PROGRAM ASTEC (ADVANCED SOLAR TURBO ELECTRIC CONCEPT). PART 1. CANDIDATE MATERIALS LABORATORY TESTS

• Main Authors: Hurtt, W W, Blakney, T L, Cunnington, G R, Bradshaw, W G, Pollard, H E
• Format: Report
• Language: English
• Subjects: ALUMINUM; ASTEC(ADVANCED SOLAR TURBO ELECTRIC CONCEPT); COATINGS; COMPOSITE MATERIALS; DEGRADATION; Electric Power Production and Distribution; ELECTRON IRRADIATION; EMISSIVITY; EPOXY RESINS; EXPANDED PLASTICS; HONEYCOMB CORES; MECHANICAL PROPERTIES; NICKEL; OXIDES; PHENOLIC PLASTICS; REFLECTION; REFLECTORS; SILICON COMPOUNDS; SOLAR COLLECTORS; SOLAR RADIATION; SPACE ENVIRONMENTS; SPACECRAFT COMPONENTS; SPECIFIC HEAT; THERMAL CONDUCTIVITY; THERMAL EXPANSION; THERMAL PROPERTIES; THERMAL STABILITY; ULTRAVIOLET RADIATION

A space power system of the type envisioned by the ASTEC program requires the development of a lightweight solar collector of high reflectance capable of withstanding the space environment for an extended period. A survey of the environment of interest for ASTEC purposes revealed 4 potential sources of damage to collector materials: solar uv radiation, low-energy electrons encountered in the auroral zones, vacuum, and combined temperature levels and thermal cycling. A laboratory test program was conducted to determine the basic thermophysical, optical, and mechanical properties of materials developed by the solar-collector industry for use in the ASTEC program, and to test the effects of space environment on these materials. Of 6 material systems selected for testing, 4 were epoxy-bonded metal systems, 1 was phenolic foam with a metal surface, and 1 was polyurethane-rigidized nylon with an aluminized mylar surface. Honeycomb configurations proved to be far superior from a structural standpoint to the nonhoneycomb types. All the reflective surfaces degraded to some extent in the simulated ASTEC environment, but material systems with bare metal surfaces were significantly more stable than systems with silicon oxide overcoatings. In addition, these systems had a higher initial reflectance. No material proved to be ideally suited in all respects for use in the ASTEC solar collector. See also Part 2, AD480103.