Ceres Low-Altitude Mapping Orbit (LAMO) |
Ceres Low-Altitude Mapping Orbit (LAMO) |
Apr 23 2016, 02:25 PM
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#181
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Senior Member Group: Members Posts: 4246 Joined: 17-January 05 Member No.: 152 |
Seems that there really is a serious proposal for a mission extension to visit another asteroid. To be fair, that just refers to the original New Scientist story. It would be good to get independent confirmation, though NS is usually reliable in these matters. I wonder how hard it would be for someone here to work out the delta v's for some potential new flyby targets. Do we have an estimate of the remaining delta v? Is there some minimal science that could be done in flyby? |
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Apr 23 2016, 03:44 PM
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#182
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Junior Member Group: Members Posts: 61 Joined: 20-March 10 From: Western Australia Member No.: 5275 |
I think we should squeeze as much data from Ceres as the mission allows.
SF has always viewed Ceres as a staging post between the inner and outer Solar System. Initial results (brine/subsurface H2O) makes Ceres appear as a nice, some may say, balmy stop over. |
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Guest_Steve5304_* |
Apr 23 2016, 05:08 PM
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#183
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Guests |
Why cant we just go an even lower descent on Ceres. Or are we not calibrated for that?
A new target does not make a lot of sense imo, it wont be anything bigger than a few football fields unless there is something i am missing |
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Apr 23 2016, 05:31 PM
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#184
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
To be fair, that just refers to the original New Scientist story. It would be good to get independent confirmation, though NS is usually reliable in these matters. I wonder how hard it would be for someone here to work out the delta v's for some potential new flyby targets. Do we have an estimate of the remaining delta v? Is there some minimal science that could be done in flyby? Eh, rough numbers - Dawn 425kg of xenon, and delta-v of 1000m/s uses about 25kg of xenon. http://dawn.jpl.nasa.gov/mission/popups/faq_qa_M3.asp Planned to use about ~275kg to get to vesta and then ~110kg to get to Ceres and spiral down to orbit. Estimates were ~40kg of xenon would be left at the end of the Ceres orbit, that would be 1,600m/s. Estimates for escape velocity from ceres low orbit, googling suggest around 400m/s. Interesting, so Dawn might have enough xenon to break ceres orbit and still have over 1,000m/s of thrust left. |
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Apr 23 2016, 06:29 PM
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#185
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Senior Member Group: Members Posts: 2511 Joined: 13-September 05 Member No.: 497 |
I'm betting on Pallas in 2018-2019. Pallas is too inclined to the ecliptic to reach. From http://dawn.jpl.nasa.gov/mission/faqs.asp, Marc Rayman says QUOTE Pallas is highly inclined to the ecliptic plane. A lot of energy is needed to climb out of the ecliptic plane especially as far out of the plane as Pallas is. I DID try to design a mission to reach Pallas and it was impossible with the Dawn spacecraft even if we went nowhere else than Pallas. BTW, you can't do effective gravity assists from small bodies. See "Tethers and asteroids for artificial gravity assist in the solar system", http://arc.aiaa.org/doi/abs/10.2514/3.25086?journalCode=jsr -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Apr 23 2016, 07:31 PM
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#186
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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 |
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Apr 23 2016, 08:16 PM
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#187
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
for orbiting no doubt, but you can fly by it when it cuts through Dawn's orbital plane Yep, which is why I said 2019; that's (roughly) when Pallas crosses the ecliptic plane. -edit- actually Pallas crosses in 2017 and 2019... And 2019 also happens to be when Pallas comes closest to Ceres. It will be interesting to see whether the choice of words is significant, e.g. "visit another asteroid" versus "orbit another asteroid" |
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Apr 23 2016, 08:37 PM
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#188
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Really can't see this as being anything other than a flyby, and with a limited chance of success at that given the age and health of the spacecraft. In fact, I would characterize it as a sort of enhanced end-of-mission disposal plan. Main goal does seem to be ensuring that Dawn doesn't impact Ceres and thus violate the planetary protection protocols.
NOTE: If this becomes confirmed as a real thing we'll split it off as its own thread. Main focus here will continue to be LAMO operations, of course. -------------------- 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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Apr 29 2016, 05:18 AM
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#189
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Member Group: Members Posts: 890 Joined: 18-November 08 Member No.: 4489 |
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May 4 2016, 03:48 PM
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#190
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Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
New LAMO Index map to LO-79 and a montage of Messor caldera (LO-1 + LO-77).
https://univ.smugmug.com/Dawn-Mission/Ceres-LAMO-Images/ --Bill -------------------- |
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May 4 2016, 07:24 PM
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#191
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Senior Member Group: Members Posts: 2082 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Interesting quote from this month's journal entry:
QUOTE In an upcoming Dawn Journal, we will discuss how the last of the dwindling supply of hydrazine may be used for further discoveries. Not ruling anything out apparently... |
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Jun 6 2016, 10:43 PM
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#192
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Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
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Jun 17 2016, 03:25 AM
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#193
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Member Group: Members Posts: 890 Joined: 18-November 08 Member No.: 4489 |
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Jun 22 2016, 09:39 PM
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#194
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Solar System Cartographer Group: Members Posts: 10153 Joined: 5-April 05 From: Canada Member No.: 227 |
-------------------- ... 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 PD: 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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Jun 23 2016, 03:02 AM
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#195
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Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
crossed with the other composite image it's hard to get a good result despite attempts to adjust for lighting differences.. but there is an intriguing morsel of relief in the main crater..
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