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Cassini-Huygens Mission Status Report - May 28, 2004
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Carolina Martinez (818) 354-9382 Jet Propulsion Laboratory, Pasadena, Calif. Donald Savage (202) 358-1727 NASA Headquarters, Washington News Release: 2004-134 May 28, 2004 Cassini-Huygens Mission Status Report The Cassini spacecraft successfully performed a critical six-minute trajectory correction maneuver May 27 to put it on course with its first encounter, Saturn's outermost moon Phoebe, set for June 11. The spacecraft is operating normally and is in excellent health. "The maneuver is very critical for getting us into Saturn orbit because it is the first checkout of the bipropellant pressurization system after nearly five years of dormancy," said Todd Barber, propulsion engineer for Cassini at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It sets the stage for Saturn orbit insertion on June 30." During the course of its trip, Cassini has traveled 3.4 billion kilometers (2.1 billion miles). "We couldn't have asked for a smoother ride," said Robert T. Mitchell, program manager for the Cassini-Huygens mission at JPL. "All the instruments are performing well, and for almost seven years we have traveled without any major hitches. The excitement is building as we are getting ready to put Cassini in orbit around the ringed planet." The orbiter has relied on three radioisotope thermoelectric generators to power all the electrical components, including the 12 science instruments. The European-built Huygens probe on board Cassini carries six instruments. "If the road to Saturn were a highway, the Cassini orbiter would have passed the sign along the road that says 'Saturnian County line,'" said Jeremy Jones, chief navigator for the Cassini-Huygens mission at JPL. "The next exits are Phoebe, 9 million kilometers (5.4 million miles) ahead, Saturn 19 million kilometers (12 million miles) ahead." Phoebe is an oddly shaped moon with a dark surface. It orbits in the opposite direction from the motion of most other bodies in the solar system. The backwards-revolution leads scientists to believe that it is an object captured from distant Kuiper Belt, making it an interesting target. "The Phoebe flyby may offer the first glimpse of what the frigid bodies at the edge of the solar system look like," said Dr. Bonnie Buratti, scientist on the Cassini-Huygens mission at JPL. "These bodies, which include Pluto and its satellite Charon, are believed to be remnant objects left over from the formation of the planets 4.5 billion years ago." After the Phoebe flyby, Cassini will be on course for Saturn. On arrival date June 30 (July 1 Universal Time), Cassini will become the first orbiter around Saturn. "The two Voyager and Pioneer spacecraft flew by the planet and saw it from a distance two or three days at a time. With Cassini, we will be in the city limits for four years," said Dr. Dennis Matson, project scientist for Cassini at JPL. "The difference is like driving by the Grand Canyon versus stopping, getting off and enjoying the sights for a while." On arrival, Cassini will begin a 96-minute burn designed to put the spacecraft into Saturn's orbit. As part of getting the spacecraft into orbit, Cassini will twice cross between known gaps in the rings. As a precautionary measure, the spacecraft will use its antenna as a shield to protect it from tiny particle hits. A prime target for Cassini and the piggyback Huygens probe built by the European Space Agency is the smoggy moon Titan. "In the 350 years since the discovery of Titan we have come to see it as a world with surprising similarities to our own, yet located almost 1.5 billion kilometers (900 million miles) from the Sun," said Dr. Jonathan Lunine, Huygens interdisciplinary scientist and professor of planetary science and physics at the University of Arizona, Tucson. "With a thick, nitrogen-rich atmosphere and possible hydrocarbon seas, Titan may harbor organic compounds important in the chain of chemistry that led to life on Earth." Six months after reaching Saturn, Cassini will release the wok-shaped Huygens probe towards Titan on Dec. 24, 2004 (Dec. 25 Universal Time). The event will be by far the most distant descent of a robotic probe on another object in the solar system. On Jan. 14, 2005 (Jan. 15 Universal Time), Huygens will enter Titan's atmosphere, deploy its parachute, and begin its scientific observations of Titan. 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, D.C. JPL designed, developed and assembled the Cassini orbiter. For the latest images and more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov . - end - |
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Ron wrote:
"The maneuver is very critical for getting us into Saturn orbit because it is the first checkout of the bipropellant pressurization system after nearly five years of dormancy," said Todd Barber, propulsion engineer for Cassini at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It sets the stage for Saturn orbit insertion on June 30." That's good. So we won't get a replay of that Mars Observer failure. IIRC, Cassini was still being built at the JPL lab when MO blew up just outside of Mars. So the people at JPL could make any changes if needed to avoid that. Looks like the people at JPL did an excellent job designing, building and flying Cassini so far. Looking forward to seeing the pretty pictures and science to be discovered. |
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In article ,
Robert Casey wrote: "The maneuver is very critical for getting us into Saturn orbit because it is the first checkout of the bipropellant pressurization system after nearly five years of dormancy," ... That's good. So we won't get a replay of that Mars Observer failure. Well, *now* we won't. Just before that maneuver would have been the time. IIRC, Cassini was still being built at the JPL lab when MO blew up just outside of Mars. So the people at JPL could make any changes if needed to avoid that. There were a number of changes made, in fact. All titanium pyrovalves were replaced by steel ones, burst disks were added to positively isolate sections of the plumbing until first pressurized, a "pyrovalve ladder"(*) was added to completely separate pressurant and propellants during long periods of idleness, the pressurization system for the main engines was separated completely from that for the ACS thrusters, and a movable shield was added to keep the main-engine system warm when not in use. (* An input line and an output line connected by a bunch of short lines, each with an initially-open pyrovalve and an initially-closed one. Fire the initially-closed one to connect input and output; fire the initially-open one to separate them again. Since pyrovalves are one-shot, the number of times you can do all this is limited by the number of short lines, but if you don't expect to do it often...) -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
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"Ron" wrote in message om... On arrival, Cassini will begin a 96-minute burn designed to put the spacecraft into Saturn's orbit. As part of getting the spacecraft into orbit, Cassini will twice cross between known gaps in the rings. As a precautionary measure, the spacecraft will use its antenna as a shield to protect it from tiny particle hits. Realistically, what protection would the antenna provide? I would have thought that any particle large enought to damage the spacecraft would punch right throught the antenna.... Stupot |
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On Sat, 29 May 2004 08:41:09 GMT, Stuart Chapman wrote:
"Ron" wrote in message om... On arrival, Cassini will begin a 96-minute burn designed to put the spacecraft into Saturn's orbit. As part of getting the spacecraft into orbit, Cassini will twice cross between known gaps in the rings. As a precautionary measure, the spacecraft will use its antenna as a shield to protect it from tiny particle hits. Realistically, what protection would the antenna provide? I would have thought that any particle large enought to damage the spacecraft would punch right throught the antenna.... AFAIK, if there is any significant amount of material in these "gaps", it's most likely in the form of microscopic dust particles which would vaporize on contact with the spacecraft. It's certainly better for the spacecraft to turn an inert piece of material such as an antenna dish than pointing all the sensitive instruments in harm's way. Either way, it's just a precautionary measure and since the high gain antenna dish has a large area, it's practical as a shield. In fact, it's been used as a shield before, during Cassini's traverse of the inner solar system. It acted as a Sun shade, preventing the spacecraft from overheating. -- The butler did it. |
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i'm very excited. when this puppy launched in 1997, i thought 2004
was so far off. no tech failures now! let's get into orbit, and make a good drop (12/04?) to Titan. anything after that is gravy. |
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beavith wrote:
i'm very excited. when this puppy launched in 1997, i thought 2004 was so far off. no tech failures now! let's get into orbit, and make a good drop (12/04?) to Titan. anything after that is gravy. A little later than that. They found a comm link problem with Cassini/ Huygens, that the doppler shift would break that link. So they will release the Huygens probe later, when the speed difference is less. Enough less to not break that comm link. A probe that gathers data but can't send it back doesn't do us any good. |
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On Tue, 01 Jun 2004 20:19:11 GMT, Robert Casey wrote:
They found a comm link problem with Cassini/ Huygens, that the doppler shift would break that link. So they will release the Huygens probe later, when the speed difference is less. Enough less to not break that comm link. A probe that gathers data but can't send it back doesn't do us any good. I've always wondered what the extent of the Doppler shift would be if the original schedule was followed? Is the Cassini receiver really THAT fine tuned to a specific frequency? -- The butler did it. |
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