Nine hours after liftoff, the 5,087 pounds (2,307 kg) Earth Radiation Budget Satellite (ERBS) was deployed from the payload bay by the RMS robot arm, and its on-board thrusters boosted it into orbit 350 miles (560 km) above the Earth. ERBS was the first of three planned satellites designed to measure the amount of energy received from the Sun and reradiated into space. It also studied the seasonal movement of energy from the tropics to the polar regions.

Another major mission activity was the operation of the Shuttle Imaging Radar-B (SIR-B). The SIR-B was part of the OSTA-3 experiment package in the payload bay, which also included the Large Format Camera (LFC) to photograph the Earth, another camera called MAPS which measured air pollution, and a feature identification and location experiment called FILE, which consisted of two TV cameras and two 70 mm still cameras.