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1. Rosetta CONSERT Data as a Testbed for In Situ Navigation of Space Probes and Radiosciences in Orbit/Escort Phases for Small Bodies of the Solar System

Author

Mao Ye, Fei Li, Jianguo Yan, Alain Hérique, Wlodek Kofman, Yves Rogez, Thomas P. Andert, Xi Guo, and Jean-Pierre Barriot

Subjects
comet, 67P/C-G, CONSERT, navigation, ranging, solar system small bodies, Science
Abstract

Many future space missions to asteroids and comets will implement autonomous or near-autonomous navigation, in order to save costly observation time from Earth tracking stations, improve the security of spacecraft and perform real-time operations. Existing Earth-Spacecraft-Earth tracking modes rely on severely limited Earth tracking station resources, with back-and-forth delays of up to several hours. In this paper, we investigate the use of CONSERT ranging data acquired in direct visibility between the lander Philae and the Rosetta orbiter, in the frame of the ESA space mission to comet 67P/Churyumov-Gerasimenko, as a proxy of autonomous navigation and orbitography science capability.

Published
2021
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3. SPRATS: a versatile Simulation and Processing RAdar ToolS for planetary missions

Author

Wlodek Kofman, Petit-Prince Ludimbulu, Yves Rogez, Alain Herique, Oriane Gassot, and Sonia Zine

Subjects
Synthetic aperture radar, Earth observation, Process (engineering), law, Remote sensing (archaeology), Computer science, Asteroid, SIGNAL (programming language), Systems engineering, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Radar, law.invention
Abstract

Our knowledge of the internal structure of asteroids is currently indirect and relies entirely on inferences from remote sensing observations of the surfaces. Radar observation of asteroids is the most mature technique available in order to characterize their structure, which is fundamental for understanding the small bodies' history and for planetary defense missions. However, as the small bodies' geometry is complex, simulation of the radar design and the signal is required in order to assess the instrument performance and thus the mission science return. SPRATS is a software package designed for mission and operation analysis for planetary bodies. It provides the tools to evaluate the radar concepts and mission scenarios, evaluate the processing performances, validate data processing techniques on the final data, and process real radar data when facing complex geometries different from the Earth observation geometry. The paper presents the architecture of the SPRATS toolbox along with relevant examples to illustrate its interest.

Published
2020
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4. Low Frequency Radar (LFR) on the JUVENTAS CubeSat for HERA / ESA mission

Author

Hannah Goldberg, Alain Herique, Dirk Plettemeier, Wlodek Kofman, and Yves Rogez

Subjects
Physics, CubeSat, HERA, Low-frequency radar, Remote sensing
Abstract

The Low Frequency Radar (LFR) on the JUVENTAS CubeSat for HERA / ESA mission to Didymos Binary Asteroid is a unique opportunity to perform direct measurements of its internal structure and regolith. LFR has been developed to fathom asteroid from a small platform. This instrument is inherited from CONSERT/Rosetta and has been redesigned in the frame of the AIDA and HERA ESA mission.Onboard JUVENTAS, LFR is operating in monostatic mode to probe down to the first hundreds of meters into the subsurface and to achieve a full tomography of the Didymos' moonlet. Direct observations of the internal structure of asteroids can solve still open basic questions like: Is the body a monolithic piece of rock or a rubble-pile? How high is the porosity? What is the typical size of the constituent blocks? Are these blocks homogeneous or heterogeneous? How is the regolith covering its surface constituted?The low frequency aboard the Juventas CubeSat will contribute to the solution of these open and for planetary defense crucial questions.- The first LRF objective is the characterization of the moonlet interior, to identify internal structure and to analyze the size distribution and heterogeneity of constitutive blocks from sub metric to global- The second objective is the estimation of average permittivity and mapping of its spatial variation especially in the crater area.- The same characterization applied to the main of the binary system is among secondary objectives.- Supporting shape modeling and determination of the dynamical state by radar ranging is a further secondary objective.This paper will present the instrument concept and measurement strategy, its performances and the expected science return.

Published
2020
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5. MASCOT2 – A small body lander to investigate the interior of 65803 Didymos′ moon in the frame of the AIDA/AIM mission

Author

Dirk Plettemeier, Jens Biele, Ian Carnelli, Michael Küppers, Silvio Schröder, Christian Grimm, Jesus Gil Fernandez, Jan Thimo Grundmann, Oliver Küchemann, Jerzy Grygorczuk, Josef Reill, Andres Galvez, Yves Rogez, Christian Krause, Christian Philippe, Elisabet Wejmo, Stephan Ulamec, Simon Tardivel, Caroline Lange, Tra-Mi Ho, Barbara Cozzoni, B. Grieger, Christian Ziach, Marta Tokarz, Alain Herique, and Michael Lange

Subjects
010504 meteorology & atmospheric sciences, Spacecraft, Computer science, business.industry, Interface (computing), Frame (networking), Aerospace Engineering, Accelerometer, 01 natural sciences, law.invention, Deflection (ballistics), MASCOT2 lander asteroid AIDA, Asteroid, law, 0103 physical sciences, Radar, Aerospace engineering, business, Low-frequency radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

In the frame of Near-Earth-Object exploration and planetary defence, the two-part AIDA mission is currently studied by NASA and ESA. Being composed of a kinetic impactor, DART (NASA), and by an observing spacecraft, AIM (ESA), AIDA has been designed to deliver vital data to determine the momentum transfer efficiency of a kinetic impact onto a small body and the key physical properties of the target asteroid. This will enable derivation of the impact response of the object as a function of its physical properties, a crucial quantitative point besides the qualitative proof of the deflection. In the course of the AIM mission definition, a lander has been studied as an essential element of the overall mission architecture. It was meant to be deployed on Didymoon, the secondary body of the binary NEA system 65803 Didymos and it was supposed to significantly enhance the analysis of the body's dynamical state, mass, geophysical properties, surface and subsurface structure. The mission profile and the design of the 13 kg (current best estimate) nano-lander have been derived from the MASCOT lander flying aboard Hayabusa2. Differing from its predecessor by having an increased lifetime of more than three months, a surface mobility capability including directed movement, a sensor system for localization and attitude determination on the surface and a redesigned mechanical interface to the mother spacecraft. The MASCOT2 instrument suite consists of a bi-static, low frequency radar as main instrument, supported by an accelerometer, a camera, a radiometer and a magnetometer; the latter three already flying on MASCOT. Besides the radar measurements, the camera is meant to provide high-resolution images of the landing area, and accelerometers to record the bouncing dynamics by which the top surface mechanical properties can be determined. During the DART impact, MASCOT2 was expected to be able to detect the seismic shock, providing valuable information on the internal structure of the body. MASCOT2 was supposed also to serve as a technology demonstrator for very small asteroid landing and extended operations powered by a solar generator. In this paper, we describe the science concept, mission analysis of the separation, descent and landing phase, the operational timeline, and the latest status of the lander's design. Despite the fact that AIM funding has not been fully confirmed during the ESA Ministerial conference in 2016, MASCOT2 is an instrument package of high maturity and major interest for planetary defence and NEO science. With appropriate tailoring and optimization, it can be considered and studied for future missions.

Published
2018
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6. Rosetta CONSERT Data as a Testbed for In Situ Navigation of Space Probes and Radiosciences in Orbit/Escort Phases for Small Bodies of the Solar System

Author

Wlodek Kofman, Jianguo Yan, Yves Rogez, Thomas Andert, Xi Guo, Fei Li, Alain Herique, Jean-Pierre Barriot, and Mao Ye

Subjects
Spacecraft, business.industry, Computer science, Science, solar system small bodies, Comet, Ranging, ranging, 67P/C-G, Space exploration, law.invention, Orbiter, comet, law, Asteroid, CONSERT, navigation, Orbit (dynamics), General Earth and Planetary Sciences, Aerospace engineering, business, Visibility
Abstract

Many future space missions to asteroids and comets will implement autonomous or near-autonomous navigation, in order to save costly observation time from Earth tracking stations, improve the security of spacecraft and perform real-time operations. Existing Earth-Spacecraft-Earth tracking modes rely on severely limited Earth tracking station resources, with back-and-forth delays of up to several hours. In this paper, we investigate the use of CONSERT ranging data acquired in direct visibility between the lander Philae and the Rosetta orbiter, in the frame of the ESA space mission to comet 67P/Churyumov-Gerasimenko, as a proxy of autonomous navigation and orbitography science capability.

Published
2021
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7. Reconstruction of the flight and attitude of Rosetta's lander Philae

Author

Christoph Statz, Philip Heinisch, Martin Hilchenbach, Ronny Hahnel, Felix Finke, Holger Sierks, Dirk Plettemeier, Wlodek Kofman, Karl-Heinz Glassmeier, Yves Rogez, Hans-Ulrich Auster, Eric Jurado, Romain Garmier, Carsten Güttler, Thierry Martin, Ingo Richter, and Alain Herique

Subjects
010504 meteorology & atmospheric sciences, Comet, Aerospace Engineering, Touchdown, Geodesy, Collision, 01 natural sciences, law.invention, Data link, Orbiter, Radio tracking, law, 0103 physical sciences, Trajectory, Descent (aeronautics), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

Since Rosetta's lander Philae touched down on comet 67P/Churyumov-Gerasimenko on November 12, 2014, many tools have been applied to reconstruct Philae's flight path and attitude between separation, the touchdowns, collision and the final landing at Abydos. In addition to images from the cameras onboard both orbiter and lander (“OSIRIS”, “CIVA” and “ROLIS”), radio tracking results, solar array and radio data link housekeeping data, one of the major sources for timing and attitude information were two point magnetic field measurements by the magnetometers “ROMAP” and “RPC-MAG” aboard Philae and Rosetta. In this study all the different results are combined to determine in further detail what happened to Philae during its travel above the surface of 67P/Churyumov-Gerasimenko. In addition to a description of the descent dynamics and the attitude during rebound, the approximate coordinates for the collision at 16:20 UTC with the rim of the Hatmehit crater and the second touchdown are estimated. It is also shown, that Philae did not change attitude between the end of the first-science sequence and September 2, 2016.

Published
2017
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8. The interior of Comet 67P/C-G; revisiting CONSERT results with the exact position of the Philae lander

Author

Sonia Zine, Alain Herique, Yves Rogez, Wlodek Kofman, Anny Chantal Levasseur-Regourd, Laurent Jorda, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Astronomy, radar astronomy -comets, Astronomy and Astrophysics, 67P/Churyumov–Gerasimenko, Radar astronomy, 01 natural sciences, general -comets, 13. Climate action, Space and Planetary Science, Position (vector), [SDU]Sciences of the Universe [physics], 0103 physical sciences, Comets, individual, techniques, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

CONSERT, a bistatic radar onboard the Rosetta spacecraft and its Philae lander, was designed to probe the nucleus of comet 67P/Churyumov–Gerasimenko with radio waves at 90 MHz frequency. In 2016 September, the exact position of Philae was retrieved, within the region previously identified by CONSERT. This allowed us to revisit the measurements and improve our analysis of the properties of the interior, the results of which we present here. The relative permittivity of the materials is found to range from about 1.7 to 1.95 in the shallow subsurface (

Published
2020
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9. The search campaign to identify and Image the Philae Lander on the surface of comet 67P/Churyumov-Gerasimenko

Author

J.L. Pellon, Antoine Charpentier, V. Companys, J. P. Bibring, Norbert I. Kömle, Wlodek Kofman, Alain Herique, Romain Garmier, Michael Küppers, Carsten Güttler, Michael Maibaum, B. Grieger, Matthew Taylor, Holger Sierks, Mario Salatti, P. Gutierrez-Marques, Koen Geurts, P. Muñoz, Yves Rogez, Jakob Deller, A. Accomazzo, S. Mckenna Lawlor, S. Lodiot, Bernhard Geiger, Laurence O'Rourke, Philippe Gaudon, C. Bielsa, Stephan Ulamec, R. Andres, Valentina Lommatsch, Joelle Durand, P. Martin, Cecilia Tubiana, and Elsevier, Ltd

Subjects
020301 aerospace & aeronautics, Comet, Comet 67P, Aerospace Engineering, Touchdown, 02 engineering and technology, 01 natural sciences, Astrobiology, Nutzerzentrum für Weltraumexperimente (MUSC), 0203 mechanical engineering, 0103 physical sciences, Philae Lander, 010303 astronomy & astrophysics, Geology, Churyumov-Gerasimenko
Abstract

On the 12th of November 2014, the Rosetta Philae Lander descended to make the first soft touchdown on the surface of a comet – comet 67P/Churyumov- Gerasimenko. That soft touchdown did occur but due to the failure in the firing of its two harpoons, Philae bounced and travelled across the comet making contact with the surface twice more before finally landing in a shaded rocky location somewhere on the southern hemisphere of the comet. The search campaign, led by ESA, involved multiple teams across Europe with a wide range of techniques used in support of it. This search campaign would continue through 2015 where a prime candidate on the surface was identified and on into 2016 to end on the 2nd of September 2016 when a definitive and conclusive image was taken of the lander on the surface of the comet, confirming the prime candidate to indeed be Philae.

Published
2019

10. Direct Observations of Asteroid Interior and Regolith Structure: Science Measurement Requirements

Author

Jan Thimo Grundmann, Jens Biele, Stephan Ulamec, B. Grieger, Oriane Gassot, Yasumasa Kasaba, Antonella Barucci, Dirk Plettemeier, Erik Asphaug, Petr Schaffer, Valérie Ciarletti, Marco Delbo, Julie Bellerose, Wenzhe Fa, Jérémie Lasue, Sonia Zine, Ian Carnelli, Alain Herique, Roberto Orosei, Patrick Michel, Pierre Beck, Michael Küppers, Wlodek Kofman, J. Du, J. Gil Fernandez, R. RodriguezSuquet, Jerzy Grygorczuk, B. Agnus, Martin Laabs, R. Granados-Alfaro, J. C. Souyris, Christian Krause, Christelle Eyraud, Naomi Murdoch, Özgür Karatekin, Marta Tokarz, C. Buck, Anny Chantal Levasseur-Regourd, Essam Heggy, P. W. Bousquet, X. Du, Juergen Oberst, Colin Snodgrass, Caroline Lange, Stefano Mottola, Marco Mutze, A. Cheng, Lorenzo Bruzzone, Atsushi Kumamoto, Yves Rogez, S. Rochat, Simon F. Green, Alfred Mallet, T. Kobayashi, Ronny Hahnel, Jan-Erik Wahlund, Tra-Mi Ho, Lydie Bonal, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Centre National d'Études Spatiales [Toulouse] (CNES), University of Trento [Trento], European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Peking University [Beijing], Technische Universität Dresden = Dresden University of Technology (TU Dresden), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), HIPE (HIPE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Planetary and Space Sciences [Milton Keynes] (PSS), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU)-Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), European Space Astronomy Centre (ESAC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), ASTRONIKA Sp. Zo.o., USC Viterbi School of Engineering, University of Southern California (USC), Royal Observatory of Belgium [Brussels] (ROB), Tohoku University [Sendai], Korea Institute of Geoscience and Mineral Resources, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Technical University of Berlin / Technische Universität Berlin (TU), Istituto di Radioastronomia [Bologna] (IRA), Istituto Nazionale di Astrofisica (INAF), Institut für Nachrichtentechnik [Dresden] (IfN), Swedish Institute of Space Physics [Uppsala] (IRF), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Agence Spatiale Européenne (ESA), IMPEC - LATMOS, Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Dresden (TUD), Royal Observatory of Belgium [Brussels], Polska Akademia Nauk (PAN), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Technische Universität Berlin (TUB), Istituto di Radioastronomia (IRA), The Open University [Milton Keynes] (OU), California Institute of Technology (CALTECH)-NASA, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), ITA, USA, GBR, FRA, DEU, BEL, KOR, JPN, NLD, POL, CHN, SWE, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Technische Universität Berlin (TU)

Subjects
Radar tomography, Atmospheric Science, Solar System, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Aerospace Engineering, 01 natural sciences, Astrobiology, law.invention, Gravitational field, law, Asteroid deep internal structure, Asteroid regolith, Dielectric properties, Near-earth asteroid, Space and Planetary Science, Near-Earth Asteroid, 0103 physical sciences, Radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Near-Earth object, [SCCO.NEUR]Cognitive science/Neuroscience, Neurosciences, Astronomy and Astrophysics, Regolith, Accretion (astrophysics), Depth sounding, Geophysics, Asteroid, Radar Tomography, General Earth and Planetary Sciences, Geology
Abstract

International audience; Our knowledge of the internal structure of asteroids is, so far, indirect – relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling of formation and evolution. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape asteroid internal structures? Is the composition and size distribution observed on the surface representative of the bulk? These questions are crucial to understand small bodies’ history from accretion in the early Solar System to the present, and direct measurements are needed to answer these questions for the benefit of science as well as for planetary defense or exploration.Radar is one of the main instruments capable of sounding asteroids to characterize internal structure from sub-meter to global scale. In this paper, we review the science case for direct observation of the deep internal structure and regolith of a rocky asteroid of kilometer size or smaller. We establish the requirements and model dielectric properties of asteroids to outline a possible instrument suite, and highlight the capabilities of radar instrumentation to achieve these observations. We then review the expected science return including secondary objectives contributing to the determination of the gravitational field, the shape model, and the dynamical state. This work is largely inherited from MarcoPolo-R and AIDA/AIM studies.

Published
2018
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11. The CONSERT operations planning process for the Rosetta mission

Author

B. Grieger, Bernhard Geiger, Laurence O'Rourke, Alejandro Blazquez, Michael Maibaum, Jens Biele, Michael Küppers, Dirk Plettemeier, Koen Geurts, Yves Rogez, Stephan Ulamec, Alain Herique, Marc Costa Sitjà, Ronney Hahnel, M. Barthelemy, Armelle Hubault, Wlodek Kofman, Claire Vallat, Pascal Puget, Raymond Hoofs, Jean-François Fronton, Cinzia Fantinati, Cedric Delmas, Pablo Muñoz, Brigitte Pätz, Eric Jurado, Mike Ashman, Aurélie Moussi-Souffys, Sonia Zine, Nicolas Altobelli, and Carlos M. Casas

Subjects
Engineering, 010504 meteorology & atmospheric sciences, Spacecraft, Computer science, business.industry, Comet, Aerospace Engineering, Method, 01 natural sciences, Philae, Nutzerzentrum für Weltraumexperimente (MUSC), Planning process, Planning, Rosetta Mission, Comet nucleus, 0103 physical sciences, Rosetta, Systems engineering, CONSERT, Aerospace engineering, business, 010303 astronomy & astrophysics, Simulation, Operation, 0105 earth and related environmental sciences
Abstract

In the scope of European Space Agency's Rosetta mission, the COmet Nucleus Sounding Experiment by Radio wave Transmission (CONSERT) has sounded the deep interior of the nucleus of comet 67P/Churyumov-Gerasimenko. The CONSERT experiment main objective was to image the interior of the comet nucleus. This bi-static radar experiment with instrument units on-board both, the Rosetta main spacecraft and its lander Philae, requires a specific geometric configuration to operate and produce fruitful science data. Thus, these geometric constraints involve mainly the position and orientation of Rosetta and Philae. From the operations planning point of view, the mission constraints imposed observation slots to be defined far before their execution, while the comet shape, spacecraft trajectories and landing site were still unknown. The CONSERT instrument operations scheduling had to be designed jointly for Rosetta and Philae platforms, based on different time scales and planning concepts. We present the methods and tools we developed to cope with the complexity of this planning process. These operations planning concepts allowed handling the complexity of multiple platform operations and the lack of prior knowledge of the observed target.

Published
2016
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12. Rosetta lander Philae: Flight dynamics analyses for landing site selection and post- landing operations

Author

P. Heinish, Emile Remetean, Jean-François Crifo, Romain Garmier, Alain Herique, Alejandro Blazquez, Jens Biele, Laurent Jorda, Eric Jurado, Elisabet Canalias, Cedric Delmas, Philippe Gaudon, Yves Rogez, B. Dolives, Vladimir Zakharov, Stephan Ulamec, Julien Laurent-Varin, A.V. Rodionov, Alex Torres, Wlodek Kofman, Thierry Martin, Jean-Baptiste Vincent, Thierry Ceolin, Centre National d'Études Spatiales [Toulouse] (CNES), CS-Systèmes d'Information [Toulouse] (CS-SI), German Aerospace Center (DLR), Magellium SAS, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Russian Federal Nuclear Center (RFNC-VNIIEF), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Max-Planck-Institut für Sonnensystemforschung (MPS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), HEPPI - LATMOS, and Technische Universität Braunschweig [Braunschweig]

Subjects
010504 meteorology & atmospheric sciences, Comet, Site selection, Trajectory, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Aerospace Engineering, 01 natural sciences, Flight Dynamics, Flight dynamics, Aeronautics, Comet nucleus, 0103 physical sciences, Rosetta, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Landing, Spacecraft, business.industry, Touchdown, Philae, Nutzerzentrum für Weltraumexperimente (MUSC), [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Target site, Attitude, business, Geology
Abstract

International audience; 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 57 hours 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.

Published
2016
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13. Rosetta rendezvous and CONSERT operations in 2014: A chimeric surface model of 67P/Churyumov Gerasimenko

Author

Alain Herique, Sonia Zine, Wlodek Kofman, Yves Rogez, and Jérémie Lasue

Subjects
Surface (mathematics), Physics, Comet, Rendezvous, Astronomy and Astrophysics, computer.software_genre, law.invention, Simulation software, Depth sounding, Orbiter, Space and Planetary Science, law, Comet nucleus, Radar, computer, Remote sensing
Abstract

In 2014 the European Space Agency's Rosetta probe will rendezvous with the comet 67P/Churyumov Gerasimenko (67P) and the Philae Lander will land on the surface of the nucleus. Following the landing, the COmet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) radar will perform the tomography of the nucleus by measuring radiowave propagation through the comet between the Lander and the orbiter. Preparation for these operations, in particular the development and validation of simulation software, requires a shape model of the surface of 67P. The complexity of this model should reflect the environmental conditions that will be found in 2014. In this paper, we show that existing models of 67P are not of a sufficiently high resolution to constitute interesting test cases. Following a review of current shape models for other comets, we propose a composite which is a hybrid of the 67P and 81P/Wild 2 models.

Published
2012
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14. COMETARY SCIENCE. Properties of the 67P/Churyumov-Gerasimenko interior revealed by CONSERT radar

Author

Wlodek, Kofman, Alain, Herique, Yves, Barbin, Jean-Pierre, Barriot, Valérie, Ciarletti, Stephen, Clifford, Peter, Edenhofer, Charles, Elachi, Christelle, Eyraud, Jean-Pierre, Goutail, Essam, Heggy, Laurent, Jorda, Jérémie, Lasue, Anny-Chantal, Levasseur-Regourd, Erling, Nielsen, Pierre, Pasquero, Frank, Preusker, Pascal, Puget, Dirk, Plettemeier, Yves, Rogez, Holger, Sierks, Christoph, Statz, Hakan, Svedhem, Iwan, Williams, Sonia, Zine, and Jakob, Van Zyl

Abstract

The Philae lander provides a unique opportunity to investigate the internal structure of a comet nucleus, providing information about its formation and evolution in the early solar system. We present Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) measurements of the interior of Comet 67P/Churyumov-Gerasimenko. From the propagation time and form of the signals, the upper part of the "head" of 67P is fairly homogeneous on a spatial scale of tens of meters. CONSERT also reduced the size of the uncertainty of Philae's final landing site down to approximately 21 by 34 square meters. The average permittivity is about 1.27, suggesting that this region has a volumetric dust/ice ratio of 0.4 to 2.6 and a porosity of 75 to 85%. The dust component may be comparable to that of carbonaceous chondrites.

Published
2015

15. Properties of the 67P/Churyumov-Gerasimenko interior revealed by CONSERT radar

Author

Jean Pierre Goutail, Alain Herique, Charles Elachi, Holger Sierks, Pascal Puget, Jérémie Lasue, Laurent Jorda, Yves Rogez, Wlodek Kofman, Dirk Plettemeier, Christoph Statz, Iwan P. Williams, Christelle Eyraud, Pierre Pasquero, Stephen M. Clifford, Frank Preusker, Håkan Svedhem, Jakob van Zyl, Essam Heggy, Jean-Pierre Barriot, Valérie Ciarletti, Yves Barbin, Erling Nielsen, Peter Edenhofer, Sonia Zine, Anny Chantal Levasseur-Regourd, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Géopôle du Pacifique Sud (GePaSUD), Université de la Polynésie Française (UPF), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Institute [Houston] (LPI), Department of Electrical Engineering Information Technology [Bochum], Ruhr-Universität Bochum [Bochum], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), HIPE (HIPE), Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Southern California (USC), USC Viterbi School of Engineering, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institute of Planetary Research, German Aerospace Center (DLR), Technische Universität Dresden = Dresden University of Technology (TU Dresden), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Queen Mary University of London (QMUL), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Laboratoire de Géosciences du Pacifique Sud (GePaSUD), IMPEC - LATMOS, California Institute of Technology (CALTECH)-NASA, Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Technische Universität Dresden (TUD), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Propagation time, Solar System, 67P, Multidisciplinary, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Geophysics, Philae, law.invention, Astrobiology, comet interior, Depth sounding, comet, 13. Climate action, Chondrite, law, Comet nucleus, CONSERT, Radar, Geology, Radio wave
Abstract

International audience; The Philae lander provides a unique opportunity to investigate the internal structure of a comet nucleus, providing information about its formation and evolution in the early solar system. We present Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) measurements of the interior of Comet 67P/Churyumov-Gerasimenko. From the propagation time and form of the signals, the upper part of the “head” of 67P is fairly homogeneous on a spatial scale of tens of meters. CONSERT also reduced the size of the uncertainty of Philae’s final landing site down to approximately 21 by 34 square meters. The average permittivity is about 1.27, suggesting that this region has a volumetric dust/ice ratio of 0.4 to 2.6 and a porosity of 75 to 85%. The dust component may be comparable to that of carbonaceous chondrites.

Published
2015
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16. Insights gained from Data Measured by the CONSERT Instrument during Philae's Descent onto 67P/C-G's surface

Author

Dirk Plettemeier, Christoph Statz, Jens Abraham, Valérie Ciarletti, Ronny Hahnel, Sebastian Hegler, Alain Herique, Pierre Pasquero, Yves Rogez, Sonia Zine, Wlodek Kofman, Technische Universität Dresden = Dresden University of Technology (TU Dresden), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Dresden (TUD), IMPEC - LATMOS, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Cardon, Catherine, Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; The scientific objective of the Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) aboard ESA spacecraft Rosetta is to perform a dielectric characterization of comet 67P/Chuyurmov-Gerasimenko's nucleus. This is done by means of a bi-static sounding between the lander Philae launched onto the comet's surface and the orbiter Rosetta. For the sounding, the CONSERT unit aboard the lander will receive and process the radio signal emitted by the orbiter counterpart of the instrument. It will then retransmit a signal back to the orbiter to be received by CONSERT. This happens at the milliseconds time scale. During the descent of lander Philae onto the comet's surface, CONSERT was operated as a bi-static RADAR. A single measurement of the obtained data is composed of the dominant signal from the direct line-of-sight propagation path between lander and orbiter as well as paths from the lander's signal being reflected by the comet's surface. From peak power measurements of the dominant direct path during the descent, the knowledge of the orbiter and lander positions and simulations of CONSERT's orbiter and lander antenna characteristics as well as polarization properties, we were able to reconstruct the lander's attitude and estimate the spin rate of the lander along the descent trajectory. Additionally, certain operations and manoeuvres of orbiter and lander, e.g. the deployment of the lander legs and CONSERT antennas or the orbiter change of attitude in order to orient the science towards the assumed lander position, are also visible in the data. The information gained on the landers attitude is used in the reconstruction of the dielectric properties of 67P/C-G's surface and near subsurface (metric to decametric scale) and will hopefully prove helpful supporting the data interpretation of other instruments. In the CONSERT measurements, the comet's surface is visible during roughly the last third of the descent enabling a mean permittivity estimation of the surface and near subsurface covered by the instruments footprint along the descent path. The comparatively large timespan with surface signatures exhibits a spatial diversity necessary for the mapping of dominant signatures and the estimation of the dielectric properties of prominent features yielding a possible contrast and permittivity mapping of the comet's surface in the vicinity of the original landing site.

Published
2015

17. CONSERT suggests a change in local properties of 67P/Churyumov-Gerasimenko's nucleus at depth

Author

Anny Chantal Levasseur-Regourd, Dirk Plettemeier, Yves Rogez, Christoph Statz, Wlodek Kofman, Jérémie Lasue, Alain Herique, Valérie Ciarletti, IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Technische Universität Dresden (TUD), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Dresden = Dresden University of Technology (TU Dresden), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Permittivity, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, Dielectric, 01 natural sciences, Signal, law.invention, Optics, law, 0103 physical sciences, medicine, Comets, Radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, business.industry, Astronomy and Astrophysics, Space vehicles, Computational physics, medicine.anatomical_structure, Space and Planetary Science, Simulated data, Tomography, Numerical methods, business, Instruments, Nucleus
Abstract

International audience; After the successful landing of Philae on the nucleus of 67P/Churyumov-Gerasimenko, the Rosetta mission provided the first opportunity of performing measurements with the CONSERT tomographic radar in November 2014. CONSERT data were acquired during this first science sequence. They unambiguously showed that propagation through the smaller lobe of the nucleus was achieved. Aims. While the ultimate objective of the CONSERT radar is to perform the tomography of the nucleus, this paper focuses on the local characterization of the shallow subsurface in the area of Philae’s final landing site, specifically determining the possible presence of a permittivity gradient below the nucleus surface.Methods. A number of electromagnetic simulations were made with a ray-tracing code to parametrically study how the gradient of the dielectric constant in the near-subsurface affects the ability of CONSERT to receive signals.Results. At the 90 MHz frequency of CONSERT, the dielectric constant is a function of porosity, composition, and temperature. The dielectric constant values considered for the study are based on observations made by the other instruments of the Rosetta mission, which indicate a possible near-surface gradient in physical properties and on laboratory measurements made on analog samples. Conclusions. The obtained simulated data clearly show that if the dielectric constant were increasing with depth, it would have prevented the reception of signal at the CONSERT location during the first science sequence. We conclude from our simulations that the dielectric constant most probably decreases with depth.

Published
2015
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