NASA’s Magellan mission first mapped Venus’s surface in detail using radar.
Magellan launched aboard the space shuttle Atlantis on May 4, 1989, and reached Venus in August 1990. Because thick clouds permanently obscure most of the planet’s surface, ordinary cameras cannot map it from orbit. Magellan used synthetic-aperture radar to image the terrain and radar altimetry to measure elevation.
The spacecraft eventually mapped about 98 percent of Venus’s surface, revealing volcanoes, lava plains, impact craters, and large tectonic features. It is often confused with Pioneer Venus Orbiter, which studied Venus for many years but did not produce Magellan’s detailed global radar map. Magellan ended its mission by entering the atmosphere in October 1994.