A study of central cryogenic cooling system for the comet rendezvous spacecraft

Several science instruments required temperatures between 100 K and 120 K on a proposed Halley Flyby, Tempel-2 Rendezvous Mission. Significant features of the thermal environment are a large variation in heliocentric as well as comet distance, very large solar panels for a Solar Electric Propulsion stage, and the comet dust environment. The best cooling is achieved by one central radiative cooler connected by insulated cryogenic heat pipes to the instruments. The conceptual design is of a single-stage rectangular shielded radiator deployed on a boom some distance from the spacecraft bus and solar panels. Thermal modeling determined sensitivity to solar and comet distance and was used to optimize cooler geometry.