Launch from Cape Canaveral (KSC); landing on Edwards AFB.

First mission of orbiter "Discovery". Planned launch was delayed twice because of a variety of technical problems, including rollback to the VAB to replace a main engine.

Deploying of communications satellites SBS-D (USA), Telstar 3-C (USA) and Syncom IV-2/Leasat 2 (US Navy); solar wing (31 m) was extended from payload bay. The wing carried a number of different types of experimental solar cells and was extended to its full height several times. It was the largest structure ever extended from a manned spacecraft and demonstrated the feasibility of large lightweight solar arrays for future application to large facilities in space such as the Space Station.

Walker was the first commercially sponsored payload specialist to fly aboard the Shuttle. He worked on the Continuous Flow Electrophoresis System .