Accession Number : ADA317306

Title :   Concentrators Designed for a Solar Thermal Propulsion Upperstage.

Descriptive Note : Technical paper,

Corporate Author : SRS TECHNOLOGIES HUNTSVILLE AL

Personal Author(s) : Paxton, J. P. ; Gierow, P. A.

Report Date : DEC 1995

Pagination or Media Count : 10

Abstract : Solar Thermal Propulsion (STP), an upper stage propulsion system, requires the use of deployable primary collectors to concentrate incident solar flux. The concentrated solar energy heats an absorber and propellant fluid which is expanded through a nozzle. Three designs are currently being deployed by inflation, and their shape is maintained by a pressure inside the concentrator canopy. Foam rigidized concentrators are deployed by inflation pressure. However, they differ from inflatable concentrators, in that they are rigidized by a foam which is injected between two membranes. Both inflatable and foam rigidized concentrators are constructed using a castable thin film polyimide. These films are cast in resin form and cured on a tooling mandrel. Rigid concentrators are typically thin film composite panels which are deployed by unfolding them from their stowed position. The concentrator design selected for the upper stage depends upon mission requirements, the size of the payload, and the design of the solar rocket system. This paper discusses the current state of the technology for STP, and makes comparisons of techniques for measuring and evaluating symmetrical and off-axis reflectors. Laser ray-trace models are used to measure flux distribution at the focal plane for one off-axis reflector and the slope error is calculated.

Descriptors :   *THERMAL PROPERTIES, *PROPULSION SYSTEMS, *SOLAR ENERGY, MEASUREMENT, POSITION(LOCATION), DEPLOYMENT, MILITARY REQUIREMENTS, DISTRIBUTION, FLUX(RATE), PANELS, THIN FILMS, COMPOSITE STRUCTURES, LASERS, PROPELLANTS, MISSIONS, ERRORS, CONCENTRATION(COMPOSITION), SLOPE, CANOPIES, MEMBRANES, FLUIDS, SOLAR RADIATION, ACCUMULATORS, STORAGE, FOCAL PLANES, INFLATABLE STRUCTURES, RAY TRACING, CASTINGS, FOAM, SOLAR SYSTEM, POLYIMIDE RESINS, SOLAR ROCKETS.

Subject Categories : Thermodynamics
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE