MAGELLAN MISSION (1989-1994)
Ushas Mons (2,000 m / 2 km - 6,561ft/1.25 mile)
VENUS
The mountain
Ushas Mons (2,000 m / 2 km - 6,561ft/1.25 mile) is a volcano in the southern hemisphere of Venus at 25 degrees south latitude, 323 degrees east longitude. Its name is derived from vedic goddess of dawn Ushas .The volcano is marked by numerous bright lava flows and a set of north-south trending fractures, many of which appear to have formed after the lavas were erupted onto the surface. In the central summit area, however, younger flows remain unfractured. An impact crater can be seen among the fractures in the upper center of the image. The association of faulting and volcanism is common on this type of volcano on Venus, and is believed to result from a large zone of hot material upwelling from the Venusian mantle, a phenomenon known on Earth as a "hotspot."
The mission
Magellan was launched on May 4, 1989, at 18:46:59 UTC by the National Aeronautics and Space Administration from KSC Launch Complex 39B at the Kennedy Space Center in Florida, aboard Space Shuttle Atlantis during mission STS-30. Once in orbit, the Magellan and its attached Inertial Upper Stage booster were deployed from Atlantis and launched on May 5, 1989 01:06:00 UTC, sending the spacecraft into a Type IV heliocentric orbit where it would circle the Sun 1.5 times, before reaching Venus 15 months later on August 10, 1990.
Originally, the Magellan had been scheduled for launch in 1988 with a trajectory lasting six months. However, due to the Space Shuttle Challenger disaster in 1986, several missions, including Galileo and Magellan, were deferred until shuttle flights resumed in September 1988. Magellan was planned to be launched with a liquid-fueled, Centaur-G upper-stage booster, carried in the cargo bay of the Space Shuttle. However, the entire Centaur-G program was canceled after the Challenger disaster, and the Magellan probe had to be modified to be attached to the less-powerful Inertial Upper Stage. The next best opportunity for launching occurred in October 1989.
Further complicating the launch however, was the launching of the Galileo mission to Jupiter, one that included a fly-by of Venus. Intended for launch in 1986, the pressures to ensure a launch for Galileo in 1989, mixed with a short launch-window necessitating a mid-October launch, resulted in replanning the Magellan mission. Weary of rapid shuttle launches, the decision was made to launch Magellan in May, and into an orbit that would require one year, three months, before encountering Venus.
On August 7, 1990, Magellan encountered Venus and began the orbital insertion maneuver which placed the spacecraft into a three-hour, nine minute, elliptical orbit that brought the spacecraft 295-kilometers from the surface at about 10 degrees North during the periapsis and out to 7762-kilometers during apoapsis
On September 9, 1994, a press release outlined the termination of the Magellan mission. Due to the degradation of the power output from the solar arrays and onboard components, and having completed all objectives successfully, the mission was to end in mid-October. The termination sequence began in late August 1994, with a series of orbital trim maneuvers which lowered the spacecraft into the outermost layers of the Venusian atmosphere to allow the Windmill experiment to begin on September 6, 1994.
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2019 - Wandering Vertexes...
by Francis Rousseau
