LAMO, aka Low Altitude Mapping Orbit |
LAMO, aka Low Altitude Mapping Orbit |
Nov 30 2011, 04:18 AM
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#16
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Solar System Cartographer Group: Members Posts: 10231 Joined: 5-April 05 From: Canada Member No.: 227 |
This link...
http://pds-smallbodies.astro.umd.edu/data_...ase_sched.shtml ... suggests a later date. 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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Dec 1 2011, 07:02 AM
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#17
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
This link... suggests a later date. ...and suggests also a new Vesta departure date (shifted from July 2012 to Jan 2013), probably in order to study also North Pole region! -------------------- I always think before posting! - Marco -
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Dec 1 2011, 07:06 AM
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#18
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
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Dec 1 2011, 12:03 PM
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#19
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Member Group: Members Posts: 159 Joined: 4-March 06 Member No.: 694 |
I did a Solar System Simulator run for Vesta and I worked out that equinox for Vesta will be on or about July 27, 2012.
You can work this out by choosing the "from above" viewpoint for Vesta and finding the date when the phase angle is 90 degrees. This is when the sun's terminator is exactly over the North Pole. I got this idea from doing this for Mercury where the phase angle as viewed directly from either pole is always 90 degrees. -------------------- I call heaven and earth to witness against you this day, that I have set before thee life and death, the blessing and the curse; therefore choose life, that thou mayest live, thou and thy seed.
- Opening line from episode 13 of "Cosmos" |
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Dec 1 2011, 03:21 PM
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#20
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
I think shifting the Vesta departure date would require a change to the laws of celestial mechanics--I don't think there's funding for that. :-)
--Greg |
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Dec 1 2011, 03:49 PM
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#21
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Member Group: Members Posts: 656 Joined: 20-April 05 From: League City, Texas Member No.: 285 |
...require a change to the laws of celestial mechanics... I think that with the ion drive, the laws of celestial mechanics allow a bit more leeway than otherwise. That said, I'd rather move on to Ceres sooner rather than later -- that's a much larger and more interesting world. Of course, I'd also like to see real-time data releases :/ |
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Dec 1 2011, 09:01 PM
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#22
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Senior Member Group: Members Posts: 2106 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Yeah, Dawn's launch was delayed three months, but the ion drive gives so much leeway it didn't matter in the end (compared with a conventional launch to Mars for example, that has a very specific window).
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Dec 1 2011, 09:52 PM
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#23
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Senior Member Group: Members Posts: 1592 Joined: 14-October 05 From: Vermont Member No.: 530 |
http://dawn.jpl.nasa.gov/multimedia/vesta_dawn_gallery.asp
Has this new 3D video goodness: http://dawn.jpl.nasa.gov/feature_stories/d..._over_vesta.asp |
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Dec 2 2011, 12:47 AM
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#24
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Senior Member Group: Members Posts: 1592 Joined: 14-October 05 From: Vermont Member No.: 530 |
New Dawn Journal:
QUOTE There is always a tug downward, but because of Vesta's heterogeneous interior structure, the product of its complex geologic history, sometimes there is also a slight force to one side or another. With their knowledge of the gravity field, the team plotted a course that took advantage of these variations to get a free ride. This is akin to experienced sailors not only relying on their ships' engines but also following routes that use known currents to let nature do some of the work. Of course, sailors benefit from knowledge of currents measured by those who plied the waters before them. Dawn is the first, venturing boldly into mysterious seas never visited before. But the measurements of the gravity field in HAMO, even though it was at a higher altitude, gave navigators enough information about what lay ahead on the horizon that our vessel could safely and productively ride the gravitational currents. The flight plan from HAMO to LAMO then is a complex affair of carefully timed thrusting and equally carefully timed coasting. Under ion thrust, the spacecraft flies to a certain location in a certain orbit at a certain time, waits a certain interval as Vesta propels it to the next waypoint, and then it resumes thrusting. Amazing. |
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Dec 2 2011, 06:06 PM
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#25
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Yeah, Dawn's launch was delayed three months, but the ion drive gives so much leeway it didn't matter in the end (compared with a conventional launch to Mars for example, that has a very specific window). Supposedly that delay was running up against the window from Vesta to Ceres, so I suspect there may not be much more leeway to stay at Vesta. Perhaps someone who knows for sure will chime in. --Greg |
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Dec 2 2011, 06:50 PM
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#26
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Member Group: Members Posts: 808 Joined: 10-October 06 From: Maynard Mass USA Member No.: 1241 |
The Dawn Journal and Dr. Marc Rayman should get some sort of award for 'modern science literature'. It is always a fascinating read.
-------------------- CLA CLL
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Dec 3 2011, 06:10 AM
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#27
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
I agree, PDP8E.
-------------------- I always think before posting! - Marco -
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Dec 3 2011, 07:22 PM
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#28
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
After last burns, nominal LAMO height (200km above average radius) was just reached:
However, now orbit needs to become circular... -------------------- I always think before posting! - Marco -
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Dec 4 2011, 09:40 PM
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#29
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
No burns in last hours, orbits is now around 185x245km:
Curiously, most of last burns occurred around apoastron and this reduced periastrum distance only, increasing eccentricity... -------------------- I always think before posting! - Marco -
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Dec 6 2011, 05:53 PM
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#30
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Interesting news via Emily's twitter:
"Russell: pole position for Vesta measured by Dawn differs from astronomically determined value. #AGU11 (1 hour ago)" "Russrll: spring will return to dark north pole later than thought, so they will need to delay Vesta departure in order to image it. #AGU11 (1 hour ago)" -------------------- |
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