Rosetta is an ambitious ESA mission, launched in March 2004 from Kourou and which performed a rendezvous with comet 67/P Churyumov-Gerasimenko. Its lander, Philae, achieved landing on comet soil on the 12th November 2014 and performed 64 hours of science activities on its batteries before going into hibernation due to lack of solar energy.Philae is operated by the Lander Control Centre (LCC) at DLR Cologne Germany and the Science Operations and Navigation Centre (SONC) at CNES Toulouse France. The Lander system was provided by a European consortium (Germany, France, Italy, Hungary, Finland, UK, Ireland, Switzerland and Austria) and supports a scientific payload of 10 instruments.The Philae battery system was provided by CNES, it is composed of a Saft primary battery (1518Wh) and an ABSL secondary battery (151Wh). The primary is made of non-rechargeable LSH20 (LiSOCl2) Saft cells and the secondary of rechargeable ABSL Li-ion 18650HC.For the Philae mission, the energetic constraint was very important. Indeed, before launch, the operations had to be planned considering variability of several parameters (descent duration, communication slots, comet temperature, solar power availability, etc.). Since Rosetta launch, cells and batteries have been stored and specific ground test plans have been identified in order to follow the battery ageing and to validate the final Philae operation schedule. From ground test results, an electrical model of the batteries was developed to help the operations scheduling.During cruise, the operations consisted of secondary batteries monitoring and tests and primary battery conditioning. During separation and on-comet operations, the behaviour of the batteries system was checked and electric simulations helped with activities scheduling.Firstly, this paper will describe the Philae mission. In a second part, the batteries system will be presented. The ground strategy will be detailed. Finally, the operations of Philae batteries system will be described.

On the 12th of November 2014, The Rosetta Lander Philae became the first spacecraft to softly land on a comet nucleus. Due to the double failure of the cold gas hold-down thruster and the anchoring harpoons that should have fixed Philae to the surface, it spent approximately two hours bouncing over the comet surface to finally come at rest one km away from its target site. Nevertheless it was operated during the 57h of its First Science Sequence. The FSS, performed with the two batteries, should have been followed by the Long Term Science Sequence but Philae was in a place not well illuminated and fell into hibernation. Yet, thanks to reducing distance to the Sun and to seasonal effect, it woke up at end of April and on 13th of June it contacted Rosetta again. To achieve this successful landing, an intense preparation work had been carried out mainly between August and November 2014 to select the targeted landing site and define the final landing trajectory. After the landing, the data collected during on-comet operations have been used to assess the final position and orientation of Philae, and to prepare the wake-up. This paper addresses the Flight Dynamics studies done in the scope of this landing preparation from Lander side, in close cooperation with the team at ESA, responsible for Rosetta, as well as for the reconstruction of the bouncing trajectory and orientation of the Lander after touchdown.

This paper will present the way CNES 1 adapted its main contribution, the Science Operation and Navigation Centre (SONC), to all specificities of the mission, throughout all phases, from the Centre development before launch to the last science operations on the comet.The SONC was built step by step, permanently aiming at making easier its users 'life: Philae scientists, operators at SONC and at Lander Control Center (LCC), and even a part of the Rosetta community external to Philae.Most of the time parallel activities of development and operations took place within the 3 main SONC activities: data retrieval and processing, science operation scheduling and monitoring, lander flight dynamics.Size and skills of the SONC team evolved.At each step risks were assessed and decisions taken to limit it.Knowledge preservation was considered at different levels privileging as much as possible the continuity to the change.

Rosetta is an ambitious mission launched in March 2004 to study comet 67P/Churyumov–Gerasimenko. It is composed of a space probe (Rosetta) and the Philae Lander. The mission is a series of premieres: among others, first probe to escort a comet, first time a landing site is selected with short turnaround time, first time a lander has landed on a comet nucleus. In November 2014, once stabilized on the comet, Philae has performed its “First Science Sequence”. Philae’s aim was to perform detailed and innovative in-situ experiments on the comet’s surface to characterize the nucleus by performing mechanical, chemical and physical investigations on the comet surface. The main contribution to the Rosetta lander by the French space agency (CNES) is the Science Operation and Navigation Center (SONC) located in Toulouse. Among its tasks is the scheduling of the scientific activities of the 10 lander experiments and then to provide it to the Lander Control Center (LCC) located in DLR Cologne. The teams in charge of the Philae activity scheduling had to cope with considerable constraints in term of energy, data management, asynchronous processes and co-activities or exclusions between instruments. Moreover the comet itself, its environment and the landing conditions remained unknown until separation time. The landing site was selected once the operational sequence was already designed. This paper will explain the specific context of the Rosetta lander mission and all the constraints that the lander activity scheduling had to face to fulfill the scientific objectives specified for Philae. A specific tool was developed by CNES and used to design the complete sequence of activities on the comet with respect to all constraints. The baseline scenario for the lander operation will also be detailed as well as the sequence performed on the comet to highlight the difficulties and challenges that the operational team faced.

Rosetta is a Cornerstone Mission of the ESA Horizon 2000 programme [1,2]. In August 2014 it did rendezvous with comet 67P/Churyumov-Gerasimenko (CG) after a 10 year cruise. Both its nu-cleus and coma have been studied allowing the selec-tion of a landing site for Philae [3], the lander which successfully landed on the comet on November 12, 2014. It did, however, bounced off again and only came to rest after a leap of about 2 hours, approximate-ly one kilometer from the originally targeted site. Phi-lae was operational for almost 64 hours after separation and provided unique information from the surface of the comet. All ten instruments aboard could be operat-ed at least once. Descent and Landing: After injection of the Ro-setta spacecraft into the delivery orbit, Philae was ejected with a separation velocity of 18.76 cm/s on November 12th, 2014 at 8:35 UTC. This maneuver was performed perfectly, leading to a touch-down, about 7 hours later, at 15:34:04, only 51 seconds (!) before the precalculated landing time. The touch-down signal was received, the lander switched into the “on-comet mode” and started its first scientific sequence. However, the anchoring harpoons have not been fired and a cold gas system, intended to provide hold-down thrust could not be activated. Consequently, Philae bounced off the surface and was ballistically drifting above the comet surface. After 1:50 hours the Lander came to its final rest, after two more surface contacts. The Lander is now at a poorly illuminated location, the solar generator apparently provides power for only 1:20 hours per comet rotation. Fortunately communica-tions link with the Orbiter was possible very similar to the predicted time-slots. [4,5] Lander Search and Attempts for Re-activation: For the search of the lander and in order to re-construct the trajectory and bouncing, OSIRIS images (some of them showing the lander, shadow or footprints.), CONSERT ranging data, landing gear and solar gener-ator HK data as well as data from ROMAP, MUPUS, ROLIS and SESAME have been used. Consequently, the position and attitude of the Lander is fairly well determined, however it could not be identified on any of the OSIRIS NAC images, yet. Although Philae could not stay active after the bat-teries were depleted in November, there is a good chance for re-establishing contact, when comet and Lander are closer to the sun. A first attempt in March 2015 was not successful but by the time of the confer-ence (in June the heliocentric distance of 67P is only 1.45 AU, less than half as at the time of landing) we hope to be able to report on new data from Philae. Achnowledgements: 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 with additional contri-butions from Hungary, UK, Finland, Ireland and Aus-tria. References: [1] Glasmeier, K.-H., Bohnhardt, H., Koschny, D., Kuhrt, E. and Richter I., (2007) Space Science Rev. 128, pp. 1-21. [2] Biele, J. and Ulamec, S. (2008) Space Science Rev. 138, 275-289. [3] Ulamec, S. et al. (2015) Acta Astron., Vol. 107, pp. 79-86. [4] Ulamec, S. et al., Philae – First Landing on a Comet, 46th Lunar and Planetary Science Conference, abstract# 1121, Houston, 2015, [5] Biele, J. et al. The landing(s) of Philae and Inferences on Comet Surface Mechanical Properties, submitted to Science, 2015

Philae is a comet Lander, part of Rosetta which is a Cornerstone Mission of the ESA Horizon 2000 programme. Although Rosetta is not a low cost mission, the Lander, a contribution by an international consortium including scientific institutes, was provided with relatively moderate funding. Philae landed successfully on comet 67P/ Churyumov Gerasimenko on November 12, 2014. After several bounces Philae came to rest on the surface of the comet nucleus and sent back to Earth a plentitude of scientific data. All ten instruments of its payload have been operated at least once. Due to the fact that the Lander could not be anchored, the originally planned first scientific sequence had to be modified. The final landing area is not very well illuminated by the sun so that long term science operations had to be postponed to closer heliocentric distances. The paper will present the latest results on the anticipated re-activation of the Lander. 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 with additional contributions from Hungary, UK, Finland, Ireland and Austria.

Rosetta is an ambitious mission launched in March 2004 to study the nucleus as well as the coma of the comet 67P/Churyumov-Gerasimenko. It is composed of a space probe and the Philae Lander. The mission is a series of premieres: among others, first probe to escort a comet, first time a landing site is selected with a so short notice, first time a lander has landed on a comet nucleus. The space probe Rosetta reached the vicinity of the comet in spring 2014 when it has started to study Churyumov-Gerasimenko with remote sensing instruments. An intense observation phase followed to be able to select a landing site for the Lander. And in November 2014, at a distance of about 3 AU from the sun, Philae has reached its destination on the surface of the comet 67P. Once stabilized on the comet, the lander has performed its “First Science sequence”. Philae’s aim was to perform detailed and innovative in-situ experiments on the comet’s surface to characterize the nucleus by performing mechanical, chemical and physical investigations on the comet surface. The main contribution to the Rosetta lander by the French space agency (CNES) is the Science Operation and Navigation Centre (SONC) located in Toulouse. Among its tasks is the scheduling of the scientific activities of the 10 lander experiments and then to provide it to the Lander Control Centre (LCC) located in DLR Cologne. Nevertheless, the specific context of the Rosetta mission made this task even more complex if compared to usual spacecraft or landers: indeed the teams in charge of the Philae activity scheduling had to cope with huge constraints in term of energy, data management, asynchronous processes and co-activities or exclusions between instruments. In addition to these huge constraints it is important to note that the comet, its environment and the landing conditions remained unknown until the separation time and that the landing site was selected a short time before it had to take place and when the baseline operational sequence was already designed. This paper will explain the specific context of the Rosetta lander mission and all the constraints that the activity scheduling had to face to fulfil the scientific objectives specified for Philae. A specific tool was developed by CNES and used to design the complete sequence of activities on the comet with respect to all constraints. The baseline scenario designed this way will also be detailed to highlight the difficulties and challenges that the operational team had to face. A specific focus will be given on the landing site selection and the impacts on the scientific operations scheduling. Moreover the actual sequence performed on the comet will also be detailed and analysed to deduce the lessons that could be learned from such an unprecedented endeavour. Indeed as for every mission of exploration the flexibility concept was anticipated but had to face unexpected events.

Rosetta is a Cornerstone Mission of the ESA Horizon 2000 program. After rendezvousing with comet 67P/Churyumov-Gerasimenko in August 2014 and a 10 year cruise it started to study both its nucleus and coma with an orbiting spacecraft. The Lander, Philae, will land on November 12th and perform in-situ studies of the cometary material with a payload consisting of 10 scientific instruments.Rosetta and Philae have been in hibernation until January 20, 2014. After the successful wakeup they underwent a post-hibernation commissioning. The orbiter instruments (like e.g. the OSIRIS cameras, VIRTIS, MIRO, Alice and ROSINA) characterized the target comet and its environment to allow landing site selection and the definition of a separation, descent and landing (SDL) strategy for the Lander.By September 2014 our previously poor knowledge of the characteristics of the nucleus of the comet has increased drastically and the nominal and backup landing could be selected. The nominal site, as well as the corresponding descent strategy have been confirmed in mid-October, one month before the landing. The paper summarizes the selection process for a landing site and the planning for Separation-Descent-Landing (SDL). (C) 2014 IAA. Published by Elsevier Ltd. All rights reserved.

Rosetta is a Cornerstone Mission of the ESA Horizon 2000 programme. In August 2014 it reached comet 67P/Churyumov-Gerasimenko after a 10 year cruise. Both its nucleus and coma have been studied with its orbiter payload of eleven PI instruments, allowing the selection of a landing site for Philae. The landing on the comet nucleus successfully took place on November 12th, 2014. Philae touched the comet surface seven hours after ejection from the orbiter. After several bounces it came to rest and continued to send scientific data to Earth. All ten instruments of its payload have been operated at least once. Due to the fact that the Lander could not be anchored, the originally planned first scientific sequence had to be modified. Philae went into hibernation on November 15th, after its batteries ran out of energy. Re-activation of the Lander was expected for May/June 2015, when CG would be closer to the sun and, indeed, radio contact with the Lander was re-established on June 13th and for (so far) seven more occasions. 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 with additional contributions from Hungary, UK, Finland, Ireland and Austria.

Rosetta is an ambitious mission launched in March 2004 to study the nucleus as well as the coma of comet 67P/Churyumov-Gerasimenko. It is composed of a space probe and a Lander, Philae. The space probe will reach the vicinity of the comet in spring 2014 when it will start to investigate Churyumov-Gerasimenko with remote sensing instruments. Thanks to the obtained data the shape and density of the comet will be defined and an appropriate landing site will be selected, PHILAE lander will be the first equipment to land on a comet nucleus. This spectacular phase is expected to take place in November 2014 at a distance of about 3 AU from the sun. During its descent and once attached to the comet, the lander will begin its science mission. So it will perform detailed and innovative in-situ investigations on the comet’s surface to characterize the nucleus by performing mechanical chemical and physical investigations on comet surface. The French space agency (CNES) is contributing to the mission by providing the Science Operation and Navigation Centre (SONC) located in Toulouse. One of its tasks is to schedule and optimize the operational science activities of the 10 lander experiments and then to provide it to the Lander Control Center (LCC) located in DLR Cologne. Nevertheless the specific context of the Rosetta mission makes it more complex than for usual spacecraft or landers. Indeed the teams in charge of the Philae activity scheduling have to cope with huge constraints in term of energy, data management, asynchronous processes and co-activities or exclusions between instruments, ... In addition to these numerous constraints it is important to note that the comet and its environment will remain unknown until the delivery time and that the landing site will be selected a short time before landing. This paper will explain the specific context of the Lander mission and all the constraints that the activity scheduling has to face to fulfill the scientific objectives specified for PHILAE. A specific tool was developed by CNES and used to design the complete sequence of activities on the comet with respect to all the constraints. The current baseline scenario designed this way will also be detailed to highlight the difficulties and challenges that the operational team has to face. Moreover the example of an on-comet sequence will be used to highlight the fact that some activities might be modified and demonstrate how it is important to be prepared to this kind of adaptation during operations according to received information. Indeed as for every mission of exploration some unexpected events should happen and will induce a flexibility concept in the operations.

Recent planning for science and exploration missions has emphasized the high interest in the close investigation of small bodies in the Solar System. In particular in-situ observations of asteroids and comets play an important role in this field and will contribute substantially to our understanding of the formation and history of the Solar System.The first dedicated comet Lander is Philae, an element of ESA's Rosetta mission to comet 67/P Churyumov-Gerasimenko. Rosetta was launched in 2004. After more than 7 years of cruise (including three Earth and one Mars swing-by as well as two asteroid flybys) the spacecraft has gone into a deep space hibernation in June 2011. When approaching the target comet in early 2014, Rosetta will be re-activated. The cometary nucleus will be characterized remotely to prepare for Lander delivery, currently foreseen for November 2014.The Rosetta Lander was developed and manufactured, similar to a scientific instrument, by a consortium consisting of international partners. Project management is located at DLR in Cologne/Germany, with co-project managers at CNES (France) and ASI (Italy). The scientific lead is at the Max Planck Institute for Solar System Science (Lindau, Germany) and the Institut d'Astrophysique Spatiale (Paris).Mainly scientific institutes provided the subsystems, instruments and the complete, qualified lander system. Operations are performed in two dedicated centers, the Lander Control Center (LCC) at DLR-MUSC and the Science Operations and Navigation Center (SONC) at CNES. This concept was adopted to reduce overall cost of the project and is foreseen also to be applied for development and operations of future small bodies landers.A mission profiting from experience gained during Philae development and operations is MASCOT, a surface package for the Japanese Hayabusa 2 mission. MASCOT is a small (similar to 10 kg) mobile device, delivered to the surface of asteroid 1999JU3. There it will operate for about 16 h. During this time a camera, a magnetometer, a thermal monitor and an IR analytical instrument will provide ground truth and thus will even be able to support the selection of possible sampling sites for the main spacecraft.MASCOT is a flexible design that can be adapted to a wide range of missions and possible target bodies. Also the payload is flexible to some extent (with an overall mass in the 3 kg range). For example, the surface package is part of the optional strawman payload for MarcoPolo-R, a European asteroid sample return mission, proposed for ESA Cosmic Vision M-class. (C) 2013 IAA. Published by Elsevier Ltd. All rights reserved.

Two in-situ missions were launched at the end of 2011, soon after the 62nd LAC conference, one to Mars and the other to one of its moons, Phobos. The first - Mars Science Laboratory - has been developed by NASA and will take the largest ever rover, Curiosity, to the surface of Mars. The second mission, Phobos-Grunt under the responsibility of Roscosmos, will carry out orbital and in-situ experiments before sending Phobos samples to Earth. As of June 2012, MSL is on its way to Mars: landing is planned on August 6th, 2012 at 07 h 31 AM (French time). On the other hand, unfortunately, Phobos-Grunt fell back to Earth in an uncontrolled re-entry on January15th, 2012, after rocket burns intended to set the craft on a course for Mars had failed 2 months earlier, shortly after launch.CNES is privileged, together with French scientific laboratories from CNRS, to have contributed to both missions. More specifically, we participate in two MSL instruments:- The mast part of ChemCam (Chemistry Camera) which will analyse by spectrometry the plasma light emitted by Martian rocks after a laser shot. ChemCam-Mast Unit encompasses a laser, a telescope, a camera and the associated electronics.- The Gas Chromatograph (SAM-GC), one of the three SAM (Sample Analysis at Mars) instruments. SAM detects a wide range of organic components from the atmosphere and the ground. It will also search for carbon isotopes, as well as noble gas isotopes.French contributions to Phobos Grunt involve:- The Gas-Chromatograph (GC) and the Tunable Diode Laser Absorption Spectrometer (TDLAS) of the Gas Analytic Package (GAP) which will characterise the molecular soil composition.- The supply of two panoramic cameras (PANCAM), of a pair of stereoscopic cameras (STEREO PAIR), and of a visible microscope (MicrOmega VIS).- The IR spectral microscope (MicrOmega IR), a new instrument that will perform the first in-situ characterisation by microscopic spectral imaging of the mineralogical and molecular composition of a probably nondifferentiated body. This characterisation will be decisive in determining the origin of Phobos, and as a reference for the sample analyses.Before describing extensively these contributions and their objectives, the paper will put them into perspective by presenting previous French involvement in surface missions, in particular on Cassini-Huygens, and on Rosetta-Philae. We will then elaborate on future missions, by presenting our participation in the in-situ segment of the ESA-NASA ExoMars mission, in the DLR-CNES Mascot asteroid lander to be carried by JAXA's Hayabusa 2 spacecraft, and other candidate missions such as GEMS (Geophysical Monitoring Station, in the final list for NASA's Discovery programme to be definitely selected for realisation in 2012), and Selene 2. We will conclude by highlighting the synergy between these missions for the various instrument families. (C) 2012 Elsevier Ltd. All rights reserved.

Rosetta is a Cornerstone Mission of the ESA Horizon 2000 programme. It is going to rendezvous with comet 67P/Churyumov-Gerasimenko after a 10 year cruise and will study both its nucleus and coma with an orbiting spacecraft and a landed platform. The latter, named Philae, has been designed to land softly on the comet nucleus and is equipped with 10 scientific instruments to perform in-situ studies of the cometary material. Philae has been provided by a large international consortium.Rosetta was successfully launched on March 2, 2004 from Kourou in French Guyana. Philae is operated by the Lander Control Centre (LCC) at DLR, Cologne and the Science Operations and Navigation Centre (SONC) at CNES, Toulouse via the European Spacecraft Operations Centre (ESOC) in Darmstadt. The scientific lead is at the Max Planck Institute for Solar System Science (Katlenburg-Lindau, Germany) and the Institut d'Astrophysique Spatiale (Paris).Since launch, the Lander has been operational during commissioning, several checkouts, two planetary swing-bys at the Earth and one at Mars, fly-bys at asteroids Steins and Lutetia as well as some additional activities for calibration and failure investigation. Payload checkout PC13 was the last Lander activation prior to a deep space hibernation phase of Rosetta, which started in June 2011 and will last until approaching the comet in 2014.The paper describes the various Lander activities over the past seven years and gives an outlook of near- and on-comet operations. Landing is foreseen in November 2014 at a heliocentric distance of 3 AU. Prior to that, detailed characterization of the comet nucleus has to be performed with the Rosetta Orbiter instruments. (C) 2012 Elsevier Ltd. All rights reserved.