Lightcraft

Lightcraft being propelled by laser

A lightcraft is a space- or air-vehicle driven by laser propulsion. Laser propulsion is in early stages of development. Lightcraft uses an external source of laser or maser energy to provide power for producing thrust. The laser/maser energy is focused to a high intensity in order to create a plasma. The plasma expands, producing thrust.[1]

A lightcraft is distinct from a solar sail because it is dependent on the expansion of reaction mass to accelerate rather than being accelerated by light pressure alone.

Types

In one type of lightcraft, the laser shines on a parabolic reflector on the underside of the vehicle that concentrates the light to produce a region of extremely high temperature. The air in this region becomes heated and expands violently in a laser-supported detonation, producing thrust.

In other lightcraft concepts, the laser arrives at the vehicle from above, and operates as an ablative laser tractor beam.[2] This may have applications in the removal of space debris.[3]

Description

When a lightcraft is in the atmosphere, air is used as the propellant material (reaction mass). In space, a lightcraft would need to provide the propellant material from onboard tanks or from an ablative solid. By leaving the vehicle's power source on the ground and by using ambient atmosphere as reaction mass for much of its ascent, a lightcraft could potentially be capable of delivering a very large percentage of its launch mass to orbit. It could also potentially be inexpensive to manufacture.

At the current stage of development, the bottom-lasered type of lightcraft exist as small hand-sized test specimens which have attained altitudes of a few hundred feet. In 1999, tests by Leik Myrabo in cooperation with the US Army at White Sands Missile Range demonstrated the basic feasibility of using ground-based lasers to propel objects in this way. The test succeeded in reaching over one hundred feet, which compares to Robert Goddard's first test flight of his rocket design. In 2000, a new flight record was set with a flight lasting 10.5 seconds and reaching 72 meters (236 feet).[1]

A lightcraft's propulsion is dependent on the external laser's power and so propulsive power is not limited to that generated by on-board machinery (rockets).[1]

See also

References

  1. 1 2 3 Approaching Warp Speed: Advanced Space Propulsion, NewSpace 2010 conference panel discussion, 2010-07-25, Lightcraft segment, Leik Myrabo - Rensselaer Polytechnic Institute, Spacevidcast video, at time 10:00-32:00, accessed 2010-07-30.
  2. ↑ Sinko, John (September 17, 2010). "Laser Ablation Propulsion Tractor Beam System". Journal of Propulsion and Power. Retrieved 2010-09-17.
  3. ↑ Shane (September 17, 2010). "Laser Beams to Clean Up Space Junk". GoArticles.com. Retrieved 2010-09-17.
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