One of NASA's most successful planetary missions was assembled from leftover hardware: a Voyager bus and antenna, Galileo computers, Ulysses radio tubes, and a space shuttle auxiliary tank. This episode tells the story of Magellan, born in 1983 from the cancelled VOIR proposal, delayed by the Challenger disaster and the loss of its Centaur-G booster, and finally launched from the shuttle Atlantis in May 1989 on a one-and-a-half-year route to Venus. We explain the tense Star 48B orbital insertion burn, steered by 24 hydrazine thrusters because the craft could not be spin-stabilized.

At Venus, Magellan's synthetic aperture radar used Doppler shifts to simulate an antenna kilometers long, mapping 98 percent of a surface hidden under sulfuric acid clouds while alternating every 3.26-hour orbit between scanning and beaming data home. The maps re ...