STS 41-G was the 13th flight of NASA's Space Shuttle program and the sixth flight of Space Shuttle Challenger. Challenger launched on 5 October 1984, and conducted the second shuttle landing at Kennedy Space Center on 13 October. It was the first shuttle mission to carry a crew of seven, including the first crew with two women (Sally Ride and Kathryn Sullivan), the first American EVA involving a woman (Sullivan), and the first Canadian astronaut (Marc Garneau).

STS-41-G was the third shuttle mission to carry an IMAX camera on board to document the flight. Film footage from the mission (including Sullivan and David Leestma's EVA) appeared in the IMAX movie The Dream is Alive.

On 5 October 1984, Challenger launched from the Kennedy Space Center at 7:03 am EDT, marking the start of the STS-41-G mission. On board were seven crew members – the largest flight crew ever to fly on a single spacecraft at that time. They included commander Robert L. Crippen, making his fourth Shuttle flight and second in six months (Crippen became the first American astronaut to complete two space missions in the same calendar year); pilot Jon A. McBride; three mission specialists – David C. Leestma, Sally K. Ride and Kathryn D. Sullivan – and two payload specialists, Paul Scully-Power and Marc Garneau, the first Canadian citizen to serve as a Shuttle crew member, as well as the first Canadian in space. The mission also marked the first time two female astronauts had flown together.

Sullivan became the first American woman to walk in space when she and Leestma performed a 3-hour EVA on 11 October, demonstrating the Orbital Refueling System (ORS) and proving the feasibility of refueling satellites in orbit.

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.

The SIR-B was an improved version of a similar device flown on the OSTA-1 package during STS-2. It had an eight-panel antenna array measuring 35 feet by 7 feet (11 m by 2 m). It operated throughout the flight, but problems were encountered with Challenger's Ku band antenna, and therefore much of the data had to be recorded on board the orbiter rather than transmitted to Earth in real-time as was originally planned.