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ESA Rosetta, news, updates and discussion
GravityWaves
post Mar 25 2006, 05:47 PM
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QUOTE (Bob Shaw @ Mar 18 2006, 02:37 PM) *
And earlier still:

February 2007 - Rosetta Mars flyby (200km altitude)

Bob Shaw


I've heard nothing on this Mars flyby mars.gif where does ESA release its press info ?
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Rakhir
post Mar 25 2006, 09:39 PM
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QUOTE (GravityWaves @ Mar 25 2006, 06:47 PM) *
I've heard nothing on this Mars flyby mars.gif where does ESA release its press info ?


Rosetta journey : http://www.esa.int/SPECIALS/Rosetta/ESA38F7708D_0.html
Rosetta factsheet : http://www.esa.int/esaSC/SEMJ09374OD_0_spk.html
Geometry of the flyby : http://www.space.irfu.se/rosetta/sci/mars/
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ljk4-1
post Mar 28 2006, 06:03 PM
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Astrophysics, abstract
astro-ph/0603720

From: Jessica Agarwal [view email]

Date: Mon, 27 Mar 2006 13:00:59 GMT (713kb)

Imaging the Dust Trail and Neckline of 67P/Churyumov-Gerasimenko

Authors: J. Agarwal (1), H. Boehnhardt (2), E. Gruen (1 and 3) ((1) MPI-K Heidelberg, (2) MPS Katlenburg-Lindau, (3) HIGP Honolulu)

Comments: 4 pages, 3 figures, to be published in the proceedings book of the conference "Dust in Planetary Systems 2005"

We report on the results of nearly 10 hours of integration of the dust trail and neckline of comet 67P/Churyumov-Gerasimenko (67P henceforth) using the Wide Field Imager at the ESO/MPG 2.2m telescope in La Silla. The data was obtained in April 2004 when the comet was at a heliocentric distance of 4.7 AU outbound. 67P is the target of the Rosetta spacecraft of the European Space Agency. Studying the trail and neckline can contribute to the quantification of mm-sized dust grains released by the comet. We describe the data reduction and derive lower limits for the surface brightness. In the processed image, the angular separation of trail and neckline is resolved. We do not detect a coma of small, recently emitted grains.

http://arxiv.org/abs/astro-ph/0603720


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Rakhir
post Nov 21 2006, 07:57 AM
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A busy period for Rosetta :
- Honda comet tail observation last July
- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
- Mars flyby in February
- Jupiter observation in April in support of New Horizon

http://sci.esa.int/science-e/www/object/in...fobjectid=40366
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tedstryk
post Nov 21 2006, 12:26 PM
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QUOTE (Rakhir @ Nov 21 2006, 07:57 AM) *
A busy period for Rosetta :
- Honda comet tail observation last July
- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
- Mars flyby in February
- Jupiter observation in April in support of New Horizon

http://sci.esa.int/science-e/www/object/in...fobjectid=40366


I am not sure, but I wonder if we can improve on this shape model. This looks to be a battered relic.



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elakdawalla
post Nov 21 2006, 05:32 PM
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QUOTE (Rakhir @ Nov 20 2006, 11:57 PM) *
- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)

This doesn't give an exact distance but it looks pretty far. Rosetta is currently interior to Mars in its orbit, so it looks like it's around 1 AU away.

From http://neo.jpl.nasa.gov/cgi-bin/db?name=21
Attached thumbnail(s)
Attached Image
 


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IM4
post Nov 21 2006, 07:10 PM
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>Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
approximately 1.62 AU at January 1, 2007 and increasing up to 1.8 AU by the end of the month.

Quite strange moment for imaging, Rosetta will have tens of "encounters" within 0.1 AU while going through inner parts of Main belt after 2007-2008. Of course , it will be rather small asteroids, smaller than giant Lutetia (almost 100 km long), but yet suitable targets for exporation.
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Rakhir
post Nov 21 2006, 09:24 PM
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QUOTE (IM4 @ Nov 21 2006, 10:10 PM) *
Quite strange moment for imaging, Rosetta will have tens of "encounters" within 0.1 AU while going through inner parts of Main belt after 2007-2008.

Rosetta will meet Lutetia again on 10 July 2010 for a close flyby (from a distance of 3000 km).
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mchan
post Nov 22 2006, 04:15 AM
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QUOTE (Rakhir @ Nov 21 2006, 01:24 PM) *
Rosetta will meet Lutetia again on 10 July 2010 for a close flyby (from a distance of 3000 km).

Something to look forward to. The largest asteroid to be encountered to date, and an M-type asteroid which has not been seen close up before. Now if only the ESA folks will kindly post raw images as they receive them...
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Holder of the Tw...
post Nov 22 2006, 05:57 AM
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Does anyone know whether it will be possible to do a mass determination during the Lutetia flyby? Usually these require ultra stable oscillators attached to the transmitters, in order to get a stable enough frequency to track the doppler shift. And you would like to fly as close to your target as possible.

Seeing as how it's an M type, a density measurement, even if it's rough but reasonable (spec. grav +/- 1.5), would be a very useful piece of information.
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edstrick
post Nov 22 2006, 11:43 AM
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a 3000 km flyby is pretty useless for any asteroid mass determination unless the 'oid is something really big, like over 100 km. What's Lutetia's est. diam?
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mchan
post Nov 22 2006, 11:46 AM
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Around 100 km. smile.gif So it's borderline.
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ugordan
post Nov 22 2006, 01:21 PM
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Well, Galileo flybys of Gaspra and Ida were around the same ballpark distance (1600 and 2400 km, respectively) and mass estimates were acquired, probably through two-way doppler before and after the encounter. Rosetta is reaction wheel controlled so in principle it should allow a rough mass estimate to be given in the same way, especially since Lutetia is significantly more massive than the former two so its signature should be much more easily detectable.

EDIT: On second thought, determining Ida's mass was much more straightforward. It has a moon orbiting at a known distance and a known orbital period so mass can be determined to high accuracy. As for Gaspra, the following page has this to say:
QUOTE
Most asteroids are too small to produce noticeable effects on spacecraft. Galileo's 1991 encounter with the asteroid Gaspra produced only images. In 1993, however, Galileo is scheduled to fly by the asteroid Ida, and it is expected that the relatively close approach to Ida will yield the first experimentally measured estimate of an asteroid's mass and therefore density. The corresponding constraints on its composition will allow new insight into theories of the evolution of the solar system and asteroid belt.


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Rakhir
post Nov 29 2006, 09:47 PM
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Rosetta warms up for Mars swing-by
http://www.esa.int/esaCP/SEMNJ8D4VUE_index_0.html

Instruments from both Rosetta orbiter and Philae lander will be used during the observation campaign.
The purpose of the 36-hour observation campaign of 21-Lutetia is to understand the rotation direction of the asteroid.

Rosetta will be able to observe Mars from about 20 hours before it makes its closest approach to about a few weeks after.
Rosetta instruments will be switched off around the eclipse period. However, Philae lander will still be operating and taking measurements during the eclipse as the lander has its own independent power system.
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mchan
post Nov 30 2006, 04:45 AM
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The ESA Rosetta website has a list of the various planetary and asteroid flyby's and their dates, but I did not find a graphic / plot of the trajectory. Is there a figure of the trajectory on ESA (or another public) website that shows the flyby's similar to the figure on the Messenger website for the Messenger mission --

http://messenger.jhuapl.edu/the_mission/trajectory.html
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