Lightcraft
A lightcraft is a spacecraft to which a ground-based pulse laser or maser supplies the necessary propulsion energy. The laser shines on a parabolic reflector on the underside of the missile. At the focal point of the reflected beam, extremely high temperatures of 10,000 to 25,000 ° C arise. Matter in this area expands explosively due to the extreme warming , transfers part of the impulse of the gas particles to the reflector and thus accelerates the missile. During the break between two pulses, cool gas flows behind the reflector again, which accelerates the missile again with the next pulse.
During flight within the earth's atmosphere , the atmospheric gas is heated; for flight in space (on earth from approx. 11 km altitude) a supporting mass , such as Delrin , must be taken along, which is then brought into the focal area behind the reflector and when heated, propels the spacecraft.
This propulsion concept is intended for the launch of small satellites weighing up to a few kilograms. Lasers with powers of up to 1000 kW are required for this.
Advantages compared to conventional drives
- Very high payload ratio due to the high specific impulse due to the high temperature
- Low costs, since no complex system for fuel delivery and combustion control is required
- Environmentally friendly, as there are few, possibly toxic, combustion gases.
trouble
- The laser power required for this cannot be achieved with today's means.
- The divergence of the laser beam makes with increasing distance for a reduction of the useful power for the drive.
- complicated path control and attitude control for the missile.
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This concept has been tested in the laboratory with model missiles for years. Because of the difficulties mentioned (in particular due to the lack of laser power), a practical application is not yet in sight. The Air Force Research Laboratory (AFRL) , a research facility of the United States Air Force, is researching the possibility of launching small satellites using this technology.
Web links
- science explorer
- Lightcrafttechnologies
- Leonard David: Riding Laser Beams to Space
- Lightcraft impulse measurements under vacuum and under atmospheric pressure, without and with Delrin (DLR)
- Feasibility study of a laser ramjet single-stage-to-orbit vehicle (AIAA) (PDF; 1.6 MB)
Individual evidence
- ↑ Lightcraft: A Laser Push to Orbit centauri-dreams.org, September 14, 2009
- ↑ Riding the Highways of Light nasa.gov, April 16, 1999, accessed November 22, 2010
- ↑ Lightcraft Propulsion for Launching a Small Satellite defensetechbriefs.com, February 1, 2010, accessed November 22, 2010
- ↑ Lightcraft Experiments Continue centauri-dreams.org, September 15, 2009