Launch from Cape Canaveral (KSC) and landing on Edwards AFB, Runway 23.

The launch was postponed for 22 minutes and 30 seconds due to a main engine liquid hydrogen prevalve close remote power controller showing a faulty 'on' indication.

This was the second Shuttle mission dedicated to Department of Defense, and most information about it remained classified. For the second time, NASA did not provide pre-launch commentary to the public until nine minutes before liftoff. William Pailes became as MSE the second military astronaut in space. The crew deployed two military communications satellites DSCS III (USA-11 and USA-12). Both were launched into stationary orbits by an Inertial Upper Stage. The DSCS satellites used X-band frequencies (8/7 GHz). Each DSCS-III satellite had a design life of ten years, although several of the DSCS satellites have far exceeded their design life expectancy.
DSCS-III spacecraft weighed 2,580 pounds. The spacecraft's rectangular body was 6 feet x 6 feet x 7 feet (1.8 x 1.8 x 2.1 meters); with a 38-foot (11.5 meters) span with solar arrays deployed. Phase III solar arrays generated 1,100 watts, decreasing to 837 watts after five years. Each DSCS III satellite costs about $100,000,000.
The DSCS III satellites provided substantial capability to support high-capacity links between all terminals and to permit AJ communications and control of the satellites during crisis and contingency situations. DSCS III satellites operate in the X-band region, providing uplink services in the 7900-8400 MHz band and downlink services in the 7250-7750 MHz band. The frequency spectrum is divided into six bands by the use of six limited-bandwidth transponders which are switchable between antennas by DSCS ground control. Communications performance is optimized by allowing these independent transponders to be connected to various types of antennas. This permits selection of Earth coverage (EC), area coverage (AC), spot coverage, grouping of channels with similar modulation, and antenna gain-to-noise temperature (G/ T) ratios to meet user needs. Any type of modulation or multiple access may be used since the transponders do not process or modulate the signals. The DSCS III satellites are three-axis stabilized (geostationary) vehicles that have a dry weight of 1,950 pounds (884 kg) and a maximum weight of 2,550 pounds (1,156 kg) with propellant. The dimensions of the satellite body are approximately 80 inches (6.5 feet or 1.98 meter) on each side and 460 inches (38 feet or 11.58 meters) in length, with solar arrays (SA) deployed. Communications antennas include a receive 61-beam multibeam antenna (MBA) and two transmit 19-beam MBAs, two receive and two transmit Earth coverage horns (ECH), and a transmit-only gimballed dish antenna (GDA). In addition, there is one transmit and one receive SCT UHF antenna.
The DSCS III Communications Subsystem includes six independent RF channels, jammer location electronics (JLE), one receive 61-beam MBA, two receive ECHs (E1R and E2R), two transmit 19-beam EC/ narrow coverage (NC) MBAs (M1X and M2X), one transmit GDA, and two transmit ECHs (E1X and E2X). Channels 1 and 2 are designated as high-power channels and each operates with a 40-watt TWTA. Channels 3 to 6, the low power channels, operate with a combination of 10-watt TWTAs/ high efficiency solid-state amplifiers (HESSA), and linear solid-state amplifiers (LSSA). The last four DSCS III satellites scheduled for launch (B-8, B-11, B-6, and A-3) will receive performance upgrades through the DSCS SLEP. Responding to the Services' need for more capacity, the original DSCS III SLEP has been revised. The revised SLEP provides improved satellite capability for the next four DSCS satellites to be launched with the first scheduled in July 1999 and the fourth in fiscal year (FY) 2003 (a fifth satellite is currently unfunded). Major revised DSCS upgrades to the DSCS III satellite include increased transponder bandwidth and 50-watt TWTA in all six channels. The 50-watt TWTA and bandwidth addition is predicted to provide a 700 percent increase in tactical communications capacity.

It was the first spaceflight of orbiter Atlantis.