Abstract:
A fundamentally new concept is being explored for cryogenic operation of the Space Infrared Telescope Facility (SIRTF). In this concept, the helium dewar and instruments would be launched at liquid helium temperature while the telescope and external radiation shields are at room temperature. Once on-orbit, the telescope and the radiation shields would be cooled radiatively to about 70 K. Helium vapor is then used to bring the telescope down to its final operating temperature of 5.5 K. We present a design which meets SIRTF requirements and discuss its merit.
