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Rosetta Project

Comet 67P. Photo ESA/OSIRIS
Comet on August 3, 2014. Distance to comet 285 km. Click for close-up. Photo ESA/OSIRIS
Comet 67P/Churyumov–Gerasimenko seen by Rosetta/OSIRIS on July 7, 2014. Rotation period 12.4 hours. Click on image to see high-resolution animation from 110 km distance

ESA's Comet Chaser Rosetta (link to ESA Rosetta Homepage)

Where exactly is Rosetta now? Click here for an on-line update

News: August 6, 20014: Rosetta finally reaches the comet and starts its actively controlled flight around it at a distance of about 100 km, mapping the surface and its near environment from all angles. The mapping trajectory insertion is expected for around 13:00 Finnish time. Distance to the comet is about 100 km, to the Sun about 540 million km or 3.6 AU. The complex shape shown in the animation above was recorded by Rosetta's on-board camera OSIRIS from a distance of about 20 000 km on July 7. The comet's rotation time is now refined to 12.4 hours with a size of about 5.4 km x 4 km. The microwave spectrometer MIRO measured a water production rate of about 1025 molecules/s or about 300 g per second. At the same time new refined values for the comet mass and therefore its density are expected. The surface temperature was measured by the VIRTIS instrument as -70° C

July 31, 2014: The solar panels of the Lander were confirmed to operate nominally. They will be crucial to provide Philae with energy after Landing and after the first 5 comet days' measurements have been performed with the help of the inbuilt non-rechargeable batteries.

April 24, 2014: The Philae Lander commissioning after the hibernation was successfully concluded. No major issues were identified. All instruments and subsystems are operational. During the interference tests between the radio communication system of the Lander and some of the instruments some distortions were observed. While SESAME/CASSE and DIM are not affected, the PP instrument is so much disturbed that a parallel operation of the radio link and PP will not be possible, leading to some re-structuring of the planned operations scenarios.

April 16, 2014: COSAC was activated successfully recording background gas spectra. SESAME continues to operate successfully. Only the interference test with the radio system is still missing, scheduled for next week. With the successful test of the EEPROM part of the Lander's Mass Memory, provided by FMI, the commissioning of this system element is successfully concluded.

April 15, 2014: Philae's camera Civa generated successfully its first images, the landing gear motor and the deployment motor of the APXS instrument were successfully moved. SESAME with FMI's PI-instrument PP performed successfully its first complete measurements after hibernation. All results are nominal without deviation from the status before hibernation.

Next days' activities: interference tests between instruments and the radio system, detailed memory tests of Philae's central computer.

April 10, 2014: The Rosetta orbiter system and instruments are now commissioned. No significant problems were found so far. Especially all Finnish contributions to the orbiter instruments were working well by the end of the commissioning phase on April 4.

During April 9 the first tests with the FMI-provided Lander mass memory were completed successfully. Further tests continue during the following 7 days. Also the integrity of the software included in the SESAME instrument with its FMI-contribution PP was successfully verified. All measured temperatures and currents were in the expected range. The correct operation of the Lander instruments and the Landing Gear mechanics will be tested during the following days until April 24.

Earlier reports:

On March 28 the Lander Philae was successfully switched on for the first time after hibernation. The updated control software was uploaded and successfully verified. All Lander system components tested so far are working nominally. The most important change in the software is the way how the harpoons will be fired after touch down, as during the past years a problem was detected with the reference model on ground. According to the new strategy both harpoons will be fired at the same time opposed to the initially planned sequential activation. The harpoons will anchor the Lander securely to the comet when drilling a hole for sample retrieval. Without anchoring the lander would be lifted in the low gravity environment rather than the drill entering the ground.

On March 27 the cameras on board Rosetta have caught a first glimpse of its destination comet since end of its hibernation phase in January.

The power levels and temperatures for orbiter and Lander are as expected and indicate that no deterioration of system components has happened during the 31 months hibernation phase. Also the solar panels do not show degradation in their performance. All reaction wheels needed for steering the spacecraft are operating nominally - good news as there were some indications before hibernation that one of the 4 units might develop a problem. The slight delay of the first contact on Monday was caused by an automatic rebooting of the on-board computer right after exiting the hibernation phase earlier during the day, delaying all subsequent activities somewhat. The reason is currently under investigation, but there is no impact on the further mission.

On January 2014 at 10:00 UTC Rosetta was programmed to exit the hibernation phase. After warming up of the star trackers and after the completion of a system self check the thrusters were fired at around 16:00 UTC to stop the satellite spinning. Using the sky images recorded with the system cameras and comparing them with stored star locations the spacecraft changed its orientation automatically such that it was getting maximum solar energy input via its solar arrays.  Then the large dish antenna was pointed towards Earth. With a signal travel time of about 45 minutes for the 673 million kilometer distance the first signal was received on Earth 18:17 UTC or 20:17 Finnish local time. ESA's control center ESOC in Darmstadt / Germany sent the first confirmation commands to the spacecraft terminating the autonomous contact phase. Since then several data packages have been exchanged between ESOC and the satellite. Detailed technical information received via telemetry during the night and the early morning hours of January 21 indicate that the most important system parameters of orbiter and Lander are nominal and as expected.

Animations of the wake-up process generated by the ESA team can be found via the ESA Rosetta home page

The complete orbit history is displayed in this 9 MB AVI-animation.

Rosetta and Finland:

Rosetta was Finland's first major space science project after it joined ESA as full member in 1995. With the orbiter structure built by Patria, Tampere, and FMI's participation in 6 different instruments on board the orbiter and Lander, this was a major effort involving several Finnish companies. Strengthening the international cooperation to the major European players in the space sector this placed Finland firmly onto the European map as a thought-after partner in joined space technology ventures. In the subsequent years several Finns held high-ranking positions of trust in the European space community.

Rosetta entered hibernation:

On June 8 2011 at 07:30 UTC Rosetta was spun-up to stabilise its attitude in view of the hibernation mode.The spacecraft behaviour, as far as we could monitor, was excellent and allowed the flight control team at ESOC in Darmstadt to release the command to enter hibernation mode later in the afternoon. The last RF pulse from the spacecraft was detected at ca. 14:12:00 UTC as expected and after that no further signal could be seen from the spacecraft thus confirming a successful hibernation entry.

Presentation of Rosetta Payload (FMI) large (47MB PDF)smaller (21,5MB PDF)

 

FMI's contributions to the Rosetta Lander Philae:

The Permitivity Probe PP as part of Philae's instrument group SESAME; Principle Investigator: Walter Schmidt, FMI

 

The autonomous Mass Memory of Philae's Central Data Management System CDMS

 

FMI's contributions to the Rosetta orbiter:

The dust spectrometer COSIMA

The Langmuir Probe LAP as part of the Rosetta Plasma Consortium (RPC)

The Ion Composition Analyzer ICA as part of the Rosetta Plasma Consortium (RPC)

The Multi Impedance Probe MIP (home page in French) as part of the Rosetta Plasma Consortium. FMI provided the Electrical Ground Support Equipment (EGSE) for instrument development support.

 FMI supports the Rosetta project via extensive data analysis and modelling efforts, mainly concentrating on the plasma- and dust environment of the comet. This activity is funded by a grant from the Finnish Academy of Sciences


Acknowledgements:

 

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander to its surface. Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust, and organic materials associated with the comet, via both remote and in-situ observations, the Rosetta mission should become the key to unlocking the history and evolution of our Solar System, as well as answering questions regarding the origin of Earth's water and perhaps even life.

SESAME is an experiment on the Rosetta lander Philae. It consists of three instruments CASSE, DIM and PP, which were provided by a consortium comprising DLR, MPS, FMI, MTA, FHG, Univ. Cologne,  LATMOS and ESTEC.

The financial support of the Finnish instrument contributions by the Finnish Funding Agency for Innovation (TEKES),  the Academy of Finland and the Finnish Meteorological Institute are gratefully acknowledged.