Accession Number : ADA181618

Title :   Hypervelocity Oxygen Source for the Study of Atom-Surface Interactions.

Descriptive Note : Final rept.,

Corporate Author : AERODYNE RESEARCH INC BILLERICA MA

Personal Author(s) : Freedman,Andrew ; Unkel,William

PDF Url : ADA181618

Report Date : Apr 1987

Pagination or Media Count : 62

Abstract : Space-based facilities face an unexpectedly hostile environment at orbital altitudes due to chemical interaction with atomic oxygen at high velocities (typically 8 km/s). Shuttle-based experiments indicate substantial degradation and erosion of various materials which face into the atmospheric wind. This document reports the efforts of a project intended to design a high velocity, high flux atomic oxygen beam source capable of simulating the space environment. Also included are plans for a vacuum apparatus which will provide for the diagnostic techniques needed to evaluate the source peformances as well as allow for materials testing. The oxygen atom beam source is based on the concept of admixing a small quantity of molecular oxygen into a gas stream of helium that had been electric discharge heated using a commercially available plasma touch. Extensive modeling has suggested improvements in a previous version of the source that should allow production of 8 km/s beams with atomic oxygen fluxes of 1 x 10 to the 17th power/cm sq/s at 10 cm distance from the source aperture. Metastable atom production should be minimal (0.001). The major changes entail a new oxygen injection system and enlargement of the source aperture. This latter change requires the incorporation of a Campargue style 'zone-of-single' nozzle skimmer system in the vacuum apparatus in order to handle the increased gas load. Schematics of the redesigned source and vacuum apparatus are included.

Descriptors :   *INTERACTIONS, *ATOMS, *OXYGEN, CHEMICAL REACTIONS, DEGRADATION, DIAGNOSIS(GENERAL), ELECTRIC DISCHARGES, ENEMY, ENVIRONMENTS, EROSION, GAS FLOW, GASES, HELIUM, HIGH VELOCITY, HYPERSONIC VELOCITY, INJECTION, ALTITUDE, ATOMIC BEAMS, MATERIALS, METASTABLE STATE, MOLECULAR PROPERTIES, ORBITS, CHEMICAL REACTIONS, OXYGEN EQUIPMENT, PLASMAS(PHYSICS), PRODUCTION, SCHEMATIC DIAGRAMS, SOURCES, SPACE ENVIRONMENTS, SURFACES, TEST METHODS, TOUCH, VACUUM APPARATUS, WIND

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE