Posted: Friday, June 4, 2004
In just under four weeks, the Cassini spacecraft will end a seven-year trek across the solar system when its main engine fires and it slips into orbit around the planet Saturn. On the evening of June 30, 2004, PDT, just 25 minutes before the main engine ignites, and 52 minutes before the spacecraft makes its closest approach to the planet, Cassini will pass from its southerly approach to Saturn into the northern hemisphere by crossing the planet's ring plane at a distance of about 19,000 km outside the F ring.
Images released today by the Cassini Imaging Team indicate Cassini's present view of Saturn, in color and looming up ahead, as well as the position of Cassini's ring plane crossing relative to Saturn's rings and some of its moons. This location was chosen to minimize any danger to the spacecraft from orbiting debris.
'After all this time, it's a real thrill to see where Cassini will be in only a few weeks', said Carolyn Porco, leader of the Cassini imaging team and director of the Cassini Imaging Central Laboratory for Operations in Boulder, Colorado.
The spacecraft will fire its main engine for 96 minutes during the critical Saturn Orbit Insertion (SOI) maneuver. The maneuver will reduce Cassini's speed, so Saturn can capture it as an orbiting satellite. Cassini will pass through a gap between the planet's F and G rings, swing close to the planet, and begin the first of 76 orbits around Saturn's system.
There are risks involved with the SOI maneuver, but mission planners have prepared for them. There is a backup in case the main engine fails, and the path through the ring plane was searched for hazards with the best Earth and space-based telescopes, including the Cassini cameras. Particles too small to be seen from Earth could be fatal to the spacecraft, so Cassini will turn to use its high gain antenna as a shield against small objects.
Science planning engineer and associate of the imaging team, Kevin Grazier of the Jet Propulsion Laboratory said, 'I'm not worried about SOI because the spacecraft engineers and mission designers have worked it, and worked it, and re-worked it and as a result, everybody is very confident that by the end of the burn, we'll be in orbit.'
The Cassini/Huygens mission is a four-year study of Saturn. The 18 highly sophisticated science instruments will study Saturn's rings, icy satellites, magnetosphere, and Titan, the planet's largest moon. Hundreds of thousands of images of Saturn and its rings and moons are expected over the course of the mission. The highest resolution images of Saturn's rings during the whole orbital tour will be taken after the orbit insertion burn, when the spacecraft is less than 16,000 kilometers above the rings.
'Cassini has been functioning so well for so many years now, and so much effort has been put into making these critical events -- ring plane crossing and orbit insertion -- as safe as possible', said Porco,`that I have no trepidations whatsoever about the outcome of events on the evening of June 30. I am far more anxious about keeping up with the flow of events and images once we're in orbit!'
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington. The imaging team is based at the Space Science Institute, Boulder, Colo.
The Space Science Institute is a non-profit organization of scientists and educators engaged in research in the areas of astrophysics, planetary science and the earth sciences, and in integrating research with education and public outreach.
The new images can be found at the Imaging Team's website on Thursday, June 3, 2004 at 8:00 a.m. MDT:
Additional information on the Cassini-Huygens mission can be found at:
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