Kilometer-High Waves Flow In Saturn's Rings 31
An anonymous reader sends along a Cosmos Magazine piece on the discovery by NASA's Cassini probe of vertical structures in Saturn's rings, 150 times as high as the rings are thick. The structures were seen because a once-every-15-years orientation of the rings caused vertical features to cast visible shadows. "NASA's Cassini probe has uncovered for the first time towering vertical structures in Saturn's otherwise flat rings that are attributable to the gravitational effects of a small moon. 'We thought that this vertical structure was pretty neat when we first saw it in our simulations,' said John Weiss, the paper's lead author at the Cassini Imaging Central Laboratory for Operations in the US city of Boulder, Colorado. 'But it's a million times cooler to have your theory supported by such gorgeous images. It makes you suspect you might be doing something right,' he added." Update: 06/17 19:29 GMT by KD : The CICLOPS team sent a note correcting the attribution of the quote; the linked article also had it wrong, and has since been corrected.
Nice pictures... (Score:5, Informative)
http://ciclops.org/view_event/110/Towering_Edge_Waves_Pop_Into_View
Go take a look. They're great!
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Thanks for the link. I considered submitting the story myself, but it seemed to much self-advertisement.
Re:Nice pictures... (Score:5, Informative)
Oh, an other versions:
Discovery Channel [discovery.com]
Bad Astronomy [discovermagazine.com]
But CICLOPS has the main story. (And should be able to take a reasonable Slashdotting, these days.)
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Re:Nice pictures... (Score:4, Funny)
but not quite as big as the wave of server failures happening right now at cosmosmagazine.com.
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No, but I'd expect Cosmo to do better journalism.
(I'm assuming that the quote that Slashdot has at the end of the summary is straight from Cosmos magazine. It's fairly mangled.)
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The universe made some hairless monkeys to amuse itself.
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Having finally gotten to the Cosmos story, I'm going to repeat my recommendation to head to the source. (Which is almost always a good idea, anyway.) The Cosmos story managed to mangle the quote and you might as well get the original story before the telephone game has taken hold.
I noticed the cowabunga tag on this article. (Score:3, Funny)
When did Michaelangelo start reading Slashdot? Beware if so, fellow Slashdotters; nobody's pizza will be safe!
Resolve the rings (Score:1, Interesting)
Anyone in this audience with actual knowledge of the policies and planning for Cassini missions? If so I some questions.
The primary mission of Cassini ended recently and the extended mission has just begun. Yet only now are we beginning to receive imagery of detailed ring structure. Since the primary mission has ended it is apparent that obtaining detailed images of ring structure was never a priority. All of the time has been spent on the moons, Saturn and relatively wide shots of the rings.
Is resolvin
Re:Resolve the rings (Score:5, Informative)
I am involved with planning the Cassini mission and, in fact, helped plan the images in the current story.
Yet only now are we beginning to receive imagery of detailed ring structure.
You're starting from a mistaken premise. We've been getting detailed images of the rings for the entire mission. In fact, the highest resolution images of the rings to date (probably ever) occurred during orbit insertion at the very beginning of the prime mission.
Since the primary mission has ended it is apparent that obtaining detailed images of ring structure was never a priority.
Nope, rings is a major priority and drives the mission around 20%. (Depending on how you quantify that.)
All of the time has been spent on the moons, Saturn and relatively wide shots of the rings.
Again, blatantly false. Any time we're out of the equatorial plane of Saturn (as we are now and have been many times during the mission to date), we're studying the rings and the magnetosphere (and Saturn, but they tend to be a bit less insistent on this geometry). There are many close-ups of the rings available. Have you looked for them? They're all over at CICLOPS [ciclops.org], if you do a search. Or even browse images, really.
Is resolving the ring constituents even feasible for Cassini?
No, we can't get close enough to resolve a 1-m body.
I can see from the flight schedule that close up passes of some sheppard moons will occur in 2010. Will attempts be made to image the detailed structure of the rings at this time?
Yes and no. At the time of flyby, we're in the ringplane and cannot see the rings very well at all. Near that time, I'm sure we'll take images of the rings. As we have always done.
I know the rings are largely particulate; a fog of ice particles.
Not the main rings, no. The main rings are ~30-cm to ~3-m bodies. And there is almost no way to get close enough to image these. It's not even a matter of risk, it's a matter of having to be far, far too close to what amounts to a solid wall of ring. And what good would imaging a few particles in one location do compared to destroying the spacecraft in the process? Apart from satisfying you need to see even closer up to the rings?
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We have (and will again) flown through the Enceladus plume.
And the spacecraft can't be allowed to die on an orbit that intersects Enceladus's. We don't want to risk contaminating any potential Enceladan environment with terrestrial microbes and plutonium. The End of Mission scenario we're aiming for right now (it hasn't been approved yet) is to plant the spacecraft in the planet. Those last orbits (inside the D ring) will be glorious.
budgets for long lasting missions.... (Score:4, Interesting)
What I notice is that the primary mission has finished and I just bet that the men in suits are circling the project with their budget cutting shears - but then we get new data, stunning imagary and confirmation of old predicitons.
This just goes to show that given the cost of assembling and launching this missions it makes absolute sense to supply funding until the mission carks it. What would of happened if the budgets for the two Mars rovers was removed after the (very short) planned life cycle was finished?
So, does anybody know how long term budgets are assigned, reviewed and extended to cover missions that exceed their predicted life span? I'm kinds interested.
Re:budgets for long lasting missions.... (Score:5, Informative)
We have to apply for extended missions by putting together a plan and pitching what we're going to do. ("More of the same," is generally frowned upon, naturally.) If the mission is healthy and the plan seems reasonable, they'll approve it. From what I've seen (I'm still pretty young in the field), they tend to be pretty favorable to healthy missions, though, so odds seem good of extension. It's pretty much expected that missions will survive their prime missions since those tend to be conservative estimates for life expectancy.
Re:budgets for long lasting missions.... (Score:5, Interesting)
Are the conservative estimates an example of the Scotty factor. In other words if the team is 90% confident that the mission will last 5 months do they then quote 3 to management - that way if they mission carks it after 4 then they are still covered? I would imagine even the scientists and engineers are very concerned about managerial aspect like project tracking and meeting specification now.
More to the point, how do they estimate such a difficult and unpredictable mission parameter anyhow? I mean somethings like battery life, wear and tear and so on must be quite well understood, but others like the stress of launch, damage, and the great "other" option must be much harder to predict.
Re:budgets for long lasting missions.... (Score:5, Interesting)
It's not so much the Scotty factor as standard engineering procedure for years. If you're told to design an elevator to life 5 people, you make sure it can hold 10 just to be safe. If the design requirements from NASA say "Four years", you design for 6 or 8. You don't want to be penalized for early failure, after all.
And I don't know how the engineers estimate life expectancies, but most components aren't mission-enders. You worry mostly about things like fuel/reaction mass and power sources, first. These are relatively predictable. Other parts that fail generally seem to do so gradually. (Electronics degradation, the reaction wheels on Cassini, etc.) So while you wouldn't necessarily have predicted that a priori, you can track it once it starts to happen.
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I imagine they use a lot of data from previous missions with similar equipment. Also backup systems for critical systems. And for the unpredictable- go with the movie "Armageddon"- "You're NASA, don't you just sit around and think shit up?!" I can see a guy in an office with the title "Office of Thinking How Shit Can Go Wrong", and he tries to prevent it. And if there is some plan filed away dealing with Space Dragons, give that dude a medal!
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This is mostly true, at least for flagship missions like Cassini. Almost every system has a full backup. (Except the high-gain antenna, apparently.) The instruments, not so much, but only one of those is mission-critical. (Maybe two, depending how you count things.)
And you know dragons, what can you do?
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I pretty much figured as much from what I've read. I was surprised to read that the wasn't backup in the instruments, but then they take up a whole lot more room than a couple batteries and wiring. And they need surface space to expose themselves. I can see the antenna as it probably takes up a good bit of space to pack away (actually, I have no idea as I'm not an antenna guy, but I figure they have to have some size from that far away).
Space dragons fear space cats, but the catnip always runs out way too
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The high gain antenna on Cassini doesn't pack away, it's a solid dish. (Unlike Galileo, then. Also, this one works...) I'm not 100% certain why they made that design choice (way, way before my time), but it has the benefit of being useful as a shield when they plot through potentially hazardous areas, like dusty rings.
And you don't really back up instruments because no one instrument is really vital to the entire mission. If we lost the ability to do IR spectrascopy, it would be quite a blow, sure. But
Seeing as no one else has said it (Score:1)
Surf's up!!!!!!
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Note a very long post with some excellent images and some interesting thoughts, hope you enjoy reading it more than I did creating it! Enjoy!
I was thinking it! I bet hundreds of others were too! Though others will think us off topic, I would disagree. Imagine!
Whenever I have driven across the USA, in a car, and looked at the hills in the desert, I imagined being the silver surfer [slashdot.org] (home page [slashdot.org]) with that silver hover board of his, slashing across the mountains side walls, especially where there is a ha [slashdot.org]
Weiss is borderline crazy (Score:2, Interesting)
One thing I never understood about him was his compulsion to call 'derivatives'...'potatoes'. Take the potato here. Reverse potato here. The solution is the potato. Coupled with his thick european (swiss maybe?) accent, it made for one of the bigger WTF moments in my college career.
Re:Weiss is borderline crazy (Score:4, Interesting)
Except I've never taught Physics 2 to you or to anyone else.
Although I do love me my potatoes. Maybe you're from the future? Did you bring back stock tips? Or future-potatoes?
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Yeah, I'll stick with the funny version. I suggest you do too.