Dawn Survey Orbit Phase, First orbital phase |
Dawn Survey Orbit Phase, First orbital phase |
Jul 17 2011, 09:09 AM
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#1
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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 think it's time we start a new thread
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Jul 17 2011, 02:13 PM
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#2
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
Good idea, Paolo!
Dawn's ion engine have been OFF in the last hours (at least 9 hours from my checks) and, as expected, now spacecraft started to accelerate: at current distance, I espect an acceleration toward Vesta of 1,0e-4 m/s2; considering current phase angle, close to 90°, this should cause an increase of total velocity close to 1 mph each 2 hours... until next engines power on! -------------------- I always think before posting! - Marco -
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Jul 17 2011, 02:28 PM
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#3
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Would it be worth renaming the topic to Survey Orbit Phase, given that it is the name that the mission ops team uses for the first orbital phase?
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Jul 17 2011, 03:18 PM
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#4
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
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Jul 17 2011, 06:53 PM
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#5
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
This is an answer to Greg question (from the old thread):
Your question wasn't so silly because helped me to find many answers! You had a nice idea about plotting escape velocity (which depends on distance from Vesta) toghether with speed... this my updated distance/speed plot, zoomed on last weeks: You can clearly see the "capture event", when red curve goes below yellow one (speed axis on the right). Well, as told in the press release nobody knows the exact moment of such event because Vesta mass is only roughly known for the moment (I used 2.69e20Kg value, reported also in Wikypedia; uncertain should be around 2%, which means 1% uncertain in escape velocity). EDIT: meanwhile, Dawn is using again propulsion and speed seems stabilized now... -------------------- I always think before posting! - Marco -
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Jul 18 2011, 05:13 PM
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#6
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
With engines on, Dawn still decelerating, even though at a very slow rate (only 1m/s in last 20 hours) due to Vesta gravity... this is an update of previous plot with a new one (always suggested by Greg) showing speed as a function of distance from Vesta instead of time; I also added a curve showing speed required for circular orbit (pay attention, this is true only if velocity vector is perpendicular to distance vector and this is not the case of Dawn, at this moment!):
-------------------- I always think before posting! - Marco -
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Jul 18 2011, 07:21 PM
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#7
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
OK this is making me absolutely crazy. Another image release (yay!) but as with all the previous image releases the reported scale is wrong. They keep reporting the pixel scale for the original, unenlarged image, and then they post an image that has been enlarged (badly) by some non-integer factor and fail to divide the pixel scale by whatever their enlargement factor was.
-------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Jul 18 2011, 07:37 PM
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#8
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
Hands up, I don't understand all the tech stuff, but I sense your frustration Emily.
Pretty cool view, tho... more and more Mirandan... -------------------- |
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Jul 18 2011, 07:47 PM
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#9
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Solar System Cartographer Group: Members Posts: 10229 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 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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Jul 18 2011, 08:26 PM
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#10
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Junior Member Group: Members Posts: 21 Joined: 4-November 10 Member No.: 5509 |
Wow, stunning image.
While the south polar peak is either impact derived or tectonic, it certainly reminds me of Ayers rock in central Australia. Nice hard hard of rock that says "I am not going anywhere, no matter what you throw at me". Also the ripples around the south polar peak really look like ripples in a pond or maybe just wrinkles from shinkage. |
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Jul 18 2011, 08:31 PM
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#11
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Straight to Planetary Photojournal:
http://photojournal.jpl.nasa.gov/catalog/PIA14313 http://photojournal.jpl.nasa.gov/catalog/PIA14314 (anaglyph!) http://photojournal.jpl.nasa.gov/catalog/PIA14315 http://photojournal.jpl.nasa.gov/catalog/PIA14316 (asteroid size comparison poster) -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Jul 18 2011, 09:03 PM
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#12
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
Thanks for posting those links. Used the tiff file to creare a cleaner view...
http://twitpic.com/5s9axu -------------------- |
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Jul 18 2011, 09:49 PM
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#13
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
That's really nice, Stu!
-------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Jul 18 2011, 10:09 PM
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#14
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Senior Member Group: Moderator Posts: 3242 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
I think I shrunk the original image to something approaching the original resolution. I've also applied a light unsharp mask here:
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Jul 18 2011, 10:14 PM
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#15
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Member Group: Members Posts: 540 Joined: 25-October 05 From: California Member No.: 535 |
Congrats to the Dawn team for a successful orbit insertion! Now looking forward to a color image of Vesta...
-------------------- 2011 JPL Tweetup photos: http://www.rich-parno.com/aa_jpltweetup.html
http://human-spaceflight.blogspot.com |
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