that, debris removal is affected by inclination and RAAN, and laser station with the same inclination and RAAN as debris has the highest removal efficiency. It provides necessary theoretical basis for the deployment of space-based laser station and the further application of space debris removal by using space-based laser.

NASA had a 2011 study of a ground-based laser for removing space junk

A laser broom is a proposed ground-based laser beam-powered propulsion system whose purpose is to sweep space debris out of the path of other artificial satellites such as the International Space Station. It would heat one side of an object enough to change its orbit and make it hit the atmosphere sooner.

Lasers are designed to target debris between one and ten centimeters in diameter. Collisions with such debris are commonly of such high velocity that considerable damage and numerous secondary fragments are the result. The laser broom is intended to be used at high enough power to penetrate through the atmosphere with enough remaining power to ablate material from the target. The ablating material imparts a small thrust that lowers its orbital perigee into the upper atmosphere, thereby increasing drag so that its remaining orbital life is short. The laser would operate in pulsed mode to avoid self-shielding of the target by the ablated plasma. The power levels of lasers in this concept are well below the power levels in concepts for more rapidly effective anti-satellite weapons.

NASA research in 2011 indicated that firing a laser beam at a piece of space junk could alter velocity by 0.04 inches (1.0 mm) per second. Persisting with these small velocity changes for a few hours per day could alter its course by 650 feet (200 m) per day. While not causing the junk to reenter, this could maneuver it to avoid a collision.

Other funded research into this area refutes NASA’s claim and demonstrates the precise physics involved, which shows that space debris is re-entered regardless of the direction of laser illumination. Using a laser guide star and adaptive optics, a sufficiently large ground based laser (1 megajoule pulsed HF laser) can deorbit dozens of objects per day at reasonable cost.