The NASA Ames Research Center has developed a baseline design for a One Meter Cryogenic Optical Test Facility
(OMF) incorporating a liquid helium Dewar for cryogenic optical testing of one-meter-class mirrors, principally the Space
Infrared Telescope Facility (SIRTF) primary mirror. The primary requirements for the test facility are as follows: 1) The
facility must be capable of interferometrically testing any mirror, positioned face-up or face-down, with a diameter less than
1.5 meters and a radius of curvature from 1.5 to 5.5 meters. 2) The facility must achieve and maintain, for 24 hours, a
mirror temperature of 4 K with a maximum radiative heat load of less than 500 mW to the mirror, using stored liquid helium
and liquid nitrogen. 3) The facility must include a vibration-isolated metrology structure between the test mirror and an
external interferometer. 4) The facility must be operated by two persons and a test, starting from the mounting of a mirror to
the removal of a mirror, must be conducted within one week.
|