Subscale cryo-thermal tests of a large 4 K space telescope

摘要

Theraial performance testing of a large cryogenic system of an open geometry (not contained within a dewar) is problematic due to the proximity of room temperature and very low temperature components. These tests require careful attention to the closeouts between temperature zones to prevent unwanted radiation transfer and to avoid perturbing the system under test. We are demonstrating the possibility of performing these sensitive tests on a small scale which makes the tests faster and cheaper. It also offers the possibility of refining these close-outs, which may not be practical on a full size system. This paper describes a test item modeled on a larger passive and actively cooled future space telescope, and the apparatus used to test it down to 4 K.