Laser broom

Artistic representation

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.

Technical description

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.[1] 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.[2] 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.[3] 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.[4]

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.[5] This work was summarized in an article in Wired magazine.[6]

Applications and proposed project

The Space Shuttle routinely showed evidence of "tiny" impacts upon post-flight inspection.[7]

Project Orion was a proposed laser broom project estimated to cost $500 million in the 1990s.[8][9]

References

  1. ↑ Dr Sten Odenwald (1997). "Where can I get information about orbiting space junk?". Ask the Astronomer - Archive of Astronomy Questions and Answers. Astronomy Cafe. Retrieved 2007-03-26.
  2. ↑ Jonathan Campbell, "Using Lasers in Space: Laser Orbital Debris Removal and Asteroid Deflection", Occasional Paper No. 20, Air University, Maxwell Air Force Base, December 2000.
  3. ↑ Ivan Bekey, "Project Orion: Orbital Debris Removal Using Ground-Based Sensors and Lasers.", Second European Conference on Space Debris, 1997, ESA-SP 393, p. 699.
  4. ↑ Bates, Daniel (2011-03-16). "Nasa to shoot lasers at space junk around Earth to prevent collisions with satellites". Mail Online. Retrieved 2011-03-24. The theory is that the photons in laser beams carry a tiny amount of momentum in them which, under the right circumstances, could nudge an object in space and slow it down by 0.04 inches per second. By firing a laser at a piece of junk for a few hours it should be possible to alter its course by 650ft per day. ... While that won’t be enough to knock it out of orbit, it could be sufficient to avoid a collision with a space station or satellite. The theory marks a change in approach from previous research which looked into using expensive military Star Wars-style lasers to destroy space junk.
  5. ↑ Dr Claude Phipps (2011). "Removing Orbital Debris with Lasers". arXiv:1110.3835 Freely accessible.
  6. ↑ Adam Mann (2011). "Space Junk Crisis: Time to Bring in the Lasers". Space Junk Crisis: Time to Bring in the Lasers. Wired. Retrieved 2016-06-22.
  7. ↑ Weinstock, Maia (5 September 2000). "Orbiting Junk Continues to Threaten International Space Station". Space.com. Archived from the original on 2000-11-21. Retrieved 2008-02-03.
  8. ↑ Ivan Bekey (May 1997). "Orion's Laser: Hunting Space Debris". Aerospace America. AIAA. Retrieved 2011-05-08.
  9. ↑ "Satellite Smashers". Air & Space Magazine. March 1, 2008. Retrieved August 18, 2011.

Further reading

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