MAGELLAN MISSION

The Magellan spacecraft was launched on the 4th May 1989, and entered into orbit about Venus on the 10th August 1990. Magellan is named after the sixteenth-century Portuguese explorer who circumnavigated the Earth. The launch of Magellan was unusual, as it was the first interplanetary spacecraft to be launched from the Space Shuttle. The Space Shuttle carried Magellan into Earth orbit, and released the spacecraft from the Shuttle's cargo bay. Magellan's engine fired, and took the spacecraft on a trip round the Sun - the Sun's gravity was used to swing the spacecraft towards Venus.

The launch of Magellan from the Space Shuttle.

The atmosphere of Venus is dense and opaque, and prevents any optical view of the planetary surface. Consequently, the principle instrument on board Magellan was a radar. This worked by sending millions of energy pulses per second through the atmosphere to the surface, which reflected them back to the spacecraft. The atmosphere is transparent to radar, and in this way Magellan was able to map Venus.

Magellan was placed into a polar orbit. That is, it circled Venus travelling from pole to pole, building up a radar image. On each orbit, the planet's rotation meant that a different part of the surface became available for mapping. Within the four years of its operation, Magellan mapped 98% of the surface of Venus at resolutions never before achieved. The Magellan radar data forms the basis for the 3D globe in this CD, along with many of the surface pictures.

After the completion of the radar mapping, Magellan also made maps of the Venusian gravity field, providing further information concerning the geology of Venus.

Magellan's life was ended with a deliberate journey through the atmosphere. This was to allow the spacecraft to collect information concerning the atmosphere as Magellan descended towards its destruction. It is thought that some of the pieces of Magellan may have hit the surface.