With all the excitement about the Rosetta Steins fly-by, it's easy to forget that there is a lot more going on today at ESA! Tonight, at 23:30 CEST - about 2.5 hours after Rosetta makes her closest approach - Jules Verne will undock from the ISS, marking the start of the end of the hugely successful ATV mission. Also today, the GOCE Mission Control Team at ESOC are in a simulation in the Main Control Room for the launch next week, on 10 September, of ESA's gravity satellite. Phew! -- Daniel

It's confirmed the TCM slot that was available 0500-0800 UT this morning was not needed for any final trajectory correction manoeuvre.

After yesterday's TCM (the thrusters ran for 103.5 sec), analysis of Rosetta's location and of the Steins images enabled ESOC Flight Dynamics to determine that Rosetta will pass within 2000m of the targeted 800 km this evening - which is within acceptability for the science observations to come.

It's rare that we in the operations business get to wave our own flag - spacecraft engineers are by nature extremely cautious and restrained folks. "The flight control team, the flight dynamics guys and the science operations team have all made Europe's first optical navigation campaign a huge success," says Flight Director Paolo Ferri.

(Click on 'Full story' for details - updated @ 21:58 CEST). -- Daniel

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After the fly-by which is scheduled for 20:58 CEST ground time today, data will be downloaded through the night. Beginning at 12:00 CEST, there is a press conference here at the European Space Operations Centre. Access live streaming of the press conference on this page.

The stream begins at 11:55 CEST and ends at 13:20 CEST. There is an interesting line-up of talks by some of ESA's top scientists and engineers, who will convey their first impressions of the fly-by, sharing pictures and information transmitted back to Earth the night before. The agenda is available here.

--Amruta

Click on the link below for a very nice visualisation of the Steins flyby.

This comes to us courtesy of our colleagues at DLR (the German Aerospace Center) and Vega; it was created using a simulation tool developed by Vega for DLR, who is responsible for operating Rosetta's Philae lander. It provides a very good (and accurate) visualisation of what you'd see if you were riding on Rosetta tomorrow as she passed Steins - note the size of the asteroid is exaggerated (thanks, Zeina!).-- Daniel

Rosetta Steins flyby visualisation

Steins, a rare E-type asteroid, holds clues on how the planets formed (more info and link to the Podcast after the jump). -- Daniel

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Results from today's trajectory correction manouevre and the navigation image download are now being analysed by ESOC Flight Dynamics. We'll know later whether the last TCM slot tomorrow morning will be used.

Update @ 18:00 CEST - Just got a note from the Rosetta DCR - results from today's analysis show that tonmorrow's final TCM slot may not be needed. More details in the AM. -- Daniel

Today's TCM is now running!

I just had an update from ESA Spacecraft Operations Manager Andrea Accomazzo here at ESOC. He says today's target delta-v (change in velocity) is 11.8 cm/sec in the direction perpendicular to the line of flight. Everything on board the spacecraft is operating nominally, and the results if the TCM will be received (acquisition of signal) starting at 08:56 UT spacecraft time, which is 09:16 UT Earth receive time - which is 11:16 CEST (there's a 20-min one-way signal time at Rosetta's current distance from Earth).

The downlinked telemetry from this pass will include ranging data and more images as part of the still-ongoing optical navigation campaign.

The Flight Dynamics team here at ESOC will asses the results of today's TCM and later this afternoon let the Flight Control team know if the final TCM slot, Friday, just 12 hours prior to closest approach, will be used (click on 'Full story' for more details on today's TCM goals including a chart showing the target plane). -- Daniel

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Steins is one of the rarest types of asteroids in the Solar System and holds clues on how the planets formed.

(2867) Steins vital statistics:

Size                                           4.6 km

Orbital Radius                             353 million km

Class                                         E-type asteroid

Rotation Period                           approximately 6.05 hours

Shape                                        irregular but not elongated

Closest approach                        5 September 2008, 20:58 CEST

Distance at closest approach        800 km

Relative Velocity at fly-by            8.62 km/s

For a detailed description of asteroid Steins, check the Rosetta website: A portrait of asteroid Steins

Background information on asteroids along with a detailed list of previous asteroid fly-bys is here: Debris of the Solar System: Asteriods

--Amruta

I'm now waiting for our scientists to get back to us, and as soon as they do, I'll be posting a (relatively) detailed description of asteroid 2867 Steins. Quite exciting, since it will be only the ninth asteroid to be studied from up close, and very little is known about it and the class it belongs to.

--Amruta

Rosetta's optical navigation campaign has been a first for ESA and is a tremendous success.

If you missed the article published last week in the main ESA web site, the basic info is this: Optical navigation for Rosetta has used the spacecraft's Navigation Cameras (Nav Cams - there are two, 'A' & 'B') and the OSIRIS camera to image Steins (OSIRIS has two science cameras - the Narrow Angle camera has been used for the navigation campaign). These photos are then downloaded and interpreted to generate very precise determinations of Stein's location, and these results are then used to generate the necessary thruster burns to correct the spacecraft's course as it approaches.

On Tuesday, Sabine Kielbassa, on the Flight Dynamics team here at ESOC, sent along two more images with some interesting details. The optical navigation campaign has really shown just how good ESA's Flight Dynamics team are, and she was quick to mention that it's a team effort - together with her colleagues Trevor Morely, Mathias Lauer, and Vicente Companys, all of whom are supported by the extended FD team.

(larger-size images and captions after the jump) -- Daniel

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We've got an expanded version of the Rosetta fly-by timeline that is in the main ESA website. At the time of closest approach (5 Sep 2008 20:58 CEST), Rosetta is planned to be 800 km from the asteroid, passing by at a speed of 8.6 km/s relative to Steins. Both Rosetta and Steins will be illuminated by the Sun, providing an excellent opportunity for scientific observations (full timeline after the jump). -- Daniel

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Clicking about the web this evening, I noticed a few nice links (many in languages other than English) from other bloggers to some of ESA's recent web articles on the upcoming flyby of Steins. You can see lots more via Google or Technorati via the links below. -- Daniel

Technorati

Google blog search

Welcome to the 'new' Rosetta Blog - covering the Steins fly-by on 5 September 2008 (and any subsequent Rosetta activities that we blog about). This new blog was set up - in our new multilingual blog content system - by the excellent ESA tech guys in Frascati, Italy (thanks, Stefan!).

If you are looking for the 'old' (first) Rosetta Blog, which covered the second Earth swing-by in November 2007, you can find it via the link below (there's also a permalink in the right-hand navigation bar). This blog resides in the old content system, and won't be updated any further - but it does include some **excellent** commentary, images and media, so is well worth a quick visit if you are new to the Rosetta family. -- Daniel

Old Rosetta Blog: http://webservices.esa.int/page.php?id=37819