Starship Asterisk*

I read over a paper by I. N. Belskaya et al titled "Puzzling asteroid 21 Lutetia: our knowledge prior to the Rosetta fly-by." Rosetta is ESA's comet rendezvous mission, which will enter orbit around comet 67P/Churyumov-Gerasimenko in May 2014 after a decade-long cruise. On the way to the comet, it's had three flybys of Earth and two planned encounters with asteroids, one with Šteins on September 5, 2008 and the other planned for 21 Lutetia on July 10, 2010 -- that is, in less than three months.

Lutetia is a main belt asteroid with an elliptical orbit that takes it from 2.0 to 2.8 astronomical units from the Sun. As you can tell from its low number (and thus early discovery date, in this case 1852), Lutetia is a relatively big asteroid. Belskaya and coworkers list its size as 132 by 101 by 76 kilometers, making it similar in dimensions to Saturn's moon Epimetheus. That makes it bigger, by far, than any asteroid yet visited; in fact, it's bigger than all the previously visited asteroids combined. If you drew the shape of Lutetia atop the montage I posted before, it could easily cover up the pictures of all the previously visited bodies.

The two equatorial dimensions (the larger two) are fairly well constrained -- there's an uncertainty of only 1 kilometer in those dimensions -- but the polar dimension has large uncertainty of about 31 kilometers. That's because Lutetia's spin pole is nearly horizontal, and most Earth observations have looked more or less directly down onto the pole.

Apart from that, it has been difficult to learn much about Lutetia because its spectrum is nearly featureless. What does that mean? When astronomers use prisms to spread the light from Lutetia and see how bright it is at different wavelengths, they find very little variation in its brightness from wavelength to wavelength. When surfaces are freshly broken, a graph of the brightness versus wavelength will have dips in it where specific minerals absorb light. Lutetia shows no such dips, so it's hard to determine what it may be made of. One conclusion they could draw is that the asteroid is very likely covered with a layer of fine-grained dust (that is, dust particles smaller than 20 microns), which would help to obscure any spectral features.

While there isn't much spectral variation, there is a lot of variation in the polarization of the light reflected by the asteroid as it rotates, and that suggests that Lutetia probably has at least one huge impact crater, and likely more, giving it a distinctly non-round shape.

Although it's hard to conclude much from the spectral information, the spectral data and polarimetric data, taken together, make Lutetia unusual among asteroids, so we're likely to see something distinctly different from asteroids that have been visited before.

21 Lutetia has puzzled astronomers since its discovery. Now they have made a daring set of predictions about what the Rosetta spacecraft will find when it flies past this mysterious asteroid in July.

On 10 July, the European Space Agency's Rosetta spacecraft will fly within a few thousand kilometres of 21 Lutetia, a main belt asteroid that orbits the Sun between Mars and Jupiter.

Lutetia is an unusual object. It is classified as an M-type asteroid, which are thought to be made mainly of nickel and iron. However, Lutetia's spectrum does not seem to show any evidence of metals. In fact, exactly what Lutetia is made of puzzles astronomers. That's partly why it was chosen for the fly by.

So come July, astronomers should know the answer to this conundrum. But in the run up, they're indulging in a little fun. The game they've invented is to see how good a prediction they can make about what Rosetta will find.

Today, Irina Belskaya at the Observatoire de Paris and a few friends take a stab. They make several detailed predictions about Lutetia based partly on observations dating back to the 1960s but mostly on data taken since 2004, when interest picked up after the asteroid was chosen as a flyby target.

So what do they think Rosetta will find?

Belskaya and company say that Lutetia will be 132x101x76 km in size (that's technically known as potato-shaped). They say its texture and mineral content will vary across its surface. At least part of Lutetia's surface will be covered by a layer of loose dust having a mean grain size less than 20 micrometres across. And Lutetia's surface will be made of stuff that has more in common with the carbonaceous chondrite meteorites found on Earth than the iron-nickel ones.

But they're most interesting prediction is that Lutetia will be "non-convex" in shape. That means a large crater will be visible on its surface. In fact its shape will be dominated by this crater.

• arXiv.org > astro-ph > arXiv:1003.1845 > 09 Mar 2010

ESA’s comet-chaser Rosetta is heading for a blind date with asteroid Lutetia. Rosetta does not yet know what Lutetia looks like but beautiful or otherwise the two will meet on 10 July.

Like many first dates, Rosetta will meet Lutetia on a Saturday night, flying to within 3200 km of the space rock. Rosetta started taking navigational sightings of Lutetia at the end of May so that ground controllers can determine any course corrections required to achieve their intended flyby distance.

The close pass will allow around 2 hours of good imaging. The spacecraft will instantly begin beaming the data back to Earth and the first pictures will be released later that evening.

Rosetta flew by asteroid Steins in 2008 and other space missions have encountered a handful of asteroids. Each asteroid has proven to be an individual and Lutetia is expected to continue the trend.

For a start, no one knows what it looks like. Orbiting in the main belt of asteroids between Mars and Jupiter, it appears as a single point of light to ground telescopes. The continuous variation in its brightness makes it clear that Lutetia is rotating and has an uneven surface. These observations allow astronomers to estimate its shape and size, but their determinations all differ.

Initially it was thought that Lutetia is around 95 km in diameter but only mildly elliptical. A more recent estimate suggests 134 km, with a pronounced elongation. Rosetta will tell us for certain and will also investigate the composition of the asteroid, wherein lies another mystery.

By any measure, Lutetia is quite large. Planetary scientists believe that it is a primitive asteroid left on the shelf for billions of years because no planet consumed it as the Solar System formed. Indeed, most measurements appear to back this picture, making the asteroid out to be a ‘C-type’, which contains primitive compounds of carbon.

However, some measurements suggest that Lutetia is an ‘M-type’, which could mean there are metals in its surface. “If Lutetia is a metallic asteroid then we have found a real winner,” says Rita Schulz, ESA Rosetta Project Scientist.

That is because although metallic asteroids do exist, they are thought to be fragments of the metallic core of larger asteroids that have since been shattered into pieces. If Lutetia is made of metal or even contains large amounts of metal, Dr Schulz says that the traditional asteroid classification scheme will need rethinking. “C-class asteroids should not have metals on their surfaces,” she says.

Asteroid science stands to gain once this observational conundrum is resolved because Rosetta’s data will provide a valuable collection of ‘ground truths’ that can be used to resolve conflicting ground-based observations not just for Lutetia but for other asteroids as well.

For 36 hours around the moment of closest approach, Rosetta will be in almost continuous contact with the ground. The only breaks will come as Earth rotates and engineers have to switch from one tracking station to another.

Good contact is essential because the uncertainties in the asteroid’s position and shape may demand last minute fine-tuning to keep it centred in Rosetta’s instruments during the flyby. “The skeleton of the operation is in place, and we have the ability to update our plans at any time,” says Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager.

Stay in touch with the flyby as it happens by visiting the Rosetta blog.

Emily Lakdawalla wrote:

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  Lutetia in sight: Rosetta's first sight of a pinpoint of light from its next target, asteroid Lutetia, was snapped by one of its navigational cameras on May 31, 2010, as it swooped toward a planned 3,160-kilometer flyby at 15:44:53 UTC July 10. (Credit: ESA)

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  All asteroids and comets visited by spacecraft as of September 2008: The total of four comets and eight asteroid systems (including nine separate bodies) that have been examined up close by spacecraft are shown here to scale with each other (75 meters per pixel, in the fully enlarged version). Most of these were visited only briefly, in flyby missions, so we have only one point of view on each; only Eros and Itokawa were orbited and mapped completely. Credits: Montage by Emily Lakdawalla. All images NASA/JPL/Ted Stryk except: Mathilde: NASA/JHUAPL/Ted Stryk; Steins: ESA/OSIRIS team; Eros: NASA/JHUAPL; Itokawa: ISAS/JAXA/Emily Lakdawalla; Halley: Russian Academy of Sciences/Ted Stryk; Tempel 1: NASA/JPL/UMD; Wild 2: NASA/JPL.

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It's unimpressive now, but in a few weeks the pinpoint of light at the center of this photo of a starry sky will loom very large to Rosetta's cameras. The image (top right) is Rosetta's first view of its next target, asteroid 21 Lutetia.

I can't wait to see Lutetia. I've been thinking a lot about Itokawa lately, which was the smallest asteroid yet visited by a spacecraft. Lutetia will be the largest by far, double the size of the largest previously visited one, Mathilde.

Optical navigation images like the one above are used by the mission to fine-tune their understanding of the position of Lutetia in the sky. Analysis of the latest images has shown that, without a rocket burn, Rosetta would pass within 2639 kilometers of Lutetia, more than 500 kilometers closer than desired. So they plan to do a trajectory correction maneuver tomorrow to position Rosetta farther from the asteroid at closest approach. Why would you want to go farther? Via the Rosetta blog, Rosetta spacecraft operations manager Andrea Accomazzo explains:

If we fly closer than 3160 km, then the asteroid image will 'fill up' the cameras' field of view at closest approach. And then not only will we not see the full asteroid but, since the camera image guides the spacecraft attitude, we also would not know at what spot on the asteroid surface we are pointing. Moreover, the science teams have prepared commands for the spacecraft's instruments assuming a certain pre-set distance range from the asteroid.

If we do not pass by within this planned range, we might hamper their observations. It is true that we will use fuel for this correction, but it is very little compared to entire mission and it is far below the amount allocated for this flyby. To be precise, we will only use something in the order of 300 g of fuel.

The blog also quotes Rosetta flight dynamics head Trevor Morley as saying that:

Although the main reason for tweaking the Rosetta trajectory is to increase the fly-by distance, a secondary reason is to ensure that the solar phase angle passes through zero so that at about 18 minutes before closest approach (at a separation distance of 16 400 km) the asteroid, as viewed from the spacececraft, will be seen fully illuminated.

Over the next weeks, Rosetta will approach slowly and that pinpoint of light will get larger and larger. I won't be posting much about the approach though, as I am going to be on vacation for the two weeks from June 20 through July 4. I'll pick things up again in those final days of the approach, and I'm sure Rosetta and Lutetia will be the main things I'll post about when I get back! In the meantime, to get your Rosetta fix, read the wonderful Rosetta blog on the ESA website (which is where I will be getting most of my news anyway).

Jennifer Ouellette wrote:Is it just me, or does the European Space Agency (ESA) employ an aspiring soap opera screenwriter to produce its highly entertaining press releases? Last week, we were treated to the breathless announcement of the Rosetta spacecraft's pending "blind date" with an asteroid named Lutetia on July 10th. One can almost hear the sorority school giggling in sentences like this: "Rosetta does not yet know what Lutetia looks like, but beautiful or otherwise, the two will meet... on a Saturday night."

Anyone who's ever been on a blind date knows this is a scenario just primed for crushing disappointment. First of all, "Lutetia" is a name that screams "High-Maintenance Asteroid with Entitlement Issues." And scientists have no idea what she looks like, although ground-based telescopes have offered a few clues, like the fact that the asteroid is rotating. The poor thing has an "uneven surface" and is (ahem) "quite large" -- as much as 134 kilometers in diameter -- possibly with a "pronounced elongation."

That doesn't sound too promising, but perhaps her beauty is more about substance than superficial style. And that's bad news for Lutetia, because Rosetta is a bit of a player. Sure, it's been called the "comet chaser," since its been betrothed since birth to Comet 67P/Churyumov-Gerasimenko. But the spacecraft isn't due to reach that "mini ice world" until 2014, and it was launched in 2004. It gets lonely in deep space. So who can blame Rosetta for dabbling in a mild flirtation with asteroid Steins in 2008, for example, and any other pretty little rocks it might encounter along the way?

One of the scientific questions the date with Rosetta could answer is whether Lutetia is a "C-type" asteroid -- containing simple compounds of carbon, and hence "a primitive asteroid left on the shelf for billions of years because no planet consumed it as the Solar System formed." Yeah, that's right: Lutetia could be an old maid, the asteroid no solar system really wanted.

Then again, maybe Lutetia is, instead, that rarest of "M-type" asteroids, with lots of metals in her surface. That would make her "a real winner," in the words of ESA's Rosetta Project Scientist Rita Schultz. It would be like discovering the heavyset Plain Jane your folks fixed you up with is heiress to an enormous fortune or something.

The Rosetta orbiter, which carries the DLR lander Philae, has completed more than two thirds of its journey to the comet Churyumov-Gerasimenko. The most comprehensive cometary investigation ever, the mission will deliver DLR's Philae lander to the comet’s surface for in situ studies. The spacecraft and lander are due to close in on 21 Lutetia, a large Main Belt Asteroid on 10 July.
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At 100 kilometres in size, 21 Lutetia is one of the larger Main Belt Asteroids. The lander will investigate whether the asteroid has a magnetic field and an exosphere, and study their characteristics.

Philae will first be switched on between 12:45 and 15:05 CEST on 7 July so the team can prepare the lander for activities around closest approach. The lander will perform science observations on 10 July.

Philae to help uncover Lutetia's true nature

This observation sequence will take place during the asteroid flyby itself, with the lander switching on at 08:45 CEST on 10 July. It will be on throughout the flyby; closest approach is scheduled for 17:45 CEST. The lander and orbiter will be 3169 kilometres from Lutetia, according to recent estimates.

Three instruments on the lander will be switched on during the flyby:

• The Rosetta Lander Magnetometer and Plasma Monitor, ROMAP, is a magnetometer and plasma monitor that will study the local magnetic field and monitor the interactions between the comet and the solar wind.
• MODULUS PTOLEMY is one of two evolved gas analysers, which obtains accurate measurements of isotopic ratios of light elements by heating solid samples to release volatiles.
• The Cometary Sampling and Composition experiment, COSAC, is also an evolved gas analyser. It detects and identifies complex organic molecules from their elemental and molecular composition.

ROMAP will be measuring continuously while it is on (between 7:06 am and 5:50 pm CEST) and will be looking for interactions between the asteroid's magnetic field and the solar wind. COSAC and PTOLEMY will perform a series of ‘sniff’ measurements (five by PTOLEMY and two by COSAC), which will be used to help determine whether or not the asteroid has an exosphere.

On July 10, 2010, at 15:44:56 UTC, the Rosetta spacecraft will fly within 3,162 kilometers of the largest asteroid yet visited by a spacecraft. Named (21) Lutetia, the 132-by-101-by-76-kilometer-diameter body is a puzzle to astronomers, who have been unable to determine its composition. Both the Rosetta orbiter and its still-attached Philae lander have a full slate of science observations planned for the encounter, which will serve both as a test of its instruments and procedures to prepare for its eventual cometary mission and as an opportunity to observe a unique solar system body.
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Unfortunately, I won't be able to watch the whole event live, but, fortunately, you will. That's because ESA is doing a live stream webcast to help people around the world follow one of the biggest space events of 2010. You can watch ESA's streams here, here, or here; I also plan to embed the live stream into a blog entry here on Friday night my time. I'll also provide links to anybody I know of who plans to be live-Tweeting the encounter and who might be a reasonably knowledgable commentator. I am hoping that Andy Rivkin will be one such commentweeter; his thesis was actually observational work on Lutetia! If live streams are not your style or if you'll be enjoying your Saturday outdoors or at a World Cup party, you can keep up with events via ESA's terrific Rosetta blog. I'll be tuned in to the beginning of the events but will be on a plane when the first images are expected to be released.
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Although Lutetia is a large asteroid and therefore not as challenging to track from Earth as its smaller neighbors, optical navgiation by the spacecraft is still critical to ensuring that Rosetta passes by Lutetia at the right distance and with the right position with respect to the Sun. Too far, and Rosetta will fail to achieve the best possible science at the asteroid; too close, and the asteroid will more than fill the view of the spacecraft's cameras, with parts of it cut off at the edges of images. In addition, scientists want the spacecraft to pass precisely between Lutetia and the Sun, permitting the cameras to see Lutetia's surface at "zero phase" -- that is, fully illuminated by the Sun -- a geometry that will aid scientists in understanding the nature of Lutetia's surface.
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The encounter will happen fast, at a relative speed of 15 kilometers per second, so Rosetta's cameras will only resolve Lutetia as more than a speck of light for a few hours around closest approach. Four hours before closest approach, Rosetta will perform its flip while keeping the asteroid in its field of view. The flip will take 40 minutes to complete. At about 12:45 UT, the spacecraft will begin autonomous tracking of the asteroid, examining its own navigational images to ensure that the asteroid remains within its science instruments' field of view.

Five minutes before closest approach, at about 15:40 UT, as Rosetta continues tracking the asteroid, its high-gain antenna will rotate off of Earth line. As the spacecraft is too distant from Earth (more than 3 astronomical units) for the signal from its low-gain antenna to be detectable, this means that communications will cease until after the encounter has ended and Rosetta has turned toward Earth again. It takes 25 minutes for its signals to reach us, so the loss of signal is expected to begin at about 16:05 on Earth. It should last for about 40 minutes, until 16:45 UT. On-time reacquisition of the signal will be ESA's first indication of a successful flyby. ...

A billion-euro (1.25-billion-dollar) European spacecraft will get up close and personal with an asteroid this Saturday as the probe blasts through the Solar System on its way to rendezvous with a comet. The flyby comes halfway in the extraordinary tale of the European Space Agency's Rosetta, launched in 2004 on a 12-year, 7.1-billion-kilometre (4.4-billion-mile) mission.

One of the biggest gambles in the history of space exploration, the unmanned explorer is designed to meet up in 2014 with Comet 67/P Churyumov-Gerasimenko 675 million kms (422 million miles) from home. The goal is to unlock the secrets of these lonely wanderers of the cosmos, whose origins date back to the dawn of the Solar System, some 4.5 billion years ago, before planets existed.
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Once widely dismissed as bland lumps of debris left over from the building of the planets, asteroids have turned out to be intriguingly individual. They are extremely different in shape and size, from just hundreds of metres (yards) across to behemoths of 100 kms (60 miles) or more, and also vary in mineral flavours. Most measurements suggest Lutetia is a "C" type of asteroid, meaning that it contains primitive compounds of carbon. But others indicate it could be an "M" type, meaning that it holds metals ... it could rewrite the theory about asteroid classification. Metallic asteroids are far smaller than Lutetia: they are deemed to be fragments of far larger rocks that, in the bump and grind of the asteroid belt, were smashed apart.

In July next year, Rosetta goes into deep hibernation to save power. If all goes well, it will wake up in January 2014 and then send down a refrigerator-sized lab called Philae, which will anchor onto the comet's icy crust and carry out tests of its surface. For all their scientific rigour, the Rosetta team will be crossing every finger that the Big Sleep will go well, admitted Schwehm. "You don't want in your wildest dreams to be sitting there in 2014 and the little beast doesn't switch on," he said wryly.

On 10 July, ESA's Rosetta will fly past 21 Lutetia, the largest asteroid ever visited by a satellite. After weeks of manoeuvres and a challenging optical navigation campaign, Rosetta is perfectly lined up to skim by at 3162 km at 18:10 CEST.

Rosetta is expected to pass Lutetia at a relative speed of 54 000 km/hr, when both are located some 454 million km from Earth. As Lutetia is a major scientific target of Rosetta's mission, most of the orbiter and lander instruments will be on for flyby, studying the asteroid's surface, dust environment, exosphere, magnetic field, mass and density.
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Time-line of critical events 10 July

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    Time 	Event
00:00:00 	Start of tracking - NASA/DSN Goldstone (GDS)
00:25:05 	Start - Rosetta's NAVCAM asteroid tracking
05:30:00 	End of tracking - NASA /DSN Goldstone (GDS)
05:33:00 	Start of tracking - ESA/ESTRACK New Norcia station (NNO)
08:00:00 	Final telecommands for flyby ready from ESA Flight Dynamics team
10:00:00 	Uplink of updated final fly-by commands
10:20:00 	Start of tracking - NASA/DSN Canberra (CAN)
12:20:00 	End of tracking - NASA/DSN Canberra (CAN)
13:05:00 	Start of tracking - ESA/ESTRACK Cebreros (CEB) & NASA/DSN Madrid (MAD)
14:30:00 	End of tracking - ESA/ESTRACK Cebreros station (CEB)
15:26:00 	End of tracking - ESA/ESTRACK New Norcia station (NNO)
13:50:07 	Start Rosetta flip manoeuvre
14:30:07 	End Rosetta flip manoeuvre
15:10:07 	Start asteroid closed-loop tracking - Rosetta on self-navigation
18:00:00 	Start media event live from ESA/ESOC
18:05:07 	Stop - radio communications via high-gain antenna - Loss of signal (earliest)
18:10:07 	Closest approach to Lutetia
18:20:07 	End asteroid closed-loop tracking
18:45:07 	Resume radio communications via high-gain antenna - Acquisition of signal (latest)
18:47:00 	Media event pause
20:05:35 	Start science data downlink
23:00:00 	Resume media event - Science team presents data
23:45:00 	End media event
23:55:00 	End of tracking - NASA/DSN Madrid (MAD)

Note:

• Times shown are ground event times in Central European Summer Time (CEST = UTC/GMT + 2 hours).
  Spacecraft event time is 25 mins and 21 secs earlier. All times are estimates and may change.
  
  Watch the live fly-by webcast from ESA/ESOC, 10 July 2010, starting 18:00 CEST.

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Rosetta approaches Lutetia (OSIRIS image) 2010 July 09 01:00 UTC
about two million kilometers (and 36 hours) from the asteroid
(Credit: ESA/MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA)

Rosetta's most important job over the last few months has been to observe how the position of asteroid (21) Lutetia shifts against the background of fixed (fixed, that is, as far as Rosetta can see) stars. In a technique whose heritage can be traced to the skywatching of Earth's most ancient mariners, Rosetta (and, of course, its human navigators) employs the background stars to help it determine its course.

That optical navigation campaign is now complete; Rosetta has done its best to chart the course of Lutetia, and ESA's navigators will examine its photos to determine whether Rosetta's course is okay as currently set, or whether one final tiny puff of its thrusters is needed to steer the spacecraft past the asteroid at the desired distance. They've already said, though, when they made their decision to cancel the possible encounter-minus-40-hour thruster firing, that they expected the encounter-minus-12-hour firing would not be needed.

If you want to follow all these events in real time, Daniel Muller has, as usual, a great online countdown clock listing all the events.

Here is one of the last photos taken as part of the optical navigation campaign, by Rosetta's sharpest camera, OSIRIS. You can't really say much about the asteroid from this photo -- its exposure is set to pick up faint background stars, so the view of the asteroid itself is overexposed -- but clearly Lutetia is in Rosetta's sights.

Closest approach happens at 15:44:56 UTC July 10, or about 21 hours from now. Let's all hope all the instruments and electronics operate perfectly for the upcoming encounter with the biggest asteroid yet seen up close!

ESA Rosetta Blog
ESA Rosetta Portal
ESA Rosetta Webcast (live)
NASA JPL-Caltech Rosetta Website

On its way to a 2014 rendezvous with comet 67P/Churyumov-Gerasimenko, the European Space Agency's Rosetta spacecraft, with NASA instruments aboard, will fly past asteroid Lutetia this Saturday, July 10.

The instruments aboard Rosetta will record the first close-up image of a metal asteroid. They will also make measurements to help scientists derive the mass of the object, understand the properties of the asteroid's surface crust, record the solar wind in the vicinity and look for evidence of an atmosphere. The spacecraft will pass the asteroid at a minimum distance of 3,160 kilometers (1,950 miles) and at a velocity of 15 kilometers (9 miles) per second.

"Little is known about asteroid Lutetia other than it is about 100 kilometers (62 miles) wide," said Claudia Alexander, project scientist for the U.S. role in the Rosetta mission, from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Allowing Rosetta's suite of science instruments to focus on this target of opportunity should greatly expand our knowledge of this huge space rock, while at the same time giving the mission's science instruments a real out-of-this-world workout."

Previous images of Lutetia were taken by ground-based telescopes and show only hints of the asteroid's shape. Lutetia will be the second asteroid to receive the full attention of Rosetta and its instruments. The spacecraft previously flew within 800 kilometers (500 miles) of asteroid Steins in September of 2008. The Lutetia flyby is the final scientific milestone for Rosetta before controllers put the spacecraft into hibernation early in 2011, only to wake up in early 2014 for approach to comet 67P/Churyumov-Gerasimenko.

NASA has contributed an ultraviolet instrument (Alice); a plasma instrument (the Ion and Electron Sensor); a microwave instrument (Microwave Instrument for the Rosetta Orbiter); and portions of the electronics package for the double focusing mass spectrometer of the Rosetta orbiter sensor for ion and neutral analysis (ROSINA), among other contributions to this international mission. NASA's Deep Space Network, managed by JPL, will be providing support for tracking and science operations.

JPL manages NASA's participation in the Rosetta mission. Learn more about NASA's contribution to Rosetta at: http://rosetta.jpl.nasa.gov.

bystander wrote:Heavy Metal Rock Set to Take the Stage
NASA JPL Rosetta (210-228) | 09 July 2010

NASA has contributed an ultraviolet instrument (Alice); a plasma instrument (the Ion and Electron Sensor); a microwave instrument (Microwave Instrument for the Rosetta Orbiter); and portions of the electronics package for the double focusing mass spectrometer of the Rosetta orbiter sensor for ion and neutral analysis (ROSINA), among other contributions to this international mission. NASA's Deep Space Network, managed by JPL, will be providing support for tracking and science operations.

JPL manages NASA's participation in the Rosetta mission. Learn more about NASA's contribution to Rosetta at: http://rosetta.jpl.nasa.gov.

http://en.wikipedia.org/wiki/Hermann_Goldschmidt wrote:
<<Hermann Mayer Salomon Goldschmidt (June 17, 1802 – April 26, 1866) was born in Frankfurt as the son of a Jewish merchant. During a journey to Holland, Goldschmidt visited Dutch picture galleries. The impression of this visit convinced him to become a painter. He studied art in Munich for several years under supervision of such famous painters as Peter von Cornelius and Julius Schnorr von Carolsfeld. To complete his education, in 1836 Goldschmidt went to Paris. Several lectures on astronomy were planned for the occasion of the lunar eclipse of March 31, 1847. Urbain Le Verrier, discoverer of Neptune, held one in the Sorbonne. By pure chance, Goldshmidt attended this lecture, which awakened his interest in astronomy and led him to pursue it as a career.

Goldschmidt bought a telescope with the diameter of 23 lines (2.0 in) with the money he got from selling two portraits of Galileo he painted during a stay in Florence. Goldschmidt set up the telescope in his apartment on the sixth floor above the Café Procope. Very soon he started updating the Star charts he had with new stars. During this work he observed the same area several times and was able to detect variable stars and moving objects like planets. He discovered his first new "planet" (21 Lutetia) on November 15, 1852. Goldschmidt confirmed his observations with the help of François Arago at the Paris Observatory on November 18. Aragon suggested the name Lutetium, based on the Latin name of Paris Lutetia used during the Roman occupation. The discovery of the new planet was published on November 23.

In subsequent years, Goldschmidt bought larger telescopes, one with 30 lines diameter. Despite the limited observational capabilities of his instrument, which was inferior to those of most of his competitors, by May 1856 Goldschmidt had discovered four more asteroids. His next telescope was one with the diameter of 4 inches. This technical improvement enabled him to discover nine asteroids between May 1857 and May 1861. During that period, the Academy of Science awarded Goldschmidt the astronomical prize medal several times, and he was made a chevalier of the Légion d'honneur in 1857. By the time of his final discovery in May 1861, the Royal Astronomical Society had awarded him the Gold Medal of the Royal Astronomical Society for the discovery of 13 asteroids. At that point, the second most successful astronomer John Russell Hind had discovered 10.

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Goldschmidt asteroids:

14 21 Lutetia 	November 15, 1852
32 Pomona 	October 26, 1854
36 Atalante 	October 5, 1855
40 Harmonia 	March 31, 1856
41 Daphne 	May 22, 1856
44 Nysa 	May 27, 1857
45 Eugenia 	June 27, 1857
48 Doris 	September 19, 1857
49 Pales 	September 19, 1857
52 Europa 	February 4, 1858
54 Alexandra 	September 10, 1858
56 Melete 	September 9, 1857
61 Danaë 	September 9, 1860
70 Panopaea 	May 5, 1861

Goldschmidt combined his abilities as a painter with his love for astronomy as exemplified by his paintings of the Great Comet of 1858 and of the solar eclipse he observed in Spain July 1860. Goldschmidt was never employed at the Paris Observatory and therefore his income was insecure. However, in 1862 he was awarded a pension of 1500 francs. Because of his diabetes, Goldschmidt moved to Fontainebleau, but his condition did not improve. He stayed in Fontainebleau for three years and died there on April 26, 1866.

The lunar crater Goldschmidt is named after him. The crater is located in the northern polar region. To Honor Goldschmidt, the asteroid 1614 Goldschmidt was named after him. The Rosetta spacecraft is scheduled to visit the asteroid Lutetia on July 10, 2010. During the fly by, the instruments of the spacecraft, which is on its way to investigate a comet in 2014, will be used to collect scientific data about the Lutetia.>>

http://en.wikipedia.org/wiki/Caf%C3%A9_Procope wrote:
<<Café Procope, in rue de l'Ancienne Comédie, 6th arrondissement, is one of the oldest restaurants of Paris. It was opened in 1686 by the Sicilian Francesco Procopio dei Coltelli, with a slyly subversive name adopted from the historian Procopius, whose Secret History, the Anekdota, long known of, had been discovered in the Vatican Library and published for the first time ever in 1623: it told the scandals of Emperor Justinian, his ex-dancer Empress, and his court.

Café Procope, in the street then known as rue des Fossés-Saint-Germain-des-Prés, started as a café where gentlemen of fashion might drink coffee, the exotic beverage that had previously been served in taverns, or eat a sorbet, served up in porcelain cups by waiters in exotic "Turkish" garb. The escorted ladies who appeared at Café Procope in its earliest days soon disappeared. In 1689 the Comédie française was established across the street— hence the street's modern name— and the Procope became known as the "theatrical" café, and remained so: it was to the Procope on 18 December 1752 that Rousseau retired before the performance of his last play Narcisse had even finished, all too aware, now that he had seen it mounted, he said publicly, how boring it all was on the stage.

At Café Procope: at rear, from left to right: Condorcet, La Harpe, Voltaire (with his arm raised) and Diderot.

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It was the unexampled mix of habitués that surprised visitors, though no one remarked on the absence of women. Louis, chevalier de Mailly, in Les Entretiens des caffés, 1702, remarked:

• “The cafés are most agreeable places, and ones where one finds all sorts of people of different characters. There one sees fine young gentlemen, agreeably enjoying themselves; there one sees the savants who come to leave aside the laborious spirit of the study; there one sees others whose gravity and plumpness stand in for merit. Those, in a raised voice, often impose silence on the deftest wit, and rouse themselves to praise everything that is to be blamed, and blame everything that is worthy of praise. How entertaining for those of spirit to see originals setting themselves up as arbiters of good taste and deciding with an imperious tone what is over their depth!”

Throughout the eighteenth century, the brasserie Procope was the meeting place of the intellectual establishment, and of the nouvellistes of the scandal-gossip trade, whose remarks at Procope were repeated in the police reports. Not all the Encyclopédistes drank forty cups of coffee a day like Voltaire, who mixed his with chocolate, but they all met at Procope, as did Benjamin Franklin, John Paul Jones and Thomas Jefferson.

Alain-René Lesage described the hubbub at Procope in La Valise Trouvée (1772): "There is an ebb and flow of all conditions of men, nobles and cooks, wits and sots, pell mell, all chattering in full chorus to their heart's content."In the increasingly democratic mix it will be noted there were still no women. Writing a few years after the death of Voltaire, Louis-Sébastien Mercier noted:

• “All the works of this Paris-born writer seem to have been made for the capital. It was foremost in his mind when he wrote. While composing, he was looking towards the French Academy, the public of Comédie française, the Café Procope, and a circle of young musketeers. He hardly ever had anything else in sight.”

During the Revolution, the Phrygian cap, soon to be the symbol of Liberty, was first displayed at the Procope; the Cordeliers, Robespierre, Danton and Marat all used the cafe as a meeting place. After the Restoration, another famous customer was Alexander von Humboldt, who lunched here during the 1820s every day from 11am to noon. The Procope retained its literary cachet: Alfred de Musset, George Sand, Gustave Planche, the philosopher Pierre Leroux, M. Coquille, editor of Le Monde, Anatole France were all regulars. Under the Second Empire, August Jean-Marie Vermorel of Le Reforme or Léon Gambetta would expound their plans for social reform.

Café Procope was refurbished in 1988 to 1989 in eighteenth-century style. It received Pompeian red walls, crystal chandeliers, eighteenth century oval portraits of famous people that have been patrons, and a tinkly piano. The waiters were dressed in quasi-revolutionary uniforms. This oldest cafe in Paris in continuous operation since it opened in 1686 is on rue de l'Ancienne Comedie.>>

http://webservices.esa.int/blog/post/5/1241 wrote:
Waiting for a close-up look at Lutetia
10 July, 2010 15:22 -- Stuart

<<I've been in contact with astronomer Andy Rivkin, from the Johns Hopkins University Applied Physics Laboratory, in Maryland, USA.

[Andy] 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. He agreed to answer some questions via mail - access:
-------------------------------------------
Q. What drew your attention to Lutetia in 1996?

• Andy: I was observing asteroids in a part of the infrared spectrum that is sensitive to water, whether as ice or chemically bound into 'hydrated minerals'. These hydrated minerals are seen in some primitive meteorites, where they formed very early in solar system history as radioactive heat melted ice and the resulting water reacted with dry rock. We see evidence for hydrated minerals, particularly larger and darker ones mostly found in the middle and outer asteroid belt. Hydrated minerals can also form on Earth via similar reactions between water and dry rock. Even though water is chemically part of these minerals, you wouldn't think they were 'wet' if you looked at or handled them.
  
  I looked at a number of M-class asteroids, and found that a surprisingly large number of them, roughly a third, showed evidence of hydrated minerals. This was surprising because M asteroids have been associated with iron meteorites, and are not at all expected to have any hydrated minerals.
  
  Lutetia is one of the larger M-asteroids, and one of the ones we found to display evidence of hydrated minerals. Lutetia is also unusual because M asteroids tend to be reddish in colour, while Lutetia is much greyer. Also, it reflects very little radar compared to typical M-asteroids. Finally, two different techniques for determining Lutetia's brightness have found quite different results and it's not clear why. Adding all these unusual factors together make Lutetia look like a member of a different asteroid group, the C-class asteroids. Instead of iron meteorites, these are associated with very primitive meteorites, which contain organic material.

Q. What are you hoping for from the flyby?

• Andy: Taking it all into account, we really don't know what to expect from Lutetia, which is exciting. It is pretty clearly not like any asteroid we have yet visited. I selfishly hope that Rosetta will confirm hydrated minerals on Lutetia, more than 15 years after my thesis observations. But more generally, I'm looking forward to Rosetta's close-up look and to people getting the chance to make sense of all of the unusual measurements.>>

jumpjack wrote:
We'll have to wait till 23:00 CEST for first images release!

jumpjack wrote:First images!
http://webservices.esa.int/blog/post/5/1246

Hi-Res will be available at 23:00 CEST. (21 GMT)

http://www.planetary.org/blog/article/00002578/ wrote:

Click to view full size image

Lutetia -- and Saturn!!

A quick post of just one of the gorgeous images from Rosetta's flyby of Lutetia today; for more, see the Rosetta Blog. But this one was just too pretty to wait for.

The solar system is a very, very empty place. It is incredibly rare to catch two objects passing close to each other. Yet, just as Rosetta was approaching for its flyby of Lutetia, it happened to catch a second solar system object in the background -- and a very recognizable one at that: Saturn!

Credit: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

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The Rosetta spacecraft took its first close-up images of the asteroid Lutetia today, revealing it to be a heavily cratered, elongated rock.

Rosetta got within 2,000 miles of the asteroid, which is about 80 miles long and 4.5 billion years old. The closest images got down to less than 200 feet in resolution.

The spacecraft was traveling at around 9 miles per second, and the whole flyby took less than a minute. The European Space Agency mission is now focused on its primary target, comet Churyumov-Gerasimenko. Rosetta should arrive at the comet in 2014 and hang out with it for a few months and send a lander to the comet nucleus.

Lutetia was chosen as a target for a flyby partly because it is mysterious. It’s unclear whether it is a C-type asteroid leftover from the early formation of the solar system, or an M-type asteroid associated with meteorites and thought to be pieces of the cores of larger objects.

Image: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

• [Chunk and Sloth are chained up together]
  
  Chunk: Hey, mister? Are you hungry? I got a Baby Ruth.
  
  Sloth: Ruth! Ruth! Baby! Ruth!
  
  Chunk: Here you go.
  
  [Chunk tosses the candy bar to Sloth and it hits him in the head. Both scream]
  
  Chunk: I'm sorry, mister! I'm sorry!
  
  [Sloth rips his chains out of the wall and goes to pick up the candy bar. Then, he realizes he's free]
  
  Chunk: Gee, mister. You're even hungrier than I am.

http://www.planetary.org/blog/article/00002579/ wrote:

Rosetta Flugbahn (flight path)

Click to view full size image

The Planetary Society Blog By Emily Lakdawalla
Jul. 10, 2010 | 22:17 PDT | Jul. 11 05:17 UTC
Rosetta's Lutetia pictures

Rosetta's circuitous path through the solar system. Gridlines are astronomical units (average Earth distance from the Sun). The green circle is Earth's orbit ("Erde," in German); blue, Mars; red, comet Churymov-Gerasimenko, Rosetta's eventual target, whose elliptical orbit it must match in order to be able to rendezvous with and land on it in 2014. The dotted gray line is Rosetta's path. Only small portions of the orbits of the two asteroids that Rosetta flew past (Steins and Lutetia) are shown in orange and yellow. Credit: ESA / DLR

[size=150][color=#FF00FF]Lutetia at closest approach[/color][/size]

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[size=150][color=#FF00FF]Lutetia landslide?[/color][/size]

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• • Lutetia in the Light
  For all these years you were merely
  A smear of light through our telescopes
  On the clearest, coldest night; a hint
  Of a glint, just a few pixels wide
  On even your most perfectly-framed portraits.
  But now, now we see you!
  Swimming out of the dark – a great
  Stone shark, your star-tanned skin pitted
  And pocked, scarred after aeons of drifting
  Silently through the endless ocean of space.
  Here on Earth our faces lit up as we saw
  You clearly for the first time; eyes wide
  With wonder we traced the strangely familiar
  Grooves raked across your sides,
  Wondering if Rosetta had doubled back to Mars
  And raced past Phobos by mistake –
  
  Then you were gone, falling back into the black,
  Not to be seen by human eyes again for a thousand
  Blue Moons or more. But we know you now,
  We know you; you’ll never be just a speck of light again.
  
  —Stuart Atkinson

• Image credit: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

bystander wrote:Advice to Rosetta: Maybe She's Just Not That Into You
Discovery News | 21 June 2010

Jennifer Ouellette wrote:
Is it just me, or does the European Space Agency (ESA) employ an aspiring soap opera screenwriter to produce its highly entertaining press releases? Last week, we were treated to the breathless announcement of the Rosetta spacecraft's pending "blind date" with an asteroid named Lutetia on July 10th. One can almost hear the sorority school giggling in sentences like this: "Rosetta does not yet know what Lutetia looks like, but beautiful or otherwise, the two will meet... on a Saturday night."

Anyone who's ever been on a blind date knows this is a scenario just primed for crushing disappointment. First of all, "Lutetia" is a name that screams "High-Maintenance Asteroid with Entitlement Issues." And scientists have no idea what she looks like, although ground-based telescopes have offered a few clues, like the fact that the asteroid is rotating. The poor thing has an "uneven surface" and is (ahem) "quite large" -- as much as 134 kilometers in diameter -- possibly with a "pronounced elongation."

That doesn't sound too promising, but perhaps her beauty is more about substance than superficial style. And that's bad news for Lutetia, because Rosetta is a bit of a player. Sure, it's been called the "comet chaser," since its been betrothed since birth to Comet 67P/Churyumov-Gerasimenko. But the spacecraft isn't due to reach that "mini ice world" until 2014, and it was launched in 2004. It gets lonely in deep space. So who can blame Rosetta for dabbling in a mild flirtation with asteroid Steins in 2008, for example, and any other pretty little rocks it might encounter along the way?

One of the scientific questions the date with Rosetta could answer is whether Lutetia is a "C-type" asteroid -- containing simple compounds of carbon, and hence "a primitive asteroid left on the shelf for billions of years because no planet consumed it as the Solar System formed." Yeah, that's right: Lutetia could be an old maid, the asteroid no solar system really wanted.

Then again, maybe Lutetia is, instead, that rarest of "M-type" asteroids, with lots of metals in her surface. That would make her "a real winner," in the words of ESA's Rosetta Project Scientist Rita Schultz. It would be like discovering the heavyset Plain Jane your folks fixed you up with is heiress to an enormous fortune or something.