STS -43 (English Space Transportation System) is a mission name for the U.S. Space Shuttle Atlantis NASA. The launch took place on August 2, 1991. It was the 42nd Space Shuttle mission and the ninth flight of the space shuttle Atlantis.
- John Blaha ( third space flight), Commander
- Michael Baker ( first space flight), Pilot
- Shannon Lucid ( third space flight ), Mission Specialist
- James Adamson ( second space flight), Mission Specialist
- David Low ( second space flight), Mission Specialist
The launch took place on 2 August 1991. He was originally scheduled for 23 July, but was first postponed to the next day to have time to exchange a wrong mounted electronics, which controls the release of the two solid rocket boosters. The mission was postponed again about five hours before the scheduled start on July 24 due to a faulty engine control unit on the main engine. In order for the ECU was replaced and tested for functionality, start on August 1, has been postponed. The launch was finally postponed by one day due to bad weather again.