STS -39 (English Space Transportation System) is a mission name for the U.S. Space Shuttle Discovery NASA. The launch took place on 28 April 1991. It was the 40th Space Shuttle mission and the twelfth flight of the space shuttle Discovery.


  • Michael Coats ( 3 Space ), Commander
  • Blaine Hammond ( first space flight), Pilot
  • Guion Bluford ( third space flight), Mission Specialist
  • Gregory Harbaugh ( first space flight), Mission Specialist
  • Richard Slash (1st space flight), Mission Specialist
  • Donald McMonagle ( first space flight), Mission Specialist
  • Charles Veach ( first space flight), Mission Specialist

Mission overview

The launch was originally scheduled for March 9. Three weeks ago, just days after the Discovery was rolled out to the launch pad, workers discovered the hinge flaps, where the fuel lines of the outer tank empty into the Orbiter, fine cracks. It was therefore decided to take the shuttle back to the construction hall. The compounds were replaced and reinforced by those of the shuttle Columbia. On April 1, the shuttle came back to the launch pad, the launch has been set for April 23. However, during the refueling of the main tank, a sensor indicated values ​​unusual. The sensor and its wiring were replaced and tested. The launch date has been postponed to April 28. The takeoff weight was 112,207 kg.

The mission was conducted for the U.S. Department of Defense. The published payload contained, inter alia: Air Force Program 675 ( AFP675 ), Infrared Background Signature Survey ( IBSS ) with Critical Ionization Velocity ( CIV), Chemical Release Observation (CRO ) and Shuttle Pallet Satellite -II ( SPAS -II) experiments, as well as Space test payload -1 ( STP 1). Which is considered a secret payload contained a Multi-Purpose Release Canister ( MPEC ). Next were on board: Radiation Monitoring Equipment III (RME III) and Cloud Logic to Optimize Use of Defense Systems -IA ( CLOUDS -I).

STS -39 was the first non-secret shuttle mission of the DoD (Department of Defense, DoD). It was before that several shuttle flights for the DoD, these, however, were secret, no information about the payload, the purpose or mission success and their experiments were published. For this mission, only the MPEC experiment was classified as secret.

STS -39 investigated the southern auroral

The team was divided into two teams in order to work around the clock can. Among other activities, the atmosphere was studied and performed experiments with the engines. As part of these experiments, five smaller satellites were exposed, one of which has been recaptured.

The remote manipulator system arm was used for the Shuttle Pallet Satellite -II ( SPAS -II) suspend in the payload bay of the shuttle; this was an IBSS module mounted. This satellite examined, among others, the Discovery during flight maneuvers such as the Malarkey Milkshake. The posting of IBSS was postponed a day on the fourth day of flying, because the financial statements of the CIRRIS ( Cryogenic Infrared Radiance Instrumentation for Shuttle ) was awaited experiment. This experiment observed auroras and other atmospheric phenomena, spent his supply of liquid helium but faster than expected.

As usual had to cope with unexpected tasks the crew. Two tape drives gave after four hours of use on their service and could not be repaired. They had the task to record the observations of the instruments of the AFP -675 experiment. In two hours' work, the astronauts had to lay cable, and a Ku- band antenna to improvise in order to transfer the data directly to the ground station can.

The high orbital orbital inclination of 57 degrees to the equator allowed to fly over large parts of the land mass and investigate. So environmental resources were recorded and documented problem areas.

The landing took place on May 6 at 14:55:35 in Kennedy Space Center, Florida. The Ausrolldistanz was 9,235 feet, the coasting time 56 seconds. The landing was moved to Florida because of the actually planned landing site in California ( Edwards AFB ) prevailed to windy weather. The landing weight was 95,940 kg.