# Thread: Rosetta is on its way!

1. Yes it passed earth at about 230000km following rosettas path. It just kept a greater distance when passing earth. The object is expected to drift farther away from rosetta as rosetta continues its journey. Its course was followed back to where rosetta came from when rosetta was taking its last swing by at mars.

2. The first, but rapidly excluded, fear was that it could be some debris from rosetta. Possibly a broken solar panel, the philae lander or the foil rosetta is wrapped in.

4. Nanananana... I got a reply.
I'm out of the office.

5. Originally Posted by Laguna2
Just read on a German news site that rosetta has a companion, possibly an asteroid.
Planetary Society Weblog: Son of Rosetta

On the heels of the news last week that the Rosetta spacecraft was spotted by sky surveys and briefly named among the minor planets as 2007 VN84 came another close approach by a newly discovered near-Earth object, designated 2007 VF189, which had an orbit surprisingly similar to the Rosetta spacecraft, making a close approach to Earth (closer than the Moon, about 250,000 kilometers away) roughly six hours after Rosetta, on November 14.
[...]
In brief: the probability for there to be a random object so close in the sky to Rosetta is 1 in 70; the probability for Rosetta and this object to come close to Earth within 6 hours of each other is 1 in 10; and the probability that they would have velocities within 2.1 km/sec of each other is 1 in 10. Multiplying those together, you get a 1 in 7000 chance for Rosetta and another object to pass so close to each other, at nearly the same speed, near Earth. That's an interesting number, because it's not too likely, but neither is it vanishingly unlikely. Plenty of people bet lots of money on worse odds.

In the end, then, 2007 VF189 is a small, unremarkable Apollo-class object (meaning it's an Earth-orbit-crossing asteroid with an orbital period of longer than one year), and nobody would have paid much attention to it if not for last week's mixup.

6. Thanks 01101001 for the affirmation.
The only source I could find until yesterday night was Spiegel-Online.

So was Rosetta in fact the object that was held as an incoming asteroid or was it all a mixup with 2007 VF189?

7. Originally Posted by Laguna2
So was Rosetta in fact the object that was held as an incoming asteroid or was it all a mixup with 2007 VF189?
From reading it sure seems that 2007 VN84 (AKA Rosetta) was discovered and then shortly later 2007 VF189, independently.

The MPML (Yahoo group mpml · A list for asteroid and comet researcher) probably has the whole tale. I have only sampled a couple of entries.

MPML: Discovery Circumstances of 2007 VF189:

On the night of the 12th (UT) Andrea sent up to me his usual request to
follow up on objects that Alex Gibbs has discovered at 703 the night
before. When this field came up for validation, the original target was
recovered along with the object that is now known as 2007 VF189.
Maybe MPML: A real asteroid chasing the Rosetta probe? will be the most productive of an answer:

After the fuss about 2007 VN84, the online version of the German
weekly "Der Spiegel" now has a story saying that a real asteroid is
chasing Rosetta!
[...]
So I am wondering if all this is maybe just a canard.

8. Rosetta has recrossed Earth orbit and is heading outward. It will reach Mars orbit around the 1st of May.

9. Just a few days short of the 1st of May, actually. Rosetta will cross Mars orbit over the next 12 hours.

Edit: This crossing is simply a milestone in reaching the first point of interest in this mission. On 5 September, Rosetta will sweep past a small asteroid in the Main Belt.
Last edited by Lord Jubjub; 2008-Apr-28 at 02:27 AM.

10. Asteroid Steins

73 days 01 hours

http://www.dmuller.net/rosetta/

11. Originally Posted by Manchurian Taikonaut
Asteroid Steins
ESA: Rosetta awakes from hibernation for asteroid encounter (3 July 2008):

Spacecraft controllers have just awoken Rosetta from hibernation to prepare for its encounter with asteroid (2867) Steins on 5 September. ESA’s comet chaser will study the relatively rare asteroid as it flies by on its way to comet 67/P Churyumov-Gerasimenko.
[...]
In preparation for the fly-by, all the instruments will be checked and tested through the month of July. Between 4 August and 4 September, spacecraft operators will conduct an optical navigation campaign: Steins will be tracked by the on-board cameras and the observations will be used to refine the knowledge of its orbit which has been derived only from ground-based measurements so far.

12. Intense preparations for Rosetta's asteroid visit

http://www.esa.int/SPECIALS/Rosetta/SEM4OCXIPIF_0.html

13. Thank you for the heads up MT!

14. Planetary Society: Planetary News: ESA's Rosetta Has Asteroid Steins in Sight

ESA's flagship solar system mission Rosetta is fast approaching the next waypoint on its long journey to comet 67P/Churyumov-Gerasimenko. On September 5 at 18:37 UTC, the spacecraft will zoom past asteroid (2687) Steins, the spacecraft's first scientific target.

Steins has not before been visited by a spacecraft, so everything that is known about it is based on data from Earthbound telescopes. It is believed to be approximately 5 kilometers in diameter, and it is an E-type asteroid, a rare spectral class.
Lots of stuff. Includes a nice timeline of events September 1 to September 6.

Coming up next:

Sep 1
00:00 Other science instruments switched on
Sep 2
14:30 Trajectory Correction Maneuver
This and the following two maneuvers may be canceled if optical navigation results indicate that the spacecraft is on the proper course for the encounter.

15. Perfect sight: Rosetta cameras track asteroid target

http://www.esa.int/esaCP/SEMC9R6UWJF_index_0.html

16. Sweet

17. Other science instruments have been turned on.

Coming up (times UTC):

• Sep 2
• 14:30 Trajectory Correction Maneuver
This and the following two maneuvers may be canceled if optical navigation results indicate that the spacecraft is on the proper course for the encounter.
• Sep 4
• 05:00 Trajectory Correction Maneuver
• 16:00 End optical navigation campaign
The data must be returned to Earth quickly if the final Trajectory Correction Maneuver is to be performed.
• Sep 5
• 05:00 Trajectory Correction Maneuver
• 08:00 Attempt to put cameras into tracking mode
• 17:57 Begin spacecraft flip
The spacecraft must rotate into a particular orientation in order to track Steins throughout the flyby while also keeping sensitive parts of the Philae lander out of direct solar illumination. The flip takes about 20 minutes to complete; during this time, the cameras should still be tracking the asteroid.
• 18:18 Entry into Asteroid Fly-By Mode
The spacecraft will now perform automatic tracking of the asteroid based upon information from the navigation cameras.
• 18:27 End telemetry from Rosetta
The geometry of the flyby will result in the spacecraft's high-gain antenna pointing away from Earth. Earth will be out of communication with Rosetta for about an hour.
• 18:35 Rosetta views Steins at "zero phase"
Rosetta will pass almost directly between the Sun and Steins, an unusual geometry that provides immensely valuable data on the way that the asteroid's surface reflects sunlight. The entire "globe" of Steins will be fully lit by the Sun.
• 18:37 Asteroid (2687) Steins Closest Approach (800 kilometers)
• 19:37 End Asteroid Fly-By Mode; start high-gain antenna rotation
Control of the spacecraft's orientation will be handed back from the optical navigation system to the spacecraft's internal sequences. At the same time, the high-gain antenna will begin to rotate back towards Earth. The rotation will take 25 minutes to complete. It is possible that the spacecraft will remain out of communication with Earth for 22 of those minutes, until 22:02.
• 20:25 Resume telemetry transmission with Earth
• 21:25 Earliest possible start of scientific data reception on Earth
The first five hours of downlink will contain data from the OSIRIS and VIRTIS instruments. Then two more hours of VIRTIS, followed by data from the rest of the science instruments.
• Sep 6
Edit: New Planetary Society Weblog entry: Rosetta's zeroing in on Steins (September 2)
Last edited by 01101001; 2008-Sep-02 at 06:54 PM.

18. Last edited by 01101001; 2008-Sep-05 at 04:52 AM.

19. ESA: Asteroid (2867) Steins: A portrait

Size 4.6 km
Shape irregular but not elongated
Closest approach 5 September 2008, 20:58 CEST
Distance at closest approach 800 km
[...]
Steins is one of the rarest types of asteroids in the Solar System and holds clues on how the planets formed.

To date, planetary scientists have used various spacecraft to visit eight different asteroids, with six fly-bys and two close orbits. On 5 September 2008, the Rosetta spacecraft will make it nine.
[...]
Called an E-type asteroid, it may once have been part of the outer regions of a much larger asteroid, which has fragmented. Such E-type asteroids are quite rare.

20. Coming soon...

Rosetta fly-by of asteroid Steins: press conference (first results & images)

First results and images from Rosetta's fly-by of asteroid Steins will be presented at a press conference, which will be webcast live, on Saturday 6 September starting at 12:00 CEST [1000 UTC; 0600 EDT; 0300 PDT].

A number of presentations will be made during the press conference covering the Rosetta mission, the challenge of implementing the fly-by, and the first results and images.

21. More Lakdawalla: Planetary Society Weblog: Rosetta's just a day away from Steins and now on target (September 4)

A later update on the blog indicates that this morning's maneuver was successful, and moreover that Rosetta's position may now be close enough to the desired target that the final maneuver slot, planned for tomorrow morning, just half a day before closest approach, might not be needed.

22. 13:58 to closest approach to Steins.

ESA Rosetta Flyby Timeline (times CEST)

Currently 0700 CEST (0500 UTC; 0100 EDT; 2200 PDT).

5 September
07:20-10:20 Slot for possible trajectory correction manoeuvre (12 hours before
closest approach)

10:20 Navigation cameras switch to tracking mode - initially both used,
then use CAM 'A' only (to be decided)

11:00 Uplink fly-by commands for asteroid fly-by mode (AFM)
Includes an update to the command profile already on board & the
final updated AFM commands

20:18-20:38 Spacecraft 'flip over'
20:39 Spacecraft switches automatically to asteroid fly-by mode
20:48 High-gain antenna on hold
From 10 minutes before to about 1 hour after closest approach, the
high-gain antenna will not point to Earth. No telemetry will be received
until the spacecraft exits the asteroid fly-by mode.

20:56 Sun illuminates Rosetta from the back and the asteroid fully
20:58 Closest approach, at a planned distance of 800 km from the asteroid

21:58 Rosetta automatically exits asteroid fly-by mode, high-gain antenna
rotated to Earth pointing (until 22:05)
22:27 First post-fly-by acquisition of signal (AOS) - telemetry received via
NASA's Goldstone ground station
Last edited by 01101001; 2008-Sep-05 at 05:45 AM.

23. ## 3 hours to closest appproach

3 hours to closest approach.

Coming up:

Time is currently 1758 CEST (1558 UTC; 1158 EDT; 0858 PDT).

20:18-20:38 Spacecraft 'flip over'
20:39 Spacecraft switches automatically to asteroid fly-by mode
20:48 High-gain antenna on hold
From 10 minutes before to about 1 hour after closest approach, the
high-gain antenna will not point to Earth. No telemetry will be received
until the spacecraft exits the asteroid fly-by mode.

20:56 Sun illuminates Rosetta from the back and the asteroid fully
20:58 Closest approach, at a planned distance of 800 km from the asteroid

21:58 Rosetta automatically exits asteroid fly-by mode, high-gain antenna
rotated to Earth pointing (until 22:05)
22:27 First post-fly-by acquisition of signal (AOS) - telemetry received via
NASA's Goldstone ground station

There is disparity in the various timelines. Emily Lakdawalla (and dmuller) have closest approach at 18:37 UTC (2037 CEST). The timeline above comes from an ESA Rosetta blog article. I don't know which is more up-to-date. The ESA Rosetta Blog entries show a live countdown clock that has it at 2058 CEST. A offhand comment in a very recent blog entry has it around 2100 (2330 minus 2.5 hours). Anyone who knows, holler.
Last edited by 01101001; 2008-Sep-05 at 06:29 PM.

24. ## 30 minutes to closest approach

30 minutes to closest approach

25. ## Closest approach now

Closest approach now

Check out the press conference tomorrow to see results:

Rosetta fly-by of asteroid Steins: press conference (first results & images)

First results and images from Rosetta's fly-by of asteroid Steins will be presented at a press conference, which will be webcast live, on Saturday 6 September starting at 12:00 CEST [1000 UTC; 0600 EDT; 0300 PDT].

26. ESA Rosetta News: Rosetta Steins fly-by confirmed

The Rosetta control room at ESA’s European Space Operations Centre, ESOC, received the first radio signal after closest approach to asteroid (2867) Steins at 22:14 CEST, confirming a smooth fly-by.

Closest approach took place at 20:58 CEST ground time, 20:38 CEST spacecraft time, at a distance of 800 km. Rosetta’s relative speed with respect to Steins was 8.6 km/sec, or about 31 000 km/h. The exact time of closest approach will be confirmed over the next few days after a detailed analysis of telemetry data.

27. Why do these things never happen durring free period?

28. Well, I guess that I can check that milestone off my long list of events from here to 2015. In exactly one year, this craft will be inside Mars orbit for the final time.

29. Established Member
Join Date
Jan 2007
Posts
336

## Diamond in the sky ...

Esa found a diamond in the sky !
http://www.esa.int/esaSC/index.html

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