STS-33 was originally scheduled to launch on November 20, 1989, but was delayed because of problems with the integrated electronics assemblies which controlled the ignition and separation of the shuttle's
solid rocket boosters (SRBs). STS-33 was the third night launch of the Space Shuttle program, and the first since shuttle flights resumed in 1988 following the
Challenger disaster of 1986. During the mission,
Discovery deployed a single satellite,
USA-48 (1989-090B). Experts believe that this was a secret
Magnum ELINT (ELectronic INTelligence) satellite headed for
geosynchronous orbit, similar to that launched by
STS-51-C in 1985, making this mission essentially a duplicate of that earlier mission. According to Jim Slade of
ABC News, USA-48 was intended to eavesdrop on military and diplomatic communications from the
Soviet Union, China, and other
communist states. The satellite deployed by STS-33 was a replacement for the one launched by STS-51-C, which was running out of the maneuvering fuel required for keeping its station over the
Indian Ocean. However, astronaut
Gary E. Payton stated in 2009 that STS-51-C's payload is "still up there, and still operating". STS-33 was observed by the telescope of the
U.S. Air Force Air Force Maui Optical and Supercomputing observatory (AMOS) during five passes over
Hawaii. Spectrographic and infrared images of the shuttle obtained with the Enhanced Longwave Spectral Imager (ELSI) were aimed at studying the interactions between gases released by the shuttle's primary
reaction control system (RCS) and residual atmospheric
oxygen and
nitrogen species in orbit. The landing was initially scheduled for November 26, 1989, but was postponed for a day because of strong winds at the landing site.
Discovery landed at Edwards Air Force Base, California, on November 27, 1989, at 7:30:16 p.m. EST, after a mission duration of 5 days, 0 hour, 6 minutes, and 46 seconds. == See also ==