Vesta departure and journey to Ceres, A new phase of Dawn adventure |
Vesta departure and journey to Ceres, A new phase of Dawn adventure |
Aug 26 2012, 05:45 AM
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#1
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
As suggested by "TheAnt", is time to start a new thread!
Due to lack of updates from "Mystic simulator", I asked directly to Marc Rayman for an update and he kindly sent me the following "unofficial" plots, showing evolution of distance, radial velocity and sub-spacecraft latitude (radius trend is splitted in two plots with different scales due to huge variation of the distance): I did not publish them immediately because I wanted to integrate them with my previous plots but, due to the lack of time in last week, I decided to post them directly with only minimal changes. As you can see, third engine stop occurred on Aug 8-18 at almost 2300km above Vesta while next (final) one is just started and, as reported by Marc in his latest journal, will be used to map North polar regions from 6000km distance. Thereafter thrust will resume and, based on plots, on Sept 5 total speed will overcome escape velocity (almost 45 m/s), so total energy balance will be zero; definitive exit from Vesta Hill sphere should occur after 20 days but consider that the times could slighty change due to orbit refinement and thrust plan changes. -------------------- I always think before posting! - Marco -
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Sep 6 2012, 08:42 AM
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#2
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Member Group: Members Posts: 102 Joined: 29-January 10 From: Poland Member No.: 5205 |
Hi
I see some difference in Dawn - Vesta position at Mystic Simulator and Eyes of the Solar System Date and time is 9:43 UTC - 06 Sep 2012 See screens below. What's wrong ? What distance are good ? --------- Added: In HORIZONS JPL is 64 540 km http://ssd.jpl.nasa.gov/horizons.cgi --------- Also in Solar System simulator is 64 549 km http://space.jpl.nasa.gov -------------------- Adam Hurcewicz from Poland
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Sep 6 2012, 10:27 AM
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#3
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
I see some difference in Dawn - Vesta position at Mystic Simulator and Eyes of the Solar System Adam, I can say Mystic is perfectly in line with Marc Rayman plots, as showed in these plots where I merged the two sources: (consider that Mystic hiatus ended yesterday and lasted 1 month; moreover, you will not see distance/velocity modulations due to elliptic orbit during third engine stop because I reported only average info in this period). Moreover, both Marc/Mystic data are in agreement with last Nasa updates about Vesta depart milestone (see links from bellarophon1); in my plots (left/bottom in particular) you can see that total energy becomes positive only on Sptember,5 while, if Dawn really lies at 64500 km from Vesta, this means he surpassed this point many days ago and is already half-way to Vesta Hill sphere margin! -------------------- I always think before posting! - Marco -
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