[Waspie_Dwarf]

Rosetta Steins fly-by confirmed

5 September 2008

ESA’s Rosetta spacecraft flew by asteroid (2867) Steins on 5 September 2008 at 20:58 CEST, ground received time (= spacecraft time CEST + 20 minutes), with a closest approach distance of 800 km.

Steins is Rosetta’s first nominal scientific target. The spacecraft encountered the asteroid in the course of its first incursion into the main asteroid belt located between the orbits of Mars and Jupiter, while on its way to Comet 67P/Churyumov-Gerasimenko.

The study of asteroids is extremely important because they represent samples of Solar System material at different stages of evolution – key to understanding the origin of our own planet and of our planetary neighbourhood.

Credits: ESA, image by C.Carreau

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.

To optimise the science return from this historic encounter, a series of critical operations were executed before closest approach, some of which required the spacecraft flip over and change its orientation rapidly, pushing it to its design limits.

After the flip, at 20:39 CEST (ground time), Rosetta switched to the asteroid fly-by mode, during which its orientation was automatically controlled by the on-board navigation cameras. The asteroid was tracked continuously and kept it in the field of view of the imaging instruments.

At 20:48 CEST (ground time), while still in asteroid fly-by mode, Rosetta’s high gain antenna was turned away from Earth and the science observations were carried out. Radio contact established again at 22:14 CEST and the first bit of telemetry was received through NASA’s Goldstone antenna.

Science data download will start tomorrow morning, 6 September at about 02:00 CEST and continue through the night. Images and the preliminary results from the fly-by will be presented tomorrow at a press conference which be held at ESOC starting at 12:00 CEST. The press conference will be streamed on the web at www.esa.int/rosetta.

Rosetta flight control team: watching acquisition of signal from the spacecraft, 22:14 CEST 5 September

Credits: ESA

... and celebration!

Credits: ESA

Source: ESA - Rosetta

[Waspie_Dwarf]

Encounter of a different kind: Rosetta observes asteroid at close quarters

6 September 2008

Artist view of ESA's Rosetta cometary probe. The spacecraft is covered with dark thermal insulation in order to keep its warmth while venturing into the coldness of the outer Solar System, beyond Mars orbit.

Selected in November 1993 as a cornerstone mission of ESA's long-term science programme, the Rosetta probe was launched by an Ariane 5 on 2 March 2004, on an 11-year journey to the comet 67P/Churyumov-Gerasimenko.

Built by EADS Astrium, the Rosetta probe consists of a 3,065-kg spacecraft (1,578-kg dry mass) designed to enter orbit around the comet's nucleus in August 2014 after a series of gravity assist manoeuvres to gain enough orbital energy, with three swing-bys at Earth (March 2005, November 2007 and November 2009) and one at Mars (February 2007). En route to the comet, the probe will flyby the asteroids 2867 Steins (September 2008) and 21 Lutetia (July 2010).

The spacecraft carries 11 science instruments to probe the comet's nucleus and map its surface in fine detail. It will also land a package of instruments (the Philae Lander) to study some of the most primitive, unprocessed material in the Solar System. The mission will provide clues to the physical and chemical processes at work during the formation of planets, beginning 4.6 billion years ago.

Credits: ESA, image by AOES Medialab

ESA PR 37-2008 ESA's comet chaser, Rosetta, last night flew by a small body in the main asteroid belt, asteroid Steins, collecting a wealth of information about this rare type of minor Solar System body.

At 20:58 CEST (18:58 UT) last night, ESA's Rosetta probe approached asteroid 2867 Steins, coming to within a distance of only 800 km from it. Steins is Rosetta's first nominal scientific target in its 11½ year mission to ultimately explore the nucleus of Comet 67P/Churyumov-Gerasimenko.

The success of this 'close' encounter was confirmed at 22:14 CEST, when ESA's ground control team at the European Space Operations Centre (ESOC) in Darmstadt, Germany, received initial telemetry from the spacecraft. During the flyby operations, Rosetta was out of reach as regards communication links because its antenna had to be turned away from Earth. At a distance of about 2.41 AU (360 million kilometres) from our planet, the radio signal from the probe took 20 minutes to reach the ground.

Steins is a small asteroid of irregular shape with a diameter of only 4.6 km. It belongs to the rare class of E-type asteroids, which had not been directly observed by an interplanetary spacecraft before. Such asteroids are quite small in size and orbit and are mostly found in the inner part of the main asteroid belt located between Mars and Jupiter. They probably originate from the mantle of larger asteroids destroyed in the early history of the Solar System, and are thought to be composed mainly of silicate minerals with little or no iron content.

The data collected by Rosetta last night and which will be analysed over the coming days and weeks will finally unveil the true nature of Steins.

Through the study of minor bodies such as asteroids, Rosetta is opening up a new window onto the early history of our Solar System. It will give us a better understanding of the origins and evolution of the planets, and also a key to better interpreting asteroid data collected from the ground.


Under Rosetta's scope

This is not Rosetta's first look at Steins. Over two years ago, in March 2006, the Osiris camera onboard Rosetta observed the brightness variations of this rotating asteroid from a distance of 159 million kilometres (a little over the distance between Earth and the Sun), and was able to determine that the tiny asteroid spins around its axis in about six hours.

Together with the two navigation cameras onboard, Osiris was again pointed towards Steins on 4 August and continued to observe the asteroid until 4 September, in order to assist Rosetta's navigation by optical means – a first in the history of ESA spacecraft operations. A few days before the flyby, most of the Rosetta orbiter instruments, as well as the Philae lander magnetometer, were switched on to collect science data on the asteroid, with ever-increasing accuracy as the spacecraft closed in on it.

Rosetta's powerful instruments have initially been focusing on the asteroid's orbital motion, rotation, shape and density. As the distance has diminished, the investigation has broadened to take in the observation of surface properties and features, and the analysis of the chemical and mineralogical composition of the terrains, as well as their relative ages and the effects of the solar wind on the surface.

At its closest approach, Rosetta flew by Steins at a relative speed of 8.6 km/s. To keep the small asteroid in the field of view of its instruments, the spacecraft had to perform a rapid and highly demanding rotation manoeuvre, which had been successfully rehearsed in March this year.

A preliminary analysis of the first data from the flyby was presented to the press at ESOC at 12:00 CEST today.


To Steins and beyond

"Steins might be small, but we're making big science here", said Dr David Southwood, ESA's Director of Science and Robotic Exploration. "The better we learn to know the different kinds of asteroids, the better we will understand our origins in the past. Moreover, when such Solar System wanderers escape from the belt they could become a threat to Earth. The better we know them, the better we will be able to mitigate the risks some of them might present in the future."

"Rosetta performed very well all along," Southwood continued. " This was a complex manoeuvre to keep such a small target in sight, but the spacecraft came through with flying colours. Now we are even more confident in its capacity to conduct the complex tasks that await it at comet Churyumov-Gerasimenko."

Science observations of Steins will continue until 10 September.


Since its launch by an Ariane 5 rocket on 2 March 2004, Rosetta has already travelled about 3.7 thousand million kilometres and swung by the Earth twice and Mars once for gravity-assist manoeuvres. On 17 December this year Rosetta will reach the maximum distance from the Sun in its current orbit, and will then head back towards Earth for the next and last gravitational kick from our planet on 13 November 2009. This will give the probe its final push toward its cometary target.

On its way, Rosetta is scheduled to conduct another flyby, this time with the much larger (21) Lutetia asteroid, on 10 July 2010. Arrival at 67P/Churyumov-Gerasimenko is due by mid-2014. By that time the probe will have covered a distance of about 6.5 thousand million kilometres.


For more information:

ESA - Media Relations Office
Communication and Knowledge Department
Tel: +33 1 5369 7299
Fax: +33 1 5369 7690
Email: media@esa.int


Further information:

ESA - Media Relations Office
Tel: +33 1 5369 7299
Fax: +33 1 5369 7690

Source: ESA - Rosetta

[Waspie_Dwarf]

Steins: A diamond in the sky

6 September 2008

Click HERE for an animation of the closest approach of Rosetta to asteroid Steins (AVI, Size: 3014 kb)

The first images from Rosetta’s OSIRIS imaging system and VIRTIS infrared spectrometer were derived from raw data this morning and have delivered spectacular results.

"Steins looks like a diamond in the sky," said Uwe Keller, Principal Investigator for the OSIRIS imaging system from the Max Planck Institut Fuer Sonnensystemforschung, Lindau.

Visible in the image are several small craters on the asteroid, and two huge ones, one of which is 2 km in diameter, indicating that the asteroid must be very old.

The images are 50 to 60 pixels in diameter, enough to characterise the shape and other characteristics of the body of the asteroid.

Anaglyph image of Steins, taken around the time of Rosetta's closest approach to Steins on 5 September 2008.

Credits: ESA ©2008 MPS for OSIRIS Team MPS/UPM/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Rita Schulz, Rosetta Project Scientist, said, "In the images is a chain of impact craters, which must have formed from recurring impact as the asteroid rotated. The impact may have been caused by a meteoroid stream, or fragments from a shattered small body."

The chain is composed of about 7 craters. To determine the age of the asteroid, a count of the craters on the asteroid’s surface has been started (the more the number of craters, the older the asteroid). So far, 23 craters have been spotted.

From the images, scientists will try and understand why the asteroid is unusually bright, and how fine grains of the surface regolith are. This will tell them more about how the asteroid formed.

Anaglyph image of Steins, taken around the time of Rosetta's closest approach to Steins on 5 September 2008.

Credits: ESA ©2008 MPS for OSIRIS Team MPS/UPM/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Gerhard Schwehm, Mission Manager for Rosetta said, "It looks like a typical asteroid, but it is really fascinating how much we can learn from just the images. This is our first science highlight; we certainly have a lot of promising science ahead of us. I’m already looking forward to encountering our next diamond in the sky, the much bigger Lutetia."


The OSIRIS imaging system's Wide Angle Camera (WAC) worked perfectly through the fly-by.

The OSIRIS team expects that the images that they will retrieve from the Narrow Angle Camera (NAC) will be of comparable resolution. This will add to the detailed colour information and hence to knowledge of the surface composition.

Asteroid Steins seen from a distance of 800 km, taken by the OSIRIS imaging system from two different perspectives. The effective diameter of the asteroid is 5 km, approximately as predicted. At the top of the asteroid (as shown in this image), a large crater, approximately 1.5-km in size, can be seen. Scientists were amazed that the asteroid survived the impact that was responsible for the crater.

Credits: ESA ©2008 MPS for OSIRIS Team MPS/UPM/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Science team members noted that the Narrow Angle Camera (NAC) appears to have switched to safe mode a few minutes before closest approach, but switched back on after a few hours. The software is programmed to switch to safe mode when certain parameter thresholds are crossed to protect the camera. The team will concentrate investigating the reasons for this anomaly once the science data has been analysed.

After analysis of the Rosetta data, Steins will be one of the best-characterised asteroids so far.

Source: ESA - Rosetta

[Waspie_Dwarf]

Last visit home for ESA’s comet chaser

Artist view of ESA's Rosetta cometary probe.

Credits: ESA, image by AOES Medialab

20 October 2009
SA's Rosetta comet chaser will swing by Earth on 13 November to pick up orbital energy and begin the final leg of its 10-year journey to the outer Solar System. Several observations of the Earth–Moon system are planned before the spacecraft heads out to study comet 67/P Churyumov-Gerasimenko.

This will be the third Earth swingby, the last of Rosetta’s four planetary gravity assists. Closest approach to Earth is expected at 08:45 CET. The swingby will provide exactly the boost Rosetta needs to continue into the outer Solar System. The craft is scheduled for a close encounter with asteroid 21 Lutetia in July next year.

Rosetta is expected to arrive at its final destination in May 2014. There, it will release the Philae lander for in-situ studies on the surface. The spacecraft will then escort the comet on its journey toward the Sun, studying it closely for up to two years.

As it closes in on Earth next month, Rosetta will have travelled almost 4500 million km since launch. It will speed past Earth at 13.3 km/s, passing above the Indian Ocean at 109°E, 8°S, just south of the Indonesian island of Java. The gravity-assist will increase the spacecraft's speed by 3.6 km/s with respect to the Sun.


Instruments in action


Artist view of ESA's Rosetta cometary probe.

Credits: ESA, image by AOES Medialab

While the swingby is critical for achieving the velocity required to reach its ultimate destination, the close encounter will also be used to study the Earth–Moon system from Rosetta’s unique perspective.

Several instruments that usually hibernate during the long trek will be turned on in the week before the swingby.


Follow the swingby live

The Rosetta Blog will be updated regularly for this final planetary swingby. Follow crucial events live via the blog and the dedicated ESA Rosetta mission website.


Critical swingby events

Closest approach is scheduled for 08:45 CET on 13 November, but mission operators will perform a number of critical actions before and after the swingby to ensure that Rosetta is on the right trajectory.

One of the most important will be a trajectory correction manoeuvre (TCM), scheduled for 22 October at 14:30 CET. Results of this manoeuvre will be analysed to determine whether additional TCMs are required to achieve the correct approach trajectory.


Notes: All times are in Central European Time (CET/CEST)

• TCM: Trajectory correction manoeuvre
  
• DSN: Deep Space Network (NASA)
  
• DSA: Deep Space Antenna (ESA)

All times are subject to change.

Source: ESA - Rosetta

This post has been edited by Waspie_Dwarf: 05 November 2009 - 04:13 PM

[Waspie_Dwarf]

Rosetta lined up nicely for Earth approach

Artist view of ESA's Rosetta cometary probe.

Credits: ESA, image by AOES Medialab

28 October 2009
Following the first and primary trajectory correction manoeuvre 22 October, Rosetta is lined up nicely for the approach to Earth. The manoeuvre provided an 8.8 cm/s change in orbital velocity and the thruster performance was accurate. Closest approach to Earth is now scheduled for 08:45 CET on 13 November.

The results of last Thursday's trajectory correction manoeuvre (TCM) have been analysed by ESA's Flight Dynamics team at ESOC.

"The manoeuvre was very close to the predicted and required amount. We will continue to analyse the results to determine whether we will need any additional manoeuvres," said Trevor Morley, lead ESA Flight Dynamics specialist working on Rosetta.

To analyse the performance, the team used data from a number of sources, including:

• Telemetry radioed down by Rosetta, including star tracker data and parameters related to fuel usage and thruster operation
  
• Doppler and ranging data received from the ESA and NASA ground stations that have been following Rosetta over the past few days

Based on preliminary analysis, the 86-second thruster burn over-performed slightly, in the range of 0.06-0.07%.


As a result, the predicted time of closest approach, or perigee passage, on 13 November is 08:45:40 CET. This estimate will be updated in the next few days.


The team have slots of additional TCMs at 1 week, 1 day and 6 hours prior to closest approach at their disposal.

The tracking stations following Rosetta in the past few days include ESA's 35m DSA 1 station at New Norcia, Australia, and NASA's DSN antennas at Goldstone, California and Robledo, near Madrid

Source: ESA - Rosetta - News

This post has been edited by Waspie_Dwarf: 05 November 2009 - 04:17 PM

[Waspie_Dwarf]

Follow Rosetta’s final Earth boost

Rosetta Flight Control Team during Steins encounter 2008

Credits: ESA/D. Scuka

4 November 2009
ESA’s comet chaser Rosetta will swing by Earth for the last time on 13 November to pick up energy and begin the final leg of its 10-year journey to comet 67P/Churyumov-Gerasimenko. ESA’s European Space Operations Centre will host a media briefing on that day.

This will be the third Earth swingby, the last of Rosetta’s four planetary gravity assists. Closest approach to Earth is expected at 08:45 CET (07:45 UT). The swingby will provide exactly the boost Rosetta needs to continue into the outer Solar System. The spacecraft is scheduled for a close encounter with asteroid 21 Lutetia in July next year, before it goes into hibernation early in 2011, only to wake up in early 2014 for approach to 67P/Churyumov-Gerasimenko.

As the most primitive objects in the Solar System, the chemical composition of comets has not changed much since their formation. They preserve a record of the early Solar System.


When it reaches 67P/Churyumov-Gerasimenko in 2014, Rosetta will be the first mission to orbit and deploy a lander on a comet. It will help to reconstruct the history of our neighbourhood in space.

The spacecraft is operated from ESOC, ESA’s European Space Operations Centre, Darmstadt, Germany.


RSVP requested

Media interested in following Rosetta’s last Earth swingby may participate in a press briefing organised at ESOC on 13 November.

• Time: 8:15 – 9:15 CET
  
• Location: ESA ESOC, Robert Bosch Strasse 5, Darmstadt, Germany

RSVP via telephone or email (contact details below) before 11 November 2009.


Those unable to attend can follow near-realtime updates on:

The Rosetta blog (esa.int/blog)
The ESA Rosetta website (esa.int/rosetta)
The ESA Spacecraft Operations website (esa.int/ops)

A timeline of critical events is available on the Rosetta website.


For more information:

Jocelyne Landeau-Constantin
Corporate Communication Office ESA/ESOC
Robert-Bosch-Strasse 5
D-64293 Darmstadt
Germany

Tel: +49 6151 90 25 46
Fax: +49 6151 902 961
Email: Andreas.Schepers @ esa.int

Source: ESA - Rosetta - News

[Waspie_Dwarf]

Rosetta approach on schedule

Artist view of ESA's Rosetta cometary probe.

Credits: ESA, image by AOES Medialab

6 November 2009
After the trajectory correction manoeuvre on 22 October, Rosetta has lined up on a near-perfect Earth approach path. The manoeuvre was so precise that mission controllers decided not to use the additional manoeuvre slot that was available yesterday.

Rosetta's orbit has been determined using radiometric data received from ESA and NASA ground stations, and estimates now show that she will pass within a few kilometres of the planned point of closest approach during next week’s Earth swingby. If necessary, additional manoeuvre slots are available at 24 and 6 hours prior to closest approach.

Rosetta is now forecast to pass over a watery point just South of the island of Java at an altitude of 2481 km at 13.34 km/s relative to Earth. This estimate will be updated in the coming days.

Science from a unique perspective

Though time will be short, several science observations are planned around the swingby to exploit Rosetta's unique perspective and powerful instrument suite.

The planned observations include imaging with the scientific camera system OSIRIS, an attempt to look for water on the Moon with MIRO, study of the magnetosphere with the suite of Rosetta plasma instruments, and observations of Earth's atmosphere and a search for aurorae.


The instruments will be turned on one-by one starting today and will stay on through the swingby.

The goal of the swingby is to assist Rosetta to ultimately reach Comet 67P/Churyumov-Gerasimenko for its prime mission. Accordingly, spacecraft operations will have priority over science activities on 13 November.

During the two nights before closest approach (13 November) and one night afterwards, members of the Rosetta team will conduct observations from ESA's Optical Ground Station in Tenerife, Spain. They will also carry out an experiment to investigate whether a laser beam can be detected by OSIRIS.


For more information:

Gerhard Schwehm, ESA Rosetta Mission Manager
Email: Gerhard.Schwehm @ esa.int

Rita Schulz, ESA Rosetta Project Scientist
Email: Rita.Schulz @ esa.int

Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager
Email: Andrea.Accomazzo @ esa.int

Source: ESA - Rosetta - News

[Waspie_Dwarf]

ESA's comet chaser Rosetta revisits Earth

After making its third and last Earth flyby in November 2009 to pick up extra speed, Rosetta will eventually arrive in the vicinity of Comet 67P/Churyumov-Gerasimenko in May 2014

Source: ESA Channel - YouTube

[Waspie_Dwarf]

ESA spacecraft may help unravel cosmic mystery

12 November 2009
When Europe's comet chaser Rosetta swings by Earth tomorrow for a critical gravity assist, tracking data will be collected to precisely measure the satellite's change in orbital energy. The results could help unravel a cosmic mystery that has stumped scientists for two decades.

Since 1990, scientists and mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they exchange with Earth during planetary swingbys. The unexplained variation is noticed as a tiny difference in speed gained or lost during the swingby when comparing that predicted by fundamental physics and that actually measured after the event.

Tiny unexplained speed variations

The unexplained speed variations are extremely small: NASA's Galileo satellite experienced an increase of just 3.9 mm/s above the expected value when it swung past Earth in December 1990. The largest unexpected variation - a boost of 13.0 mm/s - was observed with NASA's NEAR spacecraft at its Earth swingby in January 1998. On the other hand, variations seen at the swingbys of NASA's Cassini in 1999 and Messenger in 2005 were so small that they lay within the bounds of uncertainty.


ESTRACK New Norcia 35m
deep space antenna: tracking
Rosetta to detect unknown
speed anomaly

ESA's Rosetta has made two Earth swingbys, in 2005 and 2007. It too, experienced the strange anomaly. Frustratingly, Rosetta sped up by an unexplained 1.8 mm/s during the first passage, but experienced no slowing or speeding in 2007. No one knows what will happen on 13 November 2009 for Rosetta's third and last Earth swingby: scientists are stumped.

"It's a mystery as to what is happening with these gravity events. Some studies have looked for answers in new interpretations of current physics. If this proves correct, it would be absolutely ground-breaking news," says Trevor Morley, lead flight dynamics specialist working on Rosetta at ESOC, ESA's European Space Operations Centre, Darmstadt, Germany.


ESA researchers study Rosetta

Together with ESA colleague and orbital mechanics specialist Frank Budnik, Morley co-authored a scientific report in 2006 that studied the Rosetta anomaly during the 2005 swingby and listed possible causes.

These range from tidal effects peculiar to the near-Earth environment, atmospheric drag, or the pressure of radiation emitted or reflected by the Earth, to much more extreme possibilities, such as dark matter, dark energy or previously unseen variations in General Relativity, one of the most fundamental and well-tested theories of modern physics.


The Goldstone antenna in California - one of NASA's Deep Space
Network antennae

One American research team, led by ex-NASA scientist John Anderson, is even looking at the possibility that Earth's rotation may be distorting space-time - the fundamental fabric of our Universe - more than expected, thus affecting nearby spacecraft. But there is as yet no explanation how this could happen.

Before even considering such exotic explanations, all the usual causes of spacecraft speed errors have been thoroughly eliminated by numerous investigations conducted over the years at both ESA and NASA. Software bugs, calculation errors, tracking uncertainties and other, much more mundane, causes have all been systematically eliminated or accounted for, leaving the speed anomaly maddeningly unexplained.


NASA's Pionneer 10 & 11 similarly affected

Scientists at a number of universities and research centres in Europe, the US and Japan have worked on the anomaly problem over the past years. The Earth swingby anomaly has been compared to another unexplained anomaly - one experienced by NASA's Pioneer 10 and 11 spacecraft.

As they travel on trajectories that will take them eventually into interstellar space, both have experienced an unexpected acceleration directed toward the Sun, which has yet to be explained.


Watching through the night

At ESOC on 13 November, the mission control and flight dynamics teams will be watching closely as ESA's 35m New Norcia station in Australia tracks Rosetta during the closest approach, expected at 08:45:40.0 CET, followed - after a visibility gap of 20 minutes - by ESA's 15m Maspalomas station.

The tracking activity will generate highly precise data that will record whether the spacecraft speeds up or slows down more or less than expected. Deep space ground stations operated by NASA, at Canberra, Australia, and Goldstone, California, will also observe the spacecraft before and after closest approach.


Cassini-Huygens swings by Earth and accelerates towards Saturn

Credits: ESA

"We are using as many ground stations as are available to maximise the amount of swingby data we record. The more data we get, the better the chance that we may eventually come up with an answer," says Morley.

The data is keenly awaited by scientists on a number of continents, who are hoping to see whether the anomaly is present and whether an explanation is finally possible.


"As it stands now, no one knows what's behind this - it really is a mystery. And your prediction as to whether Rosetta will experience any swingby speed anomaly at all on 13 November is as good as anyone's," says Morley.

Source: ESA - Rosetta - News

[Waspie_Dwarf]

First view of Earth as Rosetta approaches home

12 November 2009
This spectacular image of our home planet was captured by the OSIRIS instrument on ESA's Rosetta comet chaser earlier today as the spacecraft approached Earth for the third and final swingby. Closest approach is due at 08:45 CET, 13 November 2009. Follow Rosetta's progress at ESA's dedicated Rosetta site and via the Rosetta Blog.

The image was acquired with the OSIRIS narrow-angle camera from a distance of 633 000 km on 12 November 2009 at 13:28 CET. The resolution is 12 km/pixel.

Three images with an orange, green, and blue filter were combined to create this one. The illuminated crescent is centered roughly around the South Pole (South at the bottom of the image). The outline of Antarctica is visible under the clouds that form the striking south-polar vortex. Pack ice in front of the coastline with its strong spectacular reflection is the cause for the very bright spots on the image.

The OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) is a wide-angle camera and a narrow-angle camera to obtain high-resolution images of the comet's nucleus and the asteroids that Rosetta passes on its voyage to Comet 67P/Churyumov-Gerasimenko. It will help in identifying the best landing sites.

Credits: ESA ©2009 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Principal Investigator: H.U. Keller, MPAe, Katlenburg-Lindau, Germany

Source: ESA - News

[Waspie_Dwarf]

Rosetta darting across the night

Rosetta darting across the night

13 November 2009
During the night of 12/13 November, scientists working at ESA's Optical Ground Station in Tenerife, Spain, conducted observations to view Rosetta as the satellite approached Earth.

The animation above comprises images recorded 13 November, 03:05 to 03:25. It comprises 18 images with an exposure time of 15 s and a separation of 69 s. The field is located in the constellation of Cetus and has a size of 10 x 10 arcmin. The telescope was tracking Rosetta so that the spacecraft appears as a dot in the centre of the image while the stars appear as stripes.

Last view before closest approach


Rosetta: the stripe in the centre

This image was captured at 03:59 CET, 13 November, with an exposure time of 2 minutes. The field is located in the constellation Cetus and spans 10 x 10 arcmin. The telescope was tracking the stars so that Rosetta appears as a stripe in the centre of the image while the stars appear as dots. Rosetta moves 3 arcminutes during the 2-minute exposure. Compare the movement with the image above, taken at 22:58 CET. The brightest star in the top left corner of the image has a magnitude of 12.

This is the last image taken before Rosetta's closest approach to Earth, immediately afterwards its elevation fell below 18 deg which is the limit of the telescope.

Rosetta: tiny dot in the centre


The dot in the centre is Rosetta

This still image was taken at 22:58 CET on 12 November. The total exposure time was 2 minutes. The field is located in the constellation of Cetus and has a size of 10 x 10 arcmin. Rosetta appears as a dot in the centre of the image while the stars appear as stripes. The stars move for almost 1 arcminute during the exposure. The brightest star in the bottom left corner of the images has a magnitude of 15.




Animation from 11/12 November



This excellent animation was created by stitching together a series of images captured 11/12 November.

The animation covers about 30 minutes and consists of images taken every 3 minutes, with an exposure time of 2 minutes. Rosetta moves roughly from East to West (North is up). The background stars are tracked, therefore Rosetta is seen as a short 'streak' line.


Additional observations 13/14 November

ESA scientists will be observing tonight as well, to see if they can detect detect Rosetta as it recedes. But the spacecraft will be much weaker in the sky than during the approach because an observer on ground will be looking at the unilluminated side of the solar arrays. Rosetta will have risen high enough for the telescope to point toward it at 04:30 CET. Its elevation will then increase; dawn starts shortly after 07:00 CET

Source: ESA - Rosetta - News

[Waspie_Dwarf]

Rosetta bound for outer Solar System after final Earth swingby

13 November 2009
This morning, mission controllers confirmed that ESA’s comet chaser Rosetta had swung by Earth at 8:45 CET as planned, skimming past our planet to pick up a gravitational boost for an epic journey to rendezvous with comet 67P/Churyumov-Gerasimenko in 2014.

Rosetta passed over the ocean, just South of the Indonesian island of Java, at exactly 08:45:40 CET, at a speed of 13.34 km/s with respect to Earth at an altitude of 2481 km. The swingby was pre-planned and fully automated, and the spacecraft was in direct communication with Earth at the time, via the ESA New Norcia Station.


Artist view of ESA's Rosetta cometary probe.

Credits: ESA, image by AOES Medialab

The successful swingby was confirmed at 09:05 CET when mission controllers re-established contact with Rosetta via ESA’s Maspalomas station in Spain. Although a detailed analyses is in progress, spacecraft operators have confirmed that the swingby provided a boost of 3.6 km/s.

Europe’s comet chaser has now flown a little over 4500 million km of its 7100 million km journey to its destination comet 67P/Churyumov-Gerasimenko. This was Rosetta’s fourth planetary swingby and the third and final swingby of Earth.

Science close to Earth


Image of the Earth acquired with the OSIRIS narrow-angle camera from a distance of 633 000 km on 12 November 2009 at 13:28 CET.

The resolution is 12 km/pixel.

The image is a part of a sequence of images taken every hour through one full rotation (24 hours). The movie will be published later.

Three images with an orange, green, and blue filter were combined to create this one. The illuminated crescent is centered roughly around the South Pole (South at the bottom of the image). The outline of Antarctica is visible under the clouds that form the striking south-polar vortex. Pack ice in front of the coastline with its strong spectacular reflection is the cause for the very bright spots on the image.

Credits: ESA ©2009 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Some of Rosetta’s instruments have been on since early November, performing imaging, magnetospheric, and atmospheric observations, as well as looking for water on the Moon. The first round of images and data recorded just before and during the swingby will be downloaded later today.

Rosetta is now departing Earth to meet asteroid (21) Lutetia in July 2010. It has gained sufficient orbital energy to achieve its final goal: a rendezvous with comet 67P/Churyumov-Gerasimenko in 2014. The spacecraft is scheduled to enter deep-space hibernation by mid 2011 for the coldest leg of her journey to receive a wake up call only in spring 2014.


For additional details on today’s swingby access the Rosetta Blog (esa.int/blog)


For more information:

Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager
Email: Andrea.Accomazzo @ esa.int

Gerhard Schwehm, ESA Rosetta Mission Manager
Email: Gerhard.Schwehm @ esa.int

Rita Schulz, ESA Rosetta Project Scientist
Email: Rita.Schulz @ esa.int

Source: ESA - Rosetta - News

[Waspie_Dwarf]

Rosetta sees a living planet

Closing in on home

13 November 2009
Images and data taken just before closest approach were downloaded this morning, and they show the lights of North America in the night and a glowing Southern Hemisphere.

As Rosetta approached Earth, OSIRIS periodically imaged the Earth once every hour for 24 hours. The images from the green optical colour filter have been combined into a movie sequence. The images were taken beginning when Rosetta was 1.1 million km from Earth, until it came 320 000 km close.



Illuminated crescent of Earth showing part of South America and Antarctica

The image above shows the illuminated crescent of Earth showing part of South America and Antarctica. This OSIRIS image was acquired with the the narrow-angle camera from a distance of 350 000 km at 22:28 UTC last night. The resolution is 6.5 km/pixel.


ESA's Rosetta sees North America at night

The lights of North American cities. Rosetta OSIRIS Imaging System's Narrow-Angle Camera image. The image was taken with a 10-s deep exposure at 05:44 CET. Some of the cities are clearly visible. Others like New York are covered by clouds, making the light diffuse.



Rosetta navigation camera image of Earth

A cloud-covered North America was captured at 14:03 UTC (15:03 CET), when Rosetta was at a distance of approximately 224 000 km from Earth's centre by Rosetta's navigation camera (navcam).

The navcam is used for precise determination of the orbit and optical visualisation. The output of the camera tells you where the centre of the object that is in the centre of the field of view is - it also gives physical parameters of the object.

The photos were taken to test the camera's operation with a large physical obejct. Previously, Steins was also imaged, but it is rather small (about 5 km across). Next year, the camera will be used to view Lutetia, which is much larger (about 95 km across). In the camera field of view, Lutetia shoudl appear about as large as the Earth looks in these images.

Source: ESA - Rosetta - News

[Waspie_Dwarf]

Swirling clouds over the South Pacific

Anticyclone over the South Pacific

17 November 2009
Rosetta's OSIRIS imaging system spotted an anticyclone over the South Pacific on the morning of 13 November. The images show the scene roughly as a human eye would see it.

Cloud structures over the South Pacific, seen with the OSIRIS Imaging System’s narrow-angle camera on 13 November at 06:48 CET. The clouds are part of an anticyclone that is visible close to the centre of the image below.

This false-colour composite was generated from the orange, green and blue optical colour filters. It depicts a portion of the scene below with five times the resolution.



Zooming out...

Taken three minutes before the image above, this image is shown in a logarithmic scale to bring out details in the varying light intensity. As a result the scene looks roughly the same as it would appear to the unaided human eye.


In greyscale

The same area in the South Pacific imaged with the orange filter of the narrow-angle camera and depicted in a logarithmic intensity scale.

Source: ESA - Rosetta - News