The Orbiting Retrievable Far and Extreme Ultraviolet Spectrometers (ORFEUS)-SPAS payloads were joint DARA (German Space Agency)/NASA missions flown on two shuttle flights. The first flight was aboard the shuttle Discovery. The second flight was aboard Columbia. The free-flying ORFEUS-SPAS platform was designed to be deployed and and retreived from the shuttle. The three instruments on the ORFEUS were designed to provide astronomical ultraviolet spectroscopic observations over the wavelength range from 40 to 140 nanometers. The three instruments were:
- Tübingen Ultraviolet Echelle Spectrometer (TUES); (PI) Prof. Michael Grewing; University of Tübingen
- Berkeley Extreme and Far-UV Spectrometer (BEFS); (PI) Dr. Mark Hurwitz; University of California, Berkeley. This instrument was called the Extreme Ultraviolet (EUV) Spectrometer in the ORFEUS-SPAS II Mission Research Announcement. It was later renamed.
- Interstellar Medium Absorption Profile Spectrograph (IMAPS); (PI) Dr. Edward Jenkins; Princeton University
The largest science instrument onboard was a 1-meter telescope. The telescope primary was coated with iridium to improve its light gathering power in the ultraviolet.
Flight 1: September 12 - September 26, 1993 (BEFS, IMAPS)
Flight 2: November 19 - December 7, 1996 (BEFS, TUES)
- Echelle Spectroscopy