Challenger launched from Kennedy Space Center on July 29, 1985 at 5:00 PM EDT and landed at Edwards Air Force Base on August 6 at 12:45 PM PDT. The shuttle orbited 127 times at an altitude of 173 nautical miles at an inclination of 49.5 degrees and travelled 3.3 million miles.
The Spacelab-2 payload consisted of an igloo and three pallets in the payload bay, containing scientific instruments dedicated to life sciences, plasma physics, astronomy, high-energy astrophysics, solar physics, atmospheric physics and technology research.
A major objective of the mission was to verify the performance of the Spacelab systems with the orbiter as well as to measure the environment created by the vehicle in space.
The launch countdown July 12 halted at T-3 seconds after main engine ignition when a malfunction of the number two space shuttle main engine (SSME) coolant valve caused a shutdown of all three main engines. The launch on July 29 was delayed 1 hour, 37 minutes due to a problem with the table maintenance block update uplink. 5 minutes, 45 seconds into ascent, the number one main engine shutdown prematurely, resulting in an Abort To Orbit (ATO) trajectory.
Primary payload was Spacelab-2. Despite abort-to-orbit, which required mission replanning, mission declared success. Special part of modular Spacelab system, the Igloo, located at head of three-pallet train, provided on-site support to instruments mounted on pallets.
Main mission objective was to verify performance of Spacelab systems and determine interface capability of orbiter, and measure environment induced by spacecraft. Experiments covered life sciences, plasma physics, astronomy, high-energy astrophysics, solar physics, atmospheric physics and technology research.
Challenger was crewed by Commander Gordon Fullerton, Pilot Roy D. Bridges, Mission Specialists F. Story Musgrave, Anthony W. England, and Karl G. Henize, and Payload Specialists Loren W. Acton and John David F. Bartoe.