STS-41B

On this mission the first untethered space walks were carried out by McCandless and Stewart, using the manned maneuvering unit. The WESTAR-VI and PALAPA-B2 satellites were deployed, but failure of the Payload Assist Module-D (PAM-D) rocket motors left them in radical low-Earth orbits. The German-built Shuttle Pallet Satellite (SPAS), originally flown on STS-7, became the first satellite refurbished and carried back into space. SPAS remained in the payload bay due to an electrical problem with Remote Manipulator System (RMS). The RMS manipulator foot restraints were first used to practice procedures performed for Solar Maximum satellite retrieval and repair planned for next mission. Integrated Rendezvous Target (IRT) failed due to an internal issue. Five Get Away Special canisters flown in the cargo bay and Cinema-360 camera were used by crew. Other payloads included: Acoustic Containerless Experiment System (ACES); Monodisperse Latex Reactor (MLR); Radiation Monitoring Equipment (RME), and Isoelectric Focusing (IEF) payload.