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Death of a Spacecraft: The Unknown Fate of Cassini
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Everything I need to know I learned through Googling. |
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I also strongly favor another flyby of Uranus or Neptune, if at all possible.
Some other possibilities: 1.) Wide-angle searches for Saturnian Trojans near the planet's Lagrangian points. 2.) Orbit around Titan to more fully map the moon (though contamination and fuel concerns make this unlikely). 3.) Matching orbits with the rings, such that the relative velocity becomes so low that Cassini could get breathtakingly close to them. 4.) A series of increasingly daring flybys of interesting moons (perhaps a return to Phoebe?), like Iapetus and Enceladus. If the Voyagers are any indication, this probe could be sending back useful data well into the 2020s. It would seem a shame to waste it before it petered out on its own; I'm guessing that in the final analysis, they'll pick something that will make full use of its lifetime potential.
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"He fell for her like his heart was a mob informant and she was the East River." --Anonymous Last edited by Romanus : 08-November-2006 at 09:22 PM. Reason: more stuff |
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All it would take is a solar oribt that intersects the orbit of the target planet in the right place - in fact, if you played your cards right, you could get two flybys. The main concern is the time involved in catching up to the target. You need to arrive at the target with a functioning probe, but that would also be an issue with a KBO mission.
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Uranus and Neptune are on the other side of the Sun from Saturn in 2012, and presumably for some time in the future.
There's also that pesky problem of propellant. Cassini burned a lot of propellant to enter orbit around Saturn. I doubt it has enough propellant today to reach escape velocity. By the time they're getting ready to decommission Cassini, the propellant tanks will probably be just about empty. Cassini burned about half of the propellant load during orbital insertion. It has to burn more propellant every time it changes the orbit to go visit one of the moons. From the Cassini FAQ page: How much longer are you expecting Cassini's batteries to last? Cassini uses nuclear power, so it will have electrical energy available for many years. Propellant used for navigation and orbit control is likely to be the life-limiting resource, and it will last well beyond our prime mission that goes to June 30, 2008. After this, presuming we are approved for an extended mission, the rate of propellant usage depends on the mission profile that is chosen for an extended mission. It could be used up in a year or so, or extended for several years. A mission intensively focused on Saturn's moons -- typically done with targeted flybys -- will use propellant at a much greater rate than simply making magnetospheric measurements. In any event, it is almost certain that electrical power will be available well after we run out of propellant. |
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If they have that much propellant left at 2012, then it seems to me they're flying Cassini way too conservatively. Cassini was built to examine Saturn and its moons. The instruments were optimized for that environment. We spent billions on Cassini. Odds are we won't be sending another major probe to Saturn for a long, long time. We need to make the most of this opportunity. IMO, they should burn the propellant necessary to visit all of Saturns major and most of the minor moons. Once that's completed, boost it to an orbit high enough to avoid contaimination.
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I'd say park it in as stable a Saturn orbit as possible. That way you can sit it there, watching weather patterns until the nuke runs out.
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Quaeso quousque humi defixa tua mens erit? Nonne aspicis, quae in templa veneris? |
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I'd also favor lots of very close (~100 km or less) flybys of moons that were poorly seen during the primary mission, to better refine their masses and densities, and hence give us a vague idea of their internal structure.
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"He fell for her like his heart was a mob informant and she was the East River." --Anonymous |
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I say there is an invisible elf in my backyard. How do you prove that I am wrong? Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability. The Leif Ericson Cruiser |
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Park it in the Cassini Division I say.
What a view! I would very much like to see the rings up really, really close, once you can make out individual ring particles, all individually reflecting/refracting sunlight (aren't they mainly ice?) but slowly changing their releative sun angles across vast distances, the perspectives from within the rings could yield some truely mindblowing vistas. |