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26 results on '"Dehant, Véronique"'

1. Mars rotation determination from a moving rover using Doppler tracking data: What could be done?

Author

UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sebastien, Rosenblatt, Pascal, Dehant, Véronique, Marty, Jean-Charles, Yseboodt, Marie, UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sebastien, Rosenblatt, Pascal, Dehant, Véronique, Marty, Jean-Charles, and Yseboodt, Marie

Abstract

This paper is a case study providing some insights on what improvement could be achieved on the Mars Orientation and rotation Parameters (MOP) determination using radio tracking data from a moving rover. Thanks to high-performance mobility systems onboard new generation of rovers like ExoMars 2020, the position of the rover can be precisely known with respect to its previous position. This characteristic, together with the long life of the rovers and their steerable high-gain-antenna communication system, is shown here to provide an unexpected opportunity to improve the MOP determination. This paper presents the results of numerical simulations involving radio-science experiments between the moving rover and the Earth ground stations as well as between the rover and an orbiting spacecraft. The benefits of combining both links (direct-to-Earth and rover-orbiter) for the MOP determination is also assessed. The impacts of the spacecraft position accuracy as well as the frequency band used to communicate with it are quantified. It is shown that, after one Martian year of operation, the polar motion could be determined with 5 milliarcsecond (mas) of precision (formal error) from the rover-orbiter Doppler link, while it cannot be determined with usual equatorial lander-to-Earth radio link. This would allow for the first time the direct detection of the Chandler wobble amplitude in the polar motion of Mars, which is an important quantity to constrain the planet interior and atmospheric models. Although the moving rover Doppler data alone barely improve the current precision on the other MOP (like the length-of-day and nutation), a combination of those together with historical and future lander data would definitely help to fill gaps in the MOP signal and to decorrelate between the estimated parameters, thereby reducing the uncertainties in their determination.

Published
2018

2. Signatures of the Martian rotation parameters in the Doppler and range observables

Author

UCL - SST/ELI/ELIC - Earth & Climate, Yseboodt, Marie, Dehant, Véronique, Péters, Marie-Julie, UCL - SST/ELI/ELIC - Earth & Climate, Yseboodt, Marie, Dehant, Véronique, and Péters, Marie-Julie

Abstract

The position of a Martian lander is affected by different aspects of Mars' rotational motions: the nutations, the precession, the length-of-day variations and the polar motion. These various motions have a different signature in a Doppler observable between the Earth and a lander on Mars’ surface. Knowing the correlations between these signatures and the moments when these signatures are not null during one day or on a longer timescale is important to identify strategies that maximize the geophysical return of observations with a geodesy experiment, in particular for the ones on-board the future NASA InSight or ESA-Roscosmos ExoMars2020 missions. We provide first-order formulations of the signature of the rotation parameters in the Doppler and range observables. These expressions are functions of the diurnal rotation of Mars, the lander position, the planet radius and the rotation parameter. Additionally, the nutation signature in the Doppler observable is proportional to the Earth declination with respect to Mars. For a lander on Mars close to the equator, the motions with the largest signature in the Doppler observable are due to the length-of-day variations, the precession rate and the rigid nutations. The polar motion and the liquid core signatures have a much smaller amplitude. For a lander closer to the pole, the polar motion signature is enhanced while the other signatures decrease. We also numerically evaluate the amplitudes of the rotation parameters signature in the Doppler observable for landers on other planets or moons.

Published
2017

3. Mars Express 10 years at Mars: Observations by the Mars Express Radio Science Experiment (MaRS)

Author

UCL - SST/ELI/ELIC - Earth & Climate, Pätzold, M., Häusler, B., Tyler, G.L., Andert, T., Asmar, S.W., Bird, M.K., Dehant, Véronique, UCL - SST/ELI/ELIC - Earth & Climate, Pätzold, M., Häusler, B., Tyler, G.L., Andert, T., Asmar, S.W., Bird, M.K., and Dehant, Véronique

Abstract

The Mars Express spacecraft is operating in Mars orbit since early 2004. The Mars Express Radio Science Experiment (MaRS) employs the spacecraft and ground station radio systems (i) to conduct radio occultations of the atmosphere and ionosphere to obtain vertical profiles of temperature, pressure, neutral number densities and electron density, (ii) to conduct bistatic radar experiments to obtain information on the dielectric and scattering properties of the surface, (iii) to investigate the structure and variation of the crust and lithosphere in selected target areas, (iv) to determine the mass, bulk and internal structure of the moon Phobos, and (v) to track the MEX radio signals during superior solar conjunction to study the morphology of coronal mass ejections (CMEs). Here we report observations, results and discoveries made in the Mars environment between 2004 and 2014 over almost an entire solar cycle. © 2016 Elsevier Ltd.

Published
2016

4. Mars Express investigations of Phobos and Deimos

Author

UCL - SST/ELI/ELIC - Earth & Climate, Witasse, O., Duxbury, T., Chicarro, A., Altobelli, N., Andert, T., Aronica, A., Barabash, S., Bertaux, J.-L., Bibring, J.-P., Cardesin-Moinelo, A., Cichetti, A., Companys, V., Dehant, Véronique, Denis, M., Formisano, V., Futaana, Y., Giuranna, M., Gondet, B., Heather, D., Hoffmann, H., Holmström, M., Manaud, N., Martin, P., Matz, K.-D., Montmessin, F., Morley, T., Mueller, M., Neukum, G., Oberst, J., Orosei, R., Pätzold, M., Picardi, G., Pischel, R., Plaut, J.J., Reberac, A., Pardo Voss, P., Roatsch, T., Rosenblatt, P., Remus, S., Schmedemann, N., Willner, K., Zegers, T., UCL - SST/ELI/ELIC - Earth & Climate, Witasse, O., Duxbury, T., Chicarro, A., Altobelli, N., Andert, T., Aronica, A., Barabash, S., Bertaux, J.-L., Bibring, J.-P., Cardesin-Moinelo, A., Cichetti, A., Companys, V., Dehant, Véronique, Denis, M., Formisano, V., Futaana, Y., Giuranna, M., Gondet, B., Heather, D., Hoffmann, H., Holmström, M., Manaud, N., Martin, P., Matz, K.-D., Montmessin, F., Morley, T., Mueller, M., Neukum, G., Oberst, J., Orosei, R., Pätzold, M., Picardi, G., Pischel, R., Plaut, J.J., Reberac, A., Pardo Voss, P., Roatsch, T., Rosenblatt, P., Remus, S., Schmedemann, N., Willner, K., and Zegers, T.

Published
2014

5. Phobos: Observed bulk properties

Author

UCL - SST/ELI/ELIC - Earth & Climate, Pätzold, Martin, Andert, Tom, Jacobson, Robert, Rosenblatt, Pascal, Dehant, Véronique, UCL - SST/ELI/ELIC - Earth & Climate, Pätzold, Martin, Andert, Tom, Jacobson, Robert, Rosenblatt, Pascal, and Dehant, Véronique

Published
2014

6. Phobos interior from librations determination using Doppler and star tracker measurements

Author

UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sebastien, Rosenblatt, Pascal, Rambaux, Nicolas, Castillo-Rogez, Julie C., Dehant, Véronique, Marty, Jean-Charles, UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sebastien, Rosenblatt, Pascal, Rambaux, Nicolas, Castillo-Rogez, Julie C., Dehant, Véronique, and Marty, Jean-Charles

Published
2013

8. Lander radio science experiment with a direct link between Mars and the Earth

Author

UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sébastien, Rosenblatt, Pascal, Rivoldini, Attilio, Dehant, Véronique, Marty, Jean-Charles, Karatekin, Ozgür, UCL - SST/ELI/ELIC - Earth & Climate, Le Maistre, Sébastien, Rosenblatt, Pascal, Rivoldini, Attilio, Dehant, Véronique, Marty, Jean-Charles, and Karatekin, Ozgür

Published
2012

9. From meteorites to evolution and habitability of planets

Author

UCL - SST/ELI/ELIC - Earth & Climate, Dehant, Véronique, Doris, Breuer, Philippe, Claeys, Vinciane, Debaille, Johan, De Keyser, Emmanuelle, Javaux, Steven, Goderis, Özgur, Karatekin, Tilman, Spohn, Ann Carine, Vandaele, Frank, Vanhaecke, Tim, Van Hoolst, Valérie, Wilquet, UCL - SST/ELI/ELIC - Earth & Climate, Dehant, Véronique, Doris, Breuer, Philippe, Claeys, Vinciane, Debaille, Johan, De Keyser, Emmanuelle, Javaux, Steven, Goderis, Özgur, Karatekin, Tilman, Spohn, Ann Carine, Vandaele, Frank, Vanhaecke, Tim, Van Hoolst, and Valérie, Wilquet

Published
2012

11. Penetrators for in situ subsurface investigations of Europa

Author

UCL - SST/ELI/ELIC - Earth & Climate, Gowen, R.A., Smith, A., Fortes, A.D., Barber, S., Brown, P., Church, P., Collinson, G., Coates, A.J., Collins, G., Crawford, I.A., Dehant, Véronique, Chela-Flores, J., Griffiths, A.D., Grindrod, P.M., Gurvits, L.I., Hagermann, A., Hussmann, H., Jaumann, R., Jones, A.P., Joy, K.H., Karatekin, O., Miljkovic, K., Palomba, E., Pike, W.T., Prieto-Ballesteros, O., Raulin, F., Sephton, M.A., Sheridan, S., Sims, M., Storrie-Lombardi, M.C., Ambrosi, R., Fielding, J., Fraser, G., Gao, Y., Jones, G.H., Kargl, G., Karl, W.J., Macagnano, A., Mukherjee, A., Muller, J.P., Phipps, A., Pullan, D., Richter, L., Sohl, F., Snape, J., Sykes, J., Wells, N., UCL - SST/ELI/ELIC - Earth & Climate, Gowen, R.A., Smith, A., Fortes, A.D., Barber, S., Brown, P., Church, P., Collinson, G., Coates, A.J., Collins, G., Crawford, I.A., Dehant, Véronique, Chela-Flores, J., Griffiths, A.D., Grindrod, P.M., Gurvits, L.I., Hagermann, A., Hussmann, H., Jaumann, R., Jones, A.P., Joy, K.H., Karatekin, O., Miljkovic, K., Palomba, E., Pike, W.T., Prieto-Ballesteros, O., Raulin, F., Sephton, M.A., Sheridan, S., Sims, M., Storrie-Lombardi, M.C., Ambrosi, R., Fielding, J., Fraser, G., Gao, Y., Jones, G.H., Kargl, G., Karl, W.J., Macagnano, A., Mukherjee, A., Muller, J.P., Phipps, A., Pullan, D., Richter, L., Sohl, F., Snape, J., Sykes, J., and Wells, N.

Published
2011

14. Lander radioscience for obtaining the rotation and orientation of Mars

Author

UCL - SST/ELI/ELIC - Earth & Climate, Dehant, Véronique, Folkner, William, Renotte, Etienne, Orban, Daniel, Asmar, Sami, Balmino, Georges, Barriot, Jean-Pierre, Benoist, Jeremy, Biancale, Richard, Biele, Jens, Budnik, Frank, Burger, Stefaan, de Viron, Olivier, Häusler, Bernd, Karatekin, Özgur, Le Maistre, Sébastien, Lognonné, Philippe, Menvielle, Michel, Mitrovic, Michel, Pätzold, Martin, Rivoldini, Attilio, Rosenblatt, Pascal, Schubert, Gerald, Spohn, Tilman, Tortora, Paolo, Van Hoolst, Tim, Witasse, Olivier, Yseboodt, Marie, UCL - SST/ELI/ELIC - Earth & Climate, Dehant, Véronique, Folkner, William, Renotte, Etienne, Orban, Daniel, Asmar, Sami, Balmino, Georges, Barriot, Jean-Pierre, Benoist, Jeremy, Biancale, Richard, Biele, Jens, Budnik, Frank, Burger, Stefaan, de Viron, Olivier, Häusler, Bernd, Karatekin, Özgur, Le Maistre, Sébastien, Lognonné, Philippe, Menvielle, Michel, Mitrovic, Michel, Pätzold, Martin, Rivoldini, Attilio, Rosenblatt, Pascal, Schubert, Gerald, Spohn, Tilman, Tortora, Paolo, Van Hoolst, Tim, Witasse, Olivier, and Yseboodt, Marie

Published
2009

16. Martian gravity field model and its time variations from MGS and Odyssey data

Author

UCL - SST/ELI/ELIC - Earth & Climate, Marty, J.C., Balmino, G., Duron, J., Rosenblatt, P., Le Maistre, S., Rivoldini, A., Dehant, Véronique, Van Hoolst, T., UCL - SST/ELI/ELIC - Earth & Climate, Marty, J.C., Balmino, G., Duron, J., Rosenblatt, P., Le Maistre, S., Rivoldini, A., Dehant, Véronique, and Van Hoolst, T.

Published
2009

18. The BepiColombo Laser Altimeter (BELA): Concept and baseline design

Author

UCL - SST/ELI/ELIC - Earth & Climate, Thomas, N., Spohn, T., Barriot, J.-P., Benz, W., Beutler, G., Christensen, U., Dehant, Véronique, Fallnich, C., Giardini, D., Groussin, O., Gunderson, K., Hauber, E., Hilchenbach, M., Iess, L., Lamy, P., Lara, L.-M., Lognonné, P., Lopez-Moreno, J.J., Michaelis, H., Oberst, J., Resendes, D., Reynaud, J.-L., Rodrigo, R., Sasaki, S., Seiferlin, K., Wieczorek, M., Whitby, J., UCL - SST/ELI/ELIC - Earth & Climate, Thomas, N., Spohn, T., Barriot, J.-P., Benz, W., Beutler, G., Christensen, U., Dehant, Véronique, Fallnich, C., Giardini, D., Groussin, O., Gunderson, K., Hauber, E., Hilchenbach, M., Iess, L., Lamy, P., Lara, L.-M., Lognonné, P., Lopez-Moreno, J.J., Michaelis, H., Oberst, J., Resendes, D., Reynaud, J.-L., Rodrigo, R., Sasaki, S., Seiferlin, K., Wieczorek, M., and Whitby, J.

Published
2007

20. Geophysical excitation of the Earth orientation parameters EOP and its contribution to GGOS

Author

UCL - SC/PHYS - Département de physique, Dehant, Véronique, Viron, Olivier de, Barriot, Jean-Pierre, UCL - SC/PHYS - Département de physique, Dehant, Véronique, Viron, Olivier de, and Barriot, Jean-Pierre

Abstract

We discuss how the geophysical fluids affect the Earth orientation parameters (EOP) and in particular polar motion and nutation. We show that the Earth orientation modeling is a perfect example of the integrated approach recommended by GGOS. GGOS considers the Earth system as a whole, including the solid Earth as well as the fluid components; geodesy observes and models the dynamics inside this system through the static and time-varying gravity field, the station displacements, and the Earth orientation parameters and the associated length-of-day variation, nutation and polar motion. Global-scale transfer in the Earth system and its geodetic consequences is proposed to be the central theme of GGOS. We show that the Earth orientation parameters perfectly fit this theme.

Published
2005

22. Earth rotation as an interdisciplinary topic shared by astronomers, geodesists and geophysicists

Author

UCL - SC/PHYS - Département de physique, Dehant, Véronique, de Viron, O., UCL - SC/PHYS - Département de physique, Dehant, Véronique, and de Viron, O.

Abstract

Earth rotation is characterized by its angular speed and by the position of the rotation axis both in space and in a frame tied to the Earth. The changes of the angular velocity induce changes in the length-of-day, and the variation of the position of the rotation axis is associated with polar motion (in the reference frame tied to the Earth) and with precession-nutation (in the space-fixed reference frame). These effects can be decomposed into components varying at different time scales. The study of their causes involves in different fields of physics, from astronomy for the rigid Earth nutation, through internal geophysics for the length-of-day variation at the decadal time scale, to external geophysics for seasonal polar motion. In this paper, we show how each discipline brings its own light into the observation, understanding and modeling of the Earth's rotation.

Published
2002

23. Steady-state convection in Mars’ mantle

Author

UCL - SST/ELI/ELIC - Earth & Climate, Defraigne, P., Dehant, Véronique, Van Hoolst, T., UCL - SST/ELI/ELIC - Earth & Climate, Defraigne, P., Dehant, Véronique, and Van Hoolst, T.

Published
2001

24. The NetLander very broad band seismometer

Author

UCL - SST/ELI/ELIC - Earth & Climate, Lognonné, P, Giardini, D, Banerdt, B, Gagnepain-Beyneix, J, Mocquet, A, Spohn, T, Karczewski, J.F, Schibler, P, Cacho, S, Pike, W.T, Cavoit, C, Desautez, A, Favède, M, Gabsi, T, Simoulin, L, Striebig, N, Campillo, M, Deschamp, A, Hinderer, J, Lévéque, J.J, Montagner, J.P, Rivéra, L, Benz, W, Breuer, D, Defraigne, P, Dehant, Véronique, Fujimura, A, Mizutani, H, Oberst, J, UCL - SST/ELI/ELIC - Earth & Climate, Lognonné, P, Giardini, D, Banerdt, B, Gagnepain-Beyneix, J, Mocquet, A, Spohn, T, Karczewski, J.F, Schibler, P, Cacho, S, Pike, W.T, Cavoit, C, Desautez, A, Favède, M, Gabsi, T, Simoulin, L, Striebig, N, Campillo, M, Deschamp, A, Hinderer, J, Lévéque, J.J, Montagner, J.P, Rivéra, L, Benz, W, Breuer, D, Defraigne, P, Dehant, Véronique, Fujimura, A, Mizutani, H, and Oberst, J

Published
2000

25. Chandler wobble and Free Core Nutation for Mars

Author

UCL - SST/ELI/ELIC - Earth & Climate, Van Hoolst, Tim, Dehant, Véronique, Defraigne, Pascale, UCL - SST/ELI/ELIC - Earth & Climate, Van Hoolst, Tim, Dehant, Véronique, and Defraigne, Pascale

Published
2000

26. Network science landers for Mars

Author

UCL - SST/ELI/ELIC - Earth & Climate, Harri, A.-M., Marsal, O., Lognonne, P., Leppelmeier, G.W., Spohn, T., Glassmeier, K.-H., Angrilli, F., Banerdt, W.B., Barriot, J.P., Bertaux, J.-L., Berthelier, J.J., Calcutt, S., Cerisier, J.C., Crisp, D., Dehant, Véronique, Giardini, D., Jaumann, R., Langevin, Y., Menvielle, M., Musmann, G., Pommereau, J.P., Di Pippo, S., Guerrier, D., Kumpulainen, K., Larsen, S., Mocquet, A., Polkko, J., Runavot, J., Schumacher, W., Siili, T., Simola, J., Tillman, J.E., UCL - SST/ELI/ELIC - Earth & Climate, Harri, A.-M., Marsal, O., Lognonne, P., Leppelmeier, G.W., Spohn, T., Glassmeier, K.-H., Angrilli, F., Banerdt, W.B., Barriot, J.P., Bertaux, J.-L., Berthelier, J.J., Calcutt, S., Cerisier, J.C., Crisp, D., Dehant, Véronique, Giardini, D., Jaumann, R., Langevin, Y., Menvielle, M., Musmann, G., Pommereau, J.P., Di Pippo, S., Guerrier, D., Kumpulainen, K., Larsen, S., Mocquet, A., Polkko, J., Runavot, J., Schumacher, W., Siili, T., Simola, J., and Tillman, J.E.

Published
1999

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