The end of MESSENGER's mission, What happens after March 2013? |
The end of MESSENGER's mission, What happens after March 2013? |
May 6 2012, 05:26 PM
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#16
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
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).
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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May 6 2012, 05:30 PM
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#17
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
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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May 6 2012, 05:41 PM
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#18
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
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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May 8 2012, 09:04 PM
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#19
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Member Group: Members Posts: 235 Joined: 2-August 05 Member No.: 451 |
...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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May 8 2012, 09:35 PM
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#20
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
...and if we could find a wardrobe big enough, it could fly to Narnia...
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May 9 2012, 01:19 AM
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#21
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Member Group: Members Posts: 754 Joined: 9-February 07 Member No.: 1700 |
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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May 9 2012, 01:29 AM
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#22
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
There's no soft way of doing it. Indeed, a more eccentric 'lobbed' orbit will involve higher speeds at perigee.
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May 9 2012, 03:41 AM
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#23
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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May 10 2012, 12:49 AM
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#24
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Member Group: Members Posts: 259 Joined: 23-January 05 From: Seattle, WA Member No.: 156 |
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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May 10 2012, 01:58 AM
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#25
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 11 2012, 07:23 AM
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#26
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
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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Oct 11 2012, 05:15 PM
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#27
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
.......................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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Oct 11 2012, 05:48 PM
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#28
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
by the time of impact, solar perturbations will have brought the periapsis latitude back to somewhere around 60°N. so that is where the impact will take place
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