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

 Full story »

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

 Full story »

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

 Full story »