Review of Recent Progress During Laser-Powered Lightcraft Flights to Unlimited Altitudes

Abstract

In 1996, the Air Force Research Laboratory's Propulsion Division at Edwards AFB initiated a project that had as its main objective to launch a laser-propelled Lightcraft into a suborbital trajectory within a period of five years in order to demonstrate the concept and its attractive features. The Lightcraft concept is a nanosatellite in which the laser propulsion engine and satellite hardware are intimately shared. The forebody aeroshell acts as an external compression surface (i.e. the airbreathing engine inlet). The afterbody has a dual function as a primary receptive optic (parabolic mirror) for the laser beam and as an external expansion surface (plug nozzle) during the laser rocket mode, which is used only outside the atmosphere. The primary thrust structure is the centrally located annular shroud. The shroud provides air through inlets and acts as a combustion chamber for plasma formation in the airbreathing mode. In the rocket mode, the air inlets are closed, and the afterbody and shroud combine to form the rocket thrust chamber and plug ("aerospike-type") nozzle. The full-scale vehicle has a focal diameter of 1 m and a dry mass of about 1 kg. Fully fueled, this vehicle would have an initial mass of about 2 kg (i.e., a mass fraction of 0.5), and would be launched into orbit with a megawatt-class infrared ground-based laser. It would be a single-stage-to-orbit (i.e., airbreathing (infinite Isp) to M=5 and 30 km; a laser thermal rocket with its own on-board propellant at higher altitudes and in space) using a combined-cycle pulsed detonation engine. Once in space, the Lightcraft will use its 1 m diameter optical system to provide, for example, Earth surveys with 8 to 13 cm resolution in the visible light frequencies from Low Earth Orbit.

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Document Details

Document Type
Technical Report
Publication Date
Sep 26, 2000
Accession Number
ADA409572

Entities

People

  • Carl William Larson
  • Franklin B. Mead

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Chambers
  • Combustion Chambers
  • Earth Orbits
  • Engines
  • Free Flight
  • Laser Beams
  • Lasers
  • Low Earth Orbits
  • Military Research
  • Orbits
  • Payload
  • Test Facilities
  • Thermal Propulsion Systems
  • Vehicles
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Combustion and Flow Dynamics.
  • Missile Defense Systems.
  • Rocket Propulsion.

Technology Areas

  • Directed Energy
  • Space
  • Space - Hall-Effect Thruster
  • Space - Satellites