SMALL HELIUM-COOLED INFRARED TELESCOPE FOR SPACELAB 2.

A helium-cooled telescope of 15 cm aperture is being constructed for high sensitivity IR astronomical observations from Spacelab 2. A focal plane array of ten detectors provides a total field of view of 3 degree and covers the wavelength regions 4. 5-8. 5 mu m, 6-7 mu m, 9-16 mu m, 18-30 mu m, and 60-120 mu m. A redundant all-sky survey will be conducted by repeated scanning of the sky during many orbits of the spacecraft. High redundancy will allow discrimination among variable and constant celestial sources and several types of variable nearby sources. The principal result of the survey will be the absolute flux measurement of low surface brightness, large scale celestial IR emissions, but it will also extend existing IR sky surveys by a factor of 10 in point-source sensitivity. The experiment will also measure contaminants in the Shuttle environment, test the technology of storage and utilization of large quantities of superfluid helium in space, demonstrate techniques for sensitive IR measurements from space, and test mechanical designs for future IR telescopes for the Space Shuttle.