The Space Infrared Telescope Facility (SIRTF), the fourth of the Great Observatories, will look through a new window on the universe. Using SIRTF, the astronomical community will be able to explore the infrared universe with a depth and precision complementary to that achieved by NASA’s other Great Observatories-the Hubble Space Telescope (HST), the Advanced X-ray Astrophysics Facility (AXAF), and the Compton Gamma Ray Observatory (GRO). SIRTF will achieve unprecedented infrared sensitivity by fully utilizing a new generation of infrared detector arrays. The new detectors, combined with an 85-cm cryogenic telescope, will allow SIRTF to provide scientific capabilities so impressive that SIRTF was designated the highest priority major new mission for all US astronomy in the 1990s. This paper will provide a review of the SIRTF program—the science, mission design, facility, and the instruments. Emphasis will be placed on those features of the program which will allow us to realize the great scientific potential of the Observatory in a resource-constrained environment
