Magellan spacecraft launched at 7,595 pounds (3,445 kilograms) and operated under NASA Jet Propulsion Laboratory. It carried synthetic-aperture radar, radar altimeter, radiometer, and radio-science gravity experiment. Magellan mapped 98 percent of Venus at high radar resolution and 95 percent of its gravity field, showed a geologically young volcanic world without Earth-like plate tectonics, identified vast lava plains and tectonic structures, and ended with a controlled atmospheric experiment.