The NASA Space Science Enterprise has 2 themes requiring large, lightweight cryogenic mirrors: Astronomical Search for Origins and Planetary Systems (ASO) and the Beyond Einstein Initiative of the Structure and Evolution of the Universe (SEU). The long wavelength Far Infrared/Submillimeter (FIR/SMM) instruments of Space Technology 9, the SAFIR Observatory, the Space InfraRed Interferometric Telescope (SPIRIT), and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) missions require the highest possible signal-to-noise ratio to resolve the emissions of protogalactic objects and galaxies. The development of 10-25 meter diameter cryogenic optics for the 20-800 microns bandwidth, with an areal density <5 kg/m2, and a surface figure specification of lambda/14 at 20 microns is required. There is a premium for wavelengths >100 microns to achieve mirror temperatures <10K. In fact, at 200 microns wavelength, the point source sensitivity is more dependent on temperature than on aperture size! During the Phase II project Schafer proposes to design, build and test a 0.5-m diameter actively cooled SLMSTM
Far Infrared Submillimeter Prototype (FISP) mirror suitable for NASA FIR/SMM missions, thus maturing SLMSTM
cryogenic mirror technology to TRL 5-6. Active cooling of SLMSTM
mirrors to 4K is an enabling technology for future FIR/SMM instruments.