Laser Propulsion
Summary:
LTI is developing a method of propelling aircraft and spacecraft through the use of ground-based lasers. Should a megawatt laser become available, LTI plans to send a small satellite—weighing less than a kilogram—into orbit via laser propulsion by 2005. This technology is derived in part from BMDO, then the SDIO, research into using laser propulsion for launching small surveillance satellites. Reducing satellite launch costs would be the primary commercial potential of laser propulsion, particularly as smaller “micro-” and “nano-” sized satellites come into use.
Technology Description:
LTI is developing a method of propelling aircraft and spacecraft through the use of ground-based lasers. Instead of carrying a heavy load of chemical fuel, a spacecraft will be propelled by a laser beam from a ground power station. Underneath the vessel will be a laser reflector and nozzle. The laser beam striking this reflector superheats the air, raising the air pressure underneath the craft to create a series of short blasts that pushes it upward. The craft itself achieves stability by spinning at a rapid rate.
Should a megawatt laser become available, LTI is planning to send a small satellite—weighing less than a kilogram—into orbit via laser propulsion by 2005. “Laser lightcraft” prototypes have already been tested successfully on a more modest scale. During the first test at White Sands Missile Range in New Mexico in 1997, the saucer-sized disk traveled upwards one foot, propelled by a 10-kilowatt pulsed carbon dioxide (CO2) laser with an 18-microsecond pulse. Successive launches have gone to progressively higher altitudes. The latest flight, in July 1999, reached 127 ft. The test disks, spanning 11 centimeters, weighed 25 to 29 grams each.
High-powered lasers, capable of kilojoule-level pulses, will be needed to propel craft farther. The company estimates that it would take a one megawatt laser to lift a one kilogram microsatellite into low-Earth orbit. Such megawatt lasers, having no current commercial applications, are not presently in production. Work is also needed to refine the propulsion energy converter, the part of the craft that will convert the beamed energy into thrust. The vehicles that LTI plans to produce will be lightweight, low-cost, and suitable for mass-production.
MDA Origins:
In 1989, BMDO, then the SDIO, funded laser propulsion research to launch small satellites for surveillance. Further research has been supported by the U.S. Air Force Research Laboratory and the NASA Marshall Space Flight Center.
Spinoff Applications:
Reducing satellite launch costs is the primary benefit of laser propulsion, particularly as smaller “micro-” and “nano-”sized satellites come into use. NASA is developing hatbox-sized satellites for atmospheric monitoring and in-space laboratory experiments. Laser propulsion would be a cheap way of placing these “microsatellites” in orbit. The U.S. Air Force may need laser propulsion as well—it is investigating the possibility of launching constellations of nanosatellites for secure communications and reconnaissance. Likewise, private industry could test components for radiation hardness and space environment suitability far more cheaply by sending them up to high altitudes with a laser launcher than by conventional rocket.
LTI predicts that laser propulsion, once in widespread commercial use, could eventually reduce launch costs by as much as a factor of a 1000. The company estimates that the electricity needed to propel a one-kilogram microsatellite into orbit will cost only a few hundred dollars, much less than the $10,000 per pound that it costs for a shuttle launch. Plus, unlike chemical rockets, laser propulsion systems can be used repeatedly. And, as the power source is not carried on the spacecraft itself, it has no size or weight restrictions and can be designed for maximum reliability and power.
Long-term prospects for larger lightcraft could include manned trips into low-Earth orbit. Scalability issues still must be addressed for this to happen, however.
Commercialization:
LTI has forged a partnership with a non-profit organization for the creation of improved laser propulsion engine technology. The company needs investors to fund larger prototypes and generate performance data.
Company Profile:
LTI was incorporated in mid-1999 to explore commercial development of beamed energy propulsion technology.
Contact Information:
Leik N. Myrabo, Ph.D.
Lightcraft Technologies, Inc.
1914 Walloomsac Rd
Bennington VT 05201-9762
Tel:802-447-1584
Fax:518-276-2623
email: myrabl@rpi.edu
web: www.lightcrafttechnologies.com
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