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Vesta departure and journey to Ceres, A new phase of Dawn adventure
djellison
post Dec 14 2014, 06:43 AM
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QUOTE (Explorer1 @ Dec 13 2014, 11:05 AM) *
Huh, that's a tiny fraction of the tilt of Vesta and Ceres; its even smaller than Mars and Venus.


But it certainly is not 'exactly the same orbital plane as us'
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katodomo
post Dec 14 2014, 10:34 AM
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QUOTE (jgoldader @ Dec 13 2014, 09:48 PM) *
Imagine using a large booster to put dozens of these into the asteroid belt at the same time...

Where they'd die for lack of sun unless you seriously enlarge them to fit some halfway decent panels on them wink.gif
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Paolo
post Dec 14 2014, 10:44 AM
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QUOTE (djellison @ Dec 13 2014, 07:17 PM) *
Changing inclination to 0.76 degrees would require a delta V of about 0.4km/sec


at which heliocentric distance? IIRC, the delta-V for plane change(for a solar orbit) depends on the heliocentri distance
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TheAnt
post Dec 14 2014, 02:51 PM
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QUOTE (Paolo @ Dec 14 2014, 11:44 AM) *
at which heliocentric distance? IIRC, the delta-V for plane change(for a solar orbit) depends on the heliocentri distance


Indeed it does, lets say we are to launch one dedicated mission to study Pallas, the best idea would to launch the spacecraft at an inclined orbit around the Earth of 34.8 from the very start, and then to send it on its way with the upper stage.

So as for expectations, I came to the same conclusion as antipode, without having read the paper in question.
Meaning that with the relatively high daytime temperature I expect Ceres to be a quite flat around the equator, but with a bit more topography, more distinct crater rims etc, toward the poles. And with brighter poles, from hoarfrost that have settled there.
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PDP8E
post Jan 4 2015, 02:00 AM
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While we wait for DAWN to snap more approach images of Ceres, I put the Dec 2014 Framing Camera image (PIA19049) through the deconvolution process. I hate going above 10x on an image, since we are pushing around noise, point spread functions of the camera, and other artifacts (such as working from a JPEG). But I ran this baby up to the max: 30x (!)

Don't try to see craters or such things other than a bright area on the right side (and a slightly darker 'depression' on the lower right --to be named the pdp8e abyss rolleyes.gif ). Most of the image is the deconvolver 'hallucinating' about what it thinks it sees... but it is fun!

The size difference (not resolution) is about what Ceres would appear at roughly 25,000 miles away

Attached Image


--------------------
CLA CLL
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TheAnt
post Jan 4 2015, 10:27 PM
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@PDP8E: Yes it is really to early to see anything on Ceres yet.
But keep it up and in a little over a month we might get to see the first detail.
Hubble images have hinted there is at least one surface feature that could be spotted even at the early approach.

Now craters, if our current thinking is correct Ceres got a dusting of material on top, so larger (and more recent) craters might have a bright bottom.
While I am at it, I am quite pessimistic on the outlook to find any satellite at Ceres for the same reason, any impact that might have sent material into orbit will be mostly be ice and might sublimate before it have time to coalescence, (which might be how the smaller satellites of Pluto came to be in that much colder environment.)
There could be a very small rock in orbit, as for example one component of a binary asteroid that been captured and the small size made it escape detection in telescopic searches.
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katodomo
post Jan 5 2015, 12:42 AM
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"Very small rock" is a relative term - e.g. in this abstract the detection limit mentioned for various searches of Ceres' inner Hill Sphere is somewhere around 1-2 km at 4000 km, possibly bigger further in. And since Ceres' Roche limit even for the most porous of rubble piles is well below 2000 km...
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TheAnt
post Jan 5 2015, 02:29 AM
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Yes "relative" is the word, I were aware of those searches mentioned in the paper and with a size of just one km or two it could be more suitable to name it 'rock' here than Moon which usually make people think of a more substantial object. =)
But yes it could be somewhat larger, especially if it is exceptionally dark.
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mcgyver
post Mar 12 2015, 12:58 PM
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Shouldn't this thread be closed now that Ceres finished its journey?
We are now talking about orbiting Ceres: http://www.unmannedspaceflight.com/index.p...mp;#entry218672
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