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The end of MESSENGER's mission, What happens after March 2013?
nprev
post May 6 2012, 05:26 PM
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A 15 nm orbit sounds fascinating, but I wonder if the cameras would be able to capture any imagery that wasn't hopelessly smeared. Sounds as if they'd have to use a high-speed version of Cassini's 'skeet-shoot' technique on preselected targets, and presumably that would require considerable ACS activity (and fuel).


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ugordan
post May 6 2012, 05:30 PM
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Keep in mind MESSENGER's orbital velocity is about an order of magnitude lower than what Cassini was whizzing by Enceladus with and the cameras are also lower resolution.


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djellison
post May 6 2012, 05:41 PM
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QUOTE (Explorer1 @ May 5 2012, 09:24 PM) *
I doubt the camera is even designed to image the sun without being wrecked.


The whole spacecraft isn't designed to point that way - it would cook. The thermal blanket covering one side of the spacecraft is sun pointed at all times to avoid damage to the spacecraft.
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antoniseb
post May 8 2012, 09:04 PM
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QUOTE (JRehling @ Apr 24 2012, 05:56 PM) *
...Going from Earth to the Sun would require more energy than from the Earth to any other object in the universe. (Of course, a cruise from Earth to another galaxy would take a long TIME, but not as much energy as a cruise to the Sun.)...


Not to quibble, and take a seriously off topic tangent, but wouldn't it take a huge amount of energy to escape our galactic orbit? I think we'd need to change velocity about 200 miles/second to get to Sgr A*, which is way more than the mere 19 miles a second for the Earth-Sun trip.

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Stu
post May 8 2012, 09:35 PM
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...and if we could find a wardrobe big enough, it could fly to Narnia...

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brellis
post May 9 2012, 01:19 AM
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It's a bit disappointing to characterize the end of this fantastic mission as more of a skid than a crash, in terms of the photo opportunities. Isn't it possible to lob it into a softer trajectory as the fuel runs out?
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djellison
post May 9 2012, 01:29 AM
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There's no soft way of doing it. Indeed, a more eccentric 'lobbed' orbit will involve higher speeds at perigee.
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Phil Stooke
post May 9 2012, 03:41 AM
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If you come in slower there should be more time to transmit a few last images during the descent, and they'll be sharper - so I'd say it's better to skid than crash. Except it's a crash either way! The one thing I had wondered about was whether the end was expected to be controlled and trackable.

Phil



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Gsnorgathon
post May 10 2012, 12:49 AM
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Does anyone know if any provision is being made to choose the impact site in co-ordination with the BepiColombo mission? They might be able to excavate some compositionally interesting material for BepiColombo to look at.
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Phil Stooke
post May 10 2012, 01:58 AM
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One point about this - there's no fuel left to change the shape of the orbit, and the low point is near the north pole. There might be a small amount of orbital evolution under solar tidal influences, but the chances are the low point will still be very close to the north pole. So that's the only place an impact can occur. It may not be right at the pole, but close to it.

Phil



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Paolo
post Oct 11 2012, 07:23 AM
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I have received a copy of this paper http://www.iafastro.net/iac/paper/id/13288/summary.lite/ which I cannot share.
I have not had the time to read it in detail yet, but there are a couple of things in it that I wanted to share: in November 2013 comet Encke will pass just 3.7 million km from Mercury and MESSENGER could be used to observe it.
the paper also confirms that surface impact is planned for the end of mission. provided budget is available until then, impact could occur in March or April 2015


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TheAnt
post Oct 11 2012, 05:15 PM
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QUOTE (Phil Stooke @ May 10 2012, 03:58 AM) *
.......................So that's the only place an impact can occur. It may not be right at the pole, but close to it.


Too bad that there hardly will be a chance to study any ejecta plume from that impact due to the distance involved. Since Messenger itself have added further information supporting the hypothesis that there might be water ice at the poles of Mercury.
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Paolo
post Oct 11 2012, 05:48 PM
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by the time of impact, solar perturbations will have brought the periapsis latitude back to somewhere around 60N. so that is where the impact will take place


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