janehoustonjones
sage
Reged: 10/21/07
Posts: 240
Loc: 34 N 118 W, 637.0 feet
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This great news just released by NASA and ESA. Cassini's 4 year prime mission has been extended for two more years.
NASA Extends Cassini's Grand Tour of Saturn
April 15, 2008
(Source: NASA/JPL)
Excerpt:
PASADENA, Calif. -- NASA is extending the international Cassini-Huygens mission by two years. The historic spacecraft's stunning discoveries and images have revolutionized our knowledge of Saturn and its moons.
Cassini's mission originally had been scheduled to end in July 2008. The newly-announced two-year extension will include 60 additional orbits of Saturn and more flybys of its exotic moons. These will include 26 flybys of Titan, seven of Enceladus, and one each of Dione, Rhea and Helene. The extension also includes studies of Saturn's rings, its complex magnetosphere, and the planet itself.
Click on the link http://saturn.jpl.nasa.gov/home/index.cfm
for the full press release, a related video about the Casssini tour designers, and podcast featuring an interview with Cassini Progam manager Bob Mitchell about the extended mission.
Jane
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Jane Houston Jones
Cassini Program Outreach Office
JPL's What's Up Podcast is here!
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10022
Loc: Chaville, France
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 two more years! two more years!
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Matt
CI700 mount with various scopes on top.
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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Jane, you beat me to it. WooHoo!!!!
One step closer to keeping Cassini operating out to Saturn's solstice.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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imjeffp
Senior Space Cadet
Reged: 09/30/03
Posts: 4427
Loc: Cedar Park, Texas
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What I don't get is that after all the money, time & effort involved in getting the spacecraft in Saturnian orbit, you'd just throw the switch and walk away from a functioning spacecraft?
Are there other organizations, maybe universities, that would pick up a program if it were dropped by NASA?
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Blog
ST80 • AT80EDT/LXD650
ETX-90/DS-2000 • 10" LX200 Classic ("The Quarter-Meter Telescope at the Heritage Park Observatory")
SPC900NC • DMK21AF04 • Digital Rebel XT
  
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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Quote:
What I don't get is that after all the money, time & effort involved in getting the spacecraft in Saturnian orbit, you'd just throw the switch and walk away from a functioning spacecraft?
Are there other organizations, maybe universities, that would pick up a program if it were dropped by NASA?
I really hope this thread does not get political. However, it is all a competition for resources (mostly money and time). NASA could only do a finite number of things with the money given to it. Not only are scientists are divided on which bodies warrant the money for study (e.g. Mars vs. outer planets), but there are the political pressures to develop a space shuttle replacement and to go to the Moon and Mars.
I doubt if a single university has the resources to keep Cassini operating (you're talking a keep a staff of several hundred engineers and funding scientists to do the research, not to mention developing the infrastructure to do so). A company won't do it because there is no profit in it for them. The European Space Agency probably could do so, but there are many issues with giving away our technology.
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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imjeffp
Senior Space Cadet
Reged: 09/30/03
Posts: 4427
Loc: Cedar Park, Texas
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I understand large numbers of people required to develop the mission, but once the spacecraft is orbiting the planet, how many people does it take to simply receive the data? It's not like there's a slot on the side of the spacecraft that you have to keep feeding $20 bills into to keep the camera turned on and the radio transmitting.
(I'm not arguing--I really don't know what the requirements are.)
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Blog
ST80 • AT80EDT/LXD650
ETX-90/DS-2000 • 10" LX200 Classic ("The Quarter-Meter Telescope at the Heritage Park Observatory")
SPC900NC • DMK21AF04 • Digital Rebel XT
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 10475
Loc: Amargosa Valley, NV, USA
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Quote:
It's not like there's a slot on the side of the spacecraft that you have to keep feeding $20 bills into to keep the camera turned on and the radio transmitting.
I hear that addition is contemplated for future missions.
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"S.O.E." (Sauron's Other Eye) 16" Royce conical mirror: A permanent work in progress.
10" Homebuilt dob, old Coulter mirror
Next Project: The "Eye of Sauron" Observatory!
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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Quote:
I understand large numbers of people required to develop the mission, but once the spacecraft is orbiting the planet, how many people does it take to simply receive the data? It's not like there's a slot on the side of the spacecraft that you have to keep feeding $20 bills into to keep the camera turned on and the radio transmitting.
(I'm not arguing--I really don't know what the requirements are.)
It literally takes a cast of hundreds. There are folk who need to monitor the spacecraft daily, folk to negotiate the science to be done over the next 6 months, folk to turn those negotiations into commands for the spacecraft, folk to uplink those commands, folk to retrieve the days worth of data, scientists to look at the data and determine what is next. Not to mention all of the administrative support required.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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Pess
(Title)
Reged: 09/12/07
Posts: 1910
Loc: Toledo, Ohio
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Quote:
I understand large numbers of people required to develop the mission, but once the spacecraft is orbiting the planet, how many people does it take to simply receive the data? It's not like there's a slot on the side of the spacecraft that you have to keep feeding $20 bills into to keep the camera turned on and the radio transmitting.
(I'm not arguing--I really don't know what the requirements are.)
Do a Google search. You'd be amazed at how many spacecraft have been lost due to a simple command or software error. You need a quality staff to backstop this stuff.
You get the antenna pointed in the wrong orientation because the craft thinks Earth is here instead of there and you can say goodbye to a perfectly good spacecraft.
Pesse (The Viking 1 Lander was lost in this manner.) Mist
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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What folk have to remember is that spacecraft like Cassini and Galileo are not autonomous. They are multipurpose and what they do is very dependent on the changing geometry (determined both by the science objectives and frequent encounters with satellites). Similar reasons apply to the Mars rovers.
Earth orbiting satellites are a little simpler to operate because they have fewer tasks that are repeated over and over again.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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Rick Woods
Post Laureate
Reged: 01/27/05
Posts: 4301
Loc: Inner Solar System
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Yeah, but it seems like the lion's share of the money has already been spent getting it there. It would be nuts to save the pennies and cut the dollars loose.
And NASA just proved that it's not nuts! So we don't need to get political at all - just give a big woohoo! to NASA. They seem to end up making the right (to me) decisions - extending Cassini, saving Hubble, not shutting down Spirit, etc.
There was talk a couple of years back about pulling the plug on Voyager. They didn't end up doing that either, did they?
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- Rick
14" LX200GPS
8" Meade 826C
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 10475
Loc: Amargosa Valley, NV, USA
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Considering the tightness of the budget, and the pressure to get new missions off, I am always grateful that NASA has enough collective wisdom somewhere in its bureaucracy to reserve a bit of funding for the continuation of successful and productive missions.
I don't like the fact that exciting new missions might have to be delayed, downscaled or canceled as a result, but I recognize that it's a reality that can't be helped in the current environment.
I'm also wildly wow'd at just how reliable and productive these recent missions have turned out to be. I don't know if it's just a spate of good luck, or that the engineering challenges have finally been met with the proper expertise, but to see the longevity of the Mars rovers and of Cassini, along with the other successful and repurposed missions (such as Deep Impact) makes me proud to be involved, even if only as a supporting taxpayer.
Keep up the good work, gu's!   
Not to be political, but when I achieve my goal of World Domination as Unquestioned Totalitarian Dictator, the good folks at NASA and JPL have an excellent chance of getting through the first few purges unscathed.
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"S.O.E." (Sauron's Other Eye) 16" Royce conical mirror: A permanent work in progress.
10" Homebuilt dob, old Coulter mirror
Next Project: The "Eye of Sauron" Observatory!
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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Quote:
Not to be political, but when I achieve my goal of World Domination as Unquestioned Totalitarian Dictator, the good folks at NASA and JPL have an excellent chance of getting through the first few purges unscathed.
Vote Dave for Unquestioned Totalitarian Dictator!!! 
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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LadyAstronomer
Bookworm
Reged: 11/15/07
Posts: 2951
Loc: Library of Congress
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Quote:
Quote:
I understand large numbers of people required to develop the mission, but once the spacecraft is orbiting the planet, how many people does it take to simply receive the data? It's not like there's a slot on the side of the spacecraft that you have to keep feeding $20 bills into to keep the camera turned on and the radio transmitting.
(I'm not arguing--I really don't know what the requirements are.)
It literally takes a cast of hundreds. There are folk who need to monitor the spacecraft daily, folk to negotiate the science to be done over the next 6 months, folk to turn those negotiations into commands for the spacecraft, folk to uplink those commands, folk to retrieve the days worth of data, scientists to look at the data and determine what is next. Not to mention all of the administrative support required.
-S
I would also add that along with the "folks who monitor the spacecraft," there are folks who monitor and maintain individual instruments on board the spacecraft. Each instrument has its own team keeping it in working order. It is a coordinated effort between the mission operations center and individual science operations centers (SOC). SOCs are often located at universities, but their personal are funded, in part, by a given NASA mission/program budget. My current position falls under such an umbrella.
Quote:
Not to be political, but when I achieve my goal of World Domination as Unquestioned Totalitarian Dictator, the good folks at NASA and JPL have an excellent chance of getting through the first few purges unscathed.
Dave, please don't forget those of us affiliated with universities!! 
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"I do not know what I may appear to the world, but to myself I seem to have been only a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." -- Sir Isaac Newton
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Rick Woods
Post Laureate
Reged: 01/27/05
Posts: 4301
Loc: Inner Solar System
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Quote:
Considering the tightness of the budget, and the pressure to get new missions off, I am always grateful that NASA has enough collective wisdom somewhere in its bureaucracy to reserve a bit of funding for the continuation of successful and productive missions.
I don't like the fact that exciting new missions might have to be delayed, downscaled or canceled as a result, but I recognize that it's a reality that can't be helped in the current environment.
I would venture that continuation of successful missions is one of the primary purposes of their budget (in theory), and that those expenditures are not what result in the cancellation of new missions.
The things that DO result in those delays/cancellations are external to NASA, and beyond their control. They're in an impossible position, and it's a shame in every sense of the word that they have to make such decisions. Build the ISS; Send men to the Moon and Mars; Develop a Shuttle replacement; (And, oh yes, no additional funding).
Ya gotta love 'em for being able to get anything done at all!
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- Rick
14" LX200GPS
8" Meade 826C
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10022
Loc: Chaville, France
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Quote:
What folk have to remember is that spacecraft like Cassini and Galileo are not autonomous. They are multipurpose and what they do is very dependent on the changing geometry (determined both by the science objectives and frequent encounters with satellites). Similar reasons apply to the Mars rovers.
Earth orbiting satellites are a little simpler to operate because they have fewer tasks that are repeated over and over again.
-S
Quick follow-up question - when SL9 ran into Jupiter 14 years ago, we were fortunate to have Galileo on site to have a ringside view. With Cassini (or any other craft), to what extent would it be possible to "hibernate" the craft until there is some time-critical science to be done (major atmospheric phenomenon, comet close encounter or crash, "stereo" observations with another deep-space probe, what not)? I believe that the nuclear power generator on board has a finite shelf life and that it keeps on generating whether the power is used or not, and that you may have to keep the craft ready to receive instructions from Earth, but would it be possible?
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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The orbit of Cassini is complicated and requires frequent flybys with Titan to steer it to the next target. That said, each flyby is a net loss of fuel (hydrazine) because one must target Titan and make minor corrections after the flyby. There is no orbit in which we can "park" it until we are ready to use it again. Even if there was such an orbit, it would most likely use up all of our fuel to get there (it would have to be far enough from the satellites to minimize their gravitations tug).
On power, we can go quite a while. However, the longer we go, it becomes more difficult to keep all of the instruments powered at the same time.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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LadyAstronomer makes an excellent point. Counting the instrument teams, the cast is much larger.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10022
Loc: Chaville, France
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Quote:
.. There is no orbit in which we can "park" it until we are ready to use it again. -S
So if we just decided to stop making course corrections right now, the craft would end up smashing on Titan or be ejected from the system?
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jupiterzkool
Pooh-Bah
Reged: 05/08/06
Posts: 1341
Loc: Pasadena, CA
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Quote:
Quote:
.. There is no orbit in which we can "park" it until we are ready to use it again. -S
So if we just decided to stop making course corrections right now, the craft would end up smashing on Titan or be ejected from the system?
To "park" it, we would need to use a significant amount of the remaining fuel to ensure that it is in an orbit where nothing in the system is hit.
If we just stopped controlling it now and we were not on a Titan impacting trajectory, eventually (anywhere from years to decades to centuries), it would smash into some object in the system. Otherwise, Titan will be hit the next time around.
It would take much of the remaining fuel to eject it from the system.
-S
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Scott G. Edgington, Planetary Scientist
Cassini-Huygens: Mission to Saturn & Titan
Yes, Asia, John Wetton Fan
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