The Magellan spacecraft, also referred to as the Venus Radar Mapper, was a 1,035-kilogram robotic space probe launched by NASA on May 4, 1989, to map the surface of Venus using Synthetic Aperture Radar and measure the planetary gravity. It was the first interplanetary mission to be launched from the Space Shuttle, the first to use an inertial upper stage booster and was the first spacecraft to test aerobraking as a method for circularizing an orbit. Magellan was the fourth successful, NASA funded mission to Venus and ended an eleven year U.S. interplanetary exploration hiatus.

Beginning in the late 1970s, scientists pushed for a radar mapping mission to Venus. First seeking to construct a spacecraft titled, Venus Orbiter Imaging Radar, it became obvious the mission would be outside the limits of the budgetary constraints during the following years and was subsequently canceled in 1982. Recommended by the Solar System Exploration Committee, a stripped down mission proposal was resubmitted and accepted as the Venus Radar Mapper in 1983. The proposal included a limited focus and a single primary scientific instrument. In 1985, the mission was renamed Magellan, after the sixteenth-century Portuguese explorer Ferdinand Magellan, for his exploration, mapping and circumnavigation of the Earth, a goal this mission would have for Venus.