I've been in contact with astronomer Andy Rivkin, from the Johns Hopkins University Applied Physics Laboratory, in Maryland, USA. He was in the news recently as the leader of one of two teams that found ice and organic material on the asteroid Themis. That discovery was made with the same telescope Andy had used to study Lutetia almost 15 years earlier. So this flyby has a special meaning.

We really don't know what to expect from Lutetia, which is exciting..

-- Andy Rivkin

He agreed to answer some questions via mail - access details under 'Full story' -- Stuart

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Live webcam picture of ESA's 35m DSA at Cebreros, Spain, now tracking Rosetta. Image refreshes every minute; click for full-size version here. Note: webcam timestamp is off by one hour - we'll update it shortly.

This just in from Richard Moissl, working on the OSIRIS team at the Max Planck Institute for Solar System Research here in Germany. Richard writes: "Since 6:18 UTC (08:18 CEST), Osiris has been imaging the approach with both cameras, the narrow angle camera (NAC) and the wide angle camera (WAC), collecting images with 10-minute intervals."

The OSIRIS team will keep us updated (and we'll pass along info right here in the blog) - and we are looking forward to seeing the results of their work later today! A quick reminder: one of the unavoidable limitations to publishing images will be download slots. -- Daniel

Welcome to this exciting day for Rosetta! Later today, the spacecraft will fly by the mysterious asteroid Lutetia. For those scientists who worked on ESA’s Giotto mission, there is a sense of déjà vu. Eighteen years ago to the very day, Giotto flew past the comet Grigg-Skjellerup.

It was a hot summer night in ESOC, Darmstadt, Germany, in 1992 when Giotto slipped past comet Grigg-Skjellerup at a distance of just 200 km.  A forerunner of ESA’s Rosetta mission, Giotto had performed a spectacular flyby of Halley’s comet in 1986. It then went on to an extended mission because, although damaged by the Halley encounter, which saw dust smashing into the spacecraft at speeds of almost 70 km/s, it still had 60 kg of fuel left on board.

Click to watch video: 20 Years after Giotto
Twenty years ago, in 1986, Comet Halley had its latest
rendezvous with the Sun and spectators here on Earth.
Only months before, ESA had launched its first deep-space
mission - Giotto. Its destination, Comet Halley.

The comet chosen was Grigg-Skjellerup and the encounter distance was much closer, too. This was possible by although Giotto tore past Halley ‘head-on’, obtaining its last image at a distance of 6500km, it would only coast through Grigg-Skjellerup’s path at a more oblique angle. Also, the second comet was much less active at producing dust than Halley.

During the pass, Giotto's Energetic Particle Detector (EPONA) captured data that suggested Grigg-Skjellerup had broken in two but the spacecraft captured no images to look for the fragment: the camera had been ‘sandblasted’ to destruction during the Halley flyby. The collision of a single dust particle in 1986 had set Giotto spinning, exposing the instruments to the torrent of comet dust. As a result, the camera was damaged beyond resuscitation. Today, Rosetta will return images. Its target is an asteroid, not a comet, and so it does not make so much dust. The cameras are all working and the first pictures are expected to be released at 23:00 CEST tonight. Stay tuned! -- Stuart Clark

Yesterday evening, Jennifer Ouellette at Discovery News had a fabulous take on the blossoming relationship between Rosetta and Lutetia:

"So here's a word of advice to Rosetta: dude, move on to the next asteroid already, or better yet, save yourself for your intended comet. Because Lutetia is a little out of your league. And frankly, she's just not that into you."

Check out a great online count-down site for Rosetta's flyby of Lutetia at Daniel Mueller's site here.

  CREDIT: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

The OSIRIS imaging team have just sent in an image! Modest, yes, but the target's in sight! :-)

It shows asteroid 21 Lutetia from a distance of 2 million km, rapidly decreasing, and was acquired by the Narrow Angle Camera of the OSIRIS imaging system on board ESA's Rosetta spacecraft on 9 July 2010 at around 03:00 CEST. Rosetta is due to make closest approach at 18:10 CEST 10 July. This image was acquired as part of the optical navigation campaign, in which images acquired by the OSIRIS scientific imager and by Rosetta's on-board navigation cameras are being used to refine estimates of Lutetia's orbital trajectory.

A very nice animation generated from the popular Celestia visualisation tool showing Rosetta flying past Lutetia on 10 July. The animation starts with the 'flip', when Rosetta inverts her orientation before entering fly-by mode (this actually takes 45 minutes, so the animation is accelerated). Then, the animation speeds up again as the distance to Lutetia narrows; you can see the asteroid moving as a tiny dot just behind Rosetta. For the flyby, the animation slows and the point of view jumps to the spacecraft itself; you can see Rosetta automatically slewing to stay pointed at Lutetia. After closest approach, the view rotates and you see Lutetia fading into the distance, as Earth moves into view.

Many thanks to Thomas, Gian Luca and Armelle!

PS: Click here to access larger version

The last optical navigation slot (Slot 19) was just completed a few minutes ago. With this data, ESA Flight Dynamics are now going to compute the final orbit for the flyby, and make a final decision on whether mission controllers should use the last Trajectory Correction Manouevre (TCM) slot, at 12hrs before closest approach on 10 July. -- Daniel

We've just updated yesterday's blog post, ESA's Herschel and Rosetta team up for joint observations, with a pair of excellent animations showing what each of Rosetta and Herschel may see from their respective vantage points during the same timeframe leading up to, at and after closest approach.

The animations show how scientists aim to compare and correlate data gathered from two ESA missions observing at the same time from two very separate vantage points. 

Click here to access the full post and animations (or click on the graphic at left) - and thanks to Laurence, Thomas and the MACH-8 group. -- Daniel

Note: ESA science editor - and Rosetta blog contributor - Stuart Clark sent in a report earlier this morning providing an excellent description of the science activities planned for Lutetia flyby; a number of instruments are already active, including the OSIRIS imaging system (which was used for the past several weeks for optical navigation). We've combined Stuart's excellent write-up with a listing of the instruments, their operation dates and their planned observations/investigation targets. This list was compiled by ESA's Michael Küppers, who works at the Rosetta Science Operations Centre at ESAC, Spain. -- Daniel

Lutetia is a mystery. It returns confusing signals to ground-based telescopes, effectively hiding its composition. At various times, it has displayed characteristics of both 'C-type' carbonaceous asteroids and 'M-type' metallic asteroids. If it is C-type, it is a primitive remnant from the era of planetary formation. If it is M-type, it is a fragment of a once much larger asteroid that has been shattered by a collision.

Rosetta will use its extensive complement of instruments to investigate the mystery, looking for a definitive answer to Lutetia’s composition and for a complete characterisation of this remarkable little world. 

Full text after the jump!

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ESA's Kirstin Wirth also sent in a nice photo today showing the Rosetta science team, all based at the Rosetta Science Operations Centre (RSOC), at ESAC, Spain. She wrote:

The RSOC (at the European Space Astronomy Centre, ESAC, near Madrid) completed delivery of the fly-by science operations plans to the mission operations team at ESOC in June. These files mainly comprise a detailed schedule of flyby experiment observations, the spacecraft pointing plan and the timeline of telecommand sequences to be uplinked to the instruments. Currently, the team at the RSOC are following up the implementation of the science plan and are supporting the colleagues at ESOC in making small, last-minute updates. A part of the team will be co-located at ESOC, in Darmstadt, on 10 July. In addition, we are also looking ahead in time, as we are now collecting requirements from the individual instrument teams to prepare the instruments for entry into deep space hibernation.

L-R: Claire Vallat, Juan Jose Garcia Beteta, Michael Küppers (behind Rosetta), Kristin Wirth (in front of Rosetta), Viney Dhiri