Named for the explorer to first circumnavigate the globe, the spacecraft Magellan has navigated the celestial seas to visit our closest sister, Venus. Although other spacecraft have flown to Venus, and the former Soviet Union even sent probes to the surface, Magellan was the first spacecraft to extensively map the Venusian landscape. The continual success of Magellan helps to bolster NASA's interplanetary programs especially in light of the failed Mars spacecraft, Mars Observer, and a still stuck antenna on the craft Galileo, which is on its way to Jupiter. Built mostly from spare parts, Magellan was and continues to be a "cheap thrill".
Primary Mission
Magellan's primary mission was to map the Venusian surface using synthetic aperture radar (SAR). This system had a resolution of about 130 meters in the horizontal direction and 35 meters in the vertical direction. The area covered on the planet or swath was about 25 kilometers by 16000 kilometers for each orbit.
Magellan was placed into a highly elliptical orbit around Venus. The craft mapped the surface when it was closer to the planet then turned around and sent the collected data back to Earth when it was farther from Venus on its orbit. The closest Magellan got to the center of Venus was about 300 kilometers and the farthest away it got was about 8500 kilometers taking about 3 hours and 15 minutes to travel around Venus. Only about 37 minutes an orbit were spent in mapping the surface. The primary mission lasted 243 days or one Venusian day, made 1852 orbits, and 7408 major changes in the orientation of the spacecraft.
Because of a delayed launch date and other physical limitations, gaps in the mapping occurred in certain spots. The south pole was not mapped. Also, gaps occurred when data was unable to be sent back to Earth. This happened twice, once during superior conjunction or when the sun is between Earth and Venus, and during occultation or when Venus is between Magellan and Earth. Because of these gaps, 70 percent of the surface of Venus was mapped during the primary mission.
Sunday, 01-Aug-2004 00:36:47 CDT
CSR/TSGC Team Web
