Magellan Orbiting Characteristics

• The Magellan spacecraft orbited the planet Venus in the early 1990s. venus image by FotoWorx from Fotolia.com

  The Magellan mission was an unmanned spaceflight to the planet Venus launched by the National Aeronautics and Space Administration (NASA) in 1989. In all, the mission lasted from May 4, 1989, when the spacecraft was launched from Kennedy Space Center aboard a space shuttle, to October 12, 1994, when the spacecraft's transmitter failed. During the course of its mission, Magellan made several different orbits of the planet, each one with different characteristics.

Orbiting Route

• Magellan did a great deal of mapping of the planet Venus. When it did so, it was following a precise orbit. This orbit began over the planet's north pole. From here, the orbit moved clockwise, or west-to-east based on the planet's orientation. During this orbit, the spacecraft's on-board computer sent out a pre-programmed set of commands to maintain its attitude. Once a mapping orbit was finished, the spacecraft was rotated back to transmit information to Earth and then the process began over again.

Cycle 1

• The orbit was broken into four cycles, each of which was designed in order to allow the Magellan spacecraft to map as much of Venus as possible. The cycles were number 1, 2, 3 and 4. Cycle 1 lasted from mid-September 1990 to mid-May 1991. Its goal was to map about 70 percent of the surface. During Cycle I, the spacecraft orbited from as high as 2,000 km at the North Pole and 290 km at one point.

Cycle 2

• Cycle 2 lasted from mid-May of 1991 to mid-January 1992. Its objective was to cover gaps that cycle 1 missed as well as to cover the southern polar parts of the planet.

Cycle 3

• Cycle 3 was from mid-January 1992 to mid-September 1992. It was focused on stereo images, as opposed to the previous cycles which were focused on radar images. This cycle covered around 21 percent of the planet's surface. During this period in the orbit, several equipment failures caused gaps in the images.

Cycle 4

• Cycle 4 was dedicated completely to gravity observations. During this point in the orbit, the spacecraft's antenna was point toward Earth. It measured the radio signal's Doppler shift.

Playback

• At the end of every orbit, the spacecraft was rotated and all of the collected information was sent back the the Deep Space Network on Earth, which has receiving stations in Spain, Australia and the Mojave Desert. Once the playback was finished, the antenna rotated back toward the planet.