One of the more successful efforts by the
US National Aeronautics and Space Administration, the Magellan probe mapped the surface of
Venus using
imaging radar, and collected
gravity data for the construction of a
digital elevation model of Venus.
Magellan was launched on May 4,
1989. It arrived at Venus on August 10,
1990, and performed its mission until radio contact was lost on October 12,
1994.
Data from Magellan led scientists to an astonishing discovery about Venus: The entire surface of the planet is the same age, about 500 million years old!