Group of seven multilayer insulation (MLI) 'blankets' made for the High Energy Astronomy Observatory C (the third HEAO spacecraft). They provided thermal insulation with multiple layers of aluminized polyimide plastic sheeting. Some layers also provide some structural strength for the blankets with embedded fibers. Because of the thin aluminum coating, they can be conductive, so some blankets have electrical leads to allow any accumulated electrical charge to 'bleed off.' The pieces are various shapes and sizes, ranging from about 7″ x 12″ to 25″ x 16″, and many are in their plastic packaging with cards identifying part and serial numbers; two labels are marked "HEAO-C."
Launched on September 20, 1979, HEAO-C was a gamma-ray and cosmic-ray scanning mission. The spacecraft carried three scientific instruments to map the sky in higher energy regions of the electromagnetic spectrum and of the cosmic ray flux. Each experiment on HEAO-C was thermally isolated with its own thermostatically controlled heaters.
