Lightcraft
Encyclopedia
A lightcraft is a space-
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 or air-
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

vehicle
Vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

 driven by laser propulsion
Beam-powered propulsion
Beam-powered propulsion is a class of aircraft or spacecraft propulsion mechanisms that use energy beamed to the spacecraft from a remote power plant to provide energy...

. Laser propulsion is currently in early stages of development. Lightcraft use an external source of laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 or maser
Maser
A maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission. Historically, “maser” derives from the original, upper-case acronym MASER, which stands for "Microwave Amplification by Stimulated Emission of Radiation"...

 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.

A lightcraft is distinct from a solar sail
Solar sail
Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....

 because it is dependent on the expansion of reaction mass to accelerate rather than being accelerated by light pressure
Radiation pressure
Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. If absorbed, the pressure is the power flux density divided by the speed of light...

 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.

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
Ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...

 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
Leik Myrabo
Leik Myrabo is an aerospace engineering professor at Rensselaer Polytechnic Institute who has demonstrated the feasibility of using ground-based lasers to propel objects into orbit; possibly reducing orbit-flight costs by a factor of 1000.-Research:...

 in cooperation with the US Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

 at White Sands Missile Range
White Sands Missile Range
White Sands Missile Range is a rocket range of almost in parts of five counties in southern New Mexico. The largest military installation in the United States, WSMR includes the and the WSMR Otera Mesa bombing 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).

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).

See also

  • Beam-powered propulsion
    Beam-powered propulsion
    Beam-powered propulsion is a class of aircraft or spacecraft propulsion mechanisms that use energy beamed to the spacecraft from a remote power plant to provide energy...

  • Elevator:2010
    Elevator:2010
    Elevator:2010 is a competition with monetary prizes similar to the Ansari X Prize, but with the purpose of developing space elevator and space elevator-related technologies...

  • Light sail
    Solar sail
    Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....

  • Space elevator
    Space elevator
    A space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...

  • Non-rocket spacelaunch
    Non-rocket spacelaunch
    Non-rocket space launch is a launch into space where some or all needed speed and altitude is provided by non-rocket means, rather than simply using conventional chemical rockets from the ground. A number of alternatives to rockets have been proposed...


External links

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