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The Magellan mission was conceived in the 1970s as the Venus Orbiting Imaging Radar. JPL had a number of engineers and scientists interested in using synthetic aperture radar to study the planets. This type of radar could see through clouds and produce radar images much as a camera does, but using different wavelengths. Because Venus is completely shrouded in clouds, this was the only way the surface of Venus could ever be seen. JPL's Charles Elachi, later to become the lab's director, did the initial studies for this mission in the early 1970s, but it took many years to get the mission approved.
Magellan was a low-cost mission, with the spacecraft built largely of spare parts left over from previous missions. Cost pressures also resulted in an unusual operational concept for the mission. It only had one antenna for both the radar and the radio link back to Earth, so the spacecraft had to point at Venus to take data, and after its tape recorders had filled, turn toward Earth to send the data.
Originally expected to map 84 percent of the surface before running out of fuel, the spacecraft operated much longer than anticipated and completed mapping 98 percent of the surface. Magellan's radar revealed that Venus' surface was rugged, with large volcanic mountains and ridges, but few large craters. This suggested to the mission's scientists that Venus had been essentially resurfaced sometime in the last half billion years, unlike the moon or Mars. On Oct. 11, 1994, Magellan was finally flown into the Venusian atmosphere to gather data on a new technique named "aerobraking." The spacecraft returned data and ultimately burned up in the atmosphere. |
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