http://www.msnbc.msn.com/id/5333700/Cassini probe enters orbit around Saturn
Spacecraft settles in between planet's famous rings
By John Antczak
The Associated Press
Updated: 12:13 a.m. ET July 01, 2004PASADENA, Calif. - The international Cassini spacecraft threaded a gap between two of Saturn?s dazzling rings late Wednesday and entered orbit around the giant planet, completing one of the mission?s most critical maneuvers more than 900 million miles from Earth.
Mission control at NASA?s Jet Propulsion Laboratory erupted in cheers shortly before 9 p.m. when a radio signal indicated Cassini had been captured by Saturn. Less than 15 minutes later, confirmation came that Cassini's engine burn had completed.
Propulsion engineer and mission commentator Todd Barber said the announcements came earlier than predicted because the signal had been tracked so well.
The maneuver, which brought Cassini within 12,500 miles of Saturn?s cloud tops, came after two decades of work by scientists in 18 nations.
The craft could have simply flown past Saturn if the burn failed to brake its acceleration properly.
The $3.3 billion mission, funded by U.S. and European space agencies, was designed to give scientists at least a four-year tour of Saturn and some of its 31 known moons. Cassini is scheduled to make 76 orbits and repeated fly-bys of the moons.
Scientists hope the mission will provide important clues about how the planets formed. Saturn, the sixth planet from the sun and the second-largest, intrigues scientists because it is like a model of the early solar system, when the sun was surrounded by a disk of gas and dust.
Cassini has traveled 2.2 billion miles since it was launched in 1997, getting gravitational assists from Earth and Venus as it caromed around the solar system.
The spacecraft took the roundabout route because the 22-foot-long, 13-foot-wide craft was too massive to be launched on a direct trajectory to Saturn.
Cassini also carried with it a probe ? named Huygens ? to be sent into the atmosphere of Saturn?s big moon Titan in January. The moon, blanketed by a thick atmosphere of nitrogen and methane, is believed to have organic compounds resembling those on Earth billions of years before life appeared.
Navigation team chief Jeremy Jones said Cassini would reach speeds of up to 68,700 mph Wednesday as it was drawn into Saturn?s gravity. Cassini was programmed to ascend through a gap between two of Saturn?s rings, fire its rocket for 96 minutes to slow down and then settle into orbit.
Cassini and its probe are named for 17th-century astronomers Jean Dominique Cassini and Christiaan Huygens.
Previous expeditions to Saturn were brief. There were fly-bys by Pioneer 11 and the Voyager missions from 1979 to 1981.
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Here's hoping for a successful mission! Looking forward to the Huygens probe in six-and-a-half months!
Topic: Cassini Probe Enters Saturn Orbit! (Read 3523 times)