Federal Centre for Complexity and Exobiology

About COEX









Royal Observatory of Belgium (KSB-ORB)

Address: 3 Avenue Circulaire, B1180 Brussels, Belgium
Contact person: Dehant Véronique v.dehant@oma.be


The team is involved in a network mission to Mars; this mission has a key role in the international Mars exploration’s strategy, as defined by the IMEWG (International Mars Exploration Working Group). The idea is to send landers in order to probe the interior of the planet through seismic monitoring, magnetic sounding, and measurements of its rotational dynamics. At the beginning of the 21st century the goal was close to being realized with the NetLander mission, which was sponsored by a broad consortium of nations in Europe and America . Unfortunately, budget difficulties and programmatic conflicts at CNES and NASA resulted in its recent cancellation (2003). However the scientific priorities for understanding the origin, evolution, environment and habitat of Mars remain, and a geophysical network is clearly required to make the measurements necessary to address these questions. The team is working on theoretical studies related to the NetLander goals and is also working on the Mars Express data. Our current knowledge of the internal structure of the planet is mainly based on observations of its gravity field and its rotation, and on the chemical analysis of some meteorites found on Earth that originate from Mars. The team is expert in the field of modeling of the rotation (nutation and libration) of terrestrial planets (mainly Earth, Mars, Mercury), gravity field determination of these planets from spacecraft observations, and interpretation of these quantities in terms of interior of the planets.

Research Projects
  1. Planetary geodesy feasibility of geodesy experiment based on Doppler and ranging measurement of radio signals from either landers or spacecraft (implementation of GINS-DYNAMO software, impact of the geometry landers-orbiter, strategy for the orientation parameter determination, maneuver effects, convergence of the parameters, effect of the number of landers, effect of the noise level, effect of the altitude and eccentricity of the orbit, effect of the number of observations per week, impact of the timing error);
  2. Determination of the gravity field, its static value, its temporal changes;
  3. Determination of rotation and orientation parameter;
  4. Influence of interior of the planet on rotation, orientation parameters (e.g. effect of the inner core on nutation and polar motion);
  5. Interpretation of variation of rotation in terms of ice cap changes (CO2 sublimation/ condensation process) and in terms of dynamics in the atmosphere using General Circulation Model (GCM) for determining geodesy parameters of Mars;
  6. Effect of tides on spacecraft and landers;
  7. Excitation of normal modes;
  8. Internal structure of terrestrial planets;
  9. Evolution of terrestrial planets.

Other (Public outreach, conferences, equipments ...)

Films have been performed all in high resolution and low resolution (.avi or .mpg)

  • NEIGE_landing.avi: landing of the airbags on the Martian surface.
  • NEIGE_liaison_LO.avi: signal of the radio links between the lander and the orbiter and the orbiter and the Earth.
  • NEIGE_liaison_LO-OT.avi: Earth orientation in space, orbiter orientation with respect to the Earth, radio link between the Earth and the orbiter and between the orbiter and the landers.
  • NEIGE_ liaison_LO-OT_all.avi: Earth orientation in space, orbiter orientation with respect to the Earth, ….
  • NEIGE_Doppler.avi: Doppler effect on the radio signal.
  • Lod_Mars.avi: variations of the length-of-day (LOD) of Mars due to CO 2 cond./sublime. process
  • Nutation_Mars.avi: nutation of Mars in space.
  • Pm_Mars.avi: polar motion of Mars.
  • NEIGE_lod_pm_nut.avi: variations of the length-of-day (LOD) of Mars due to CO 2 condensation/sublimation process in the ice caps and atmosphere respectively; nutation in space; polar motion.
  • NEIGE_gr_liq.avi: nutations of Mars for a planet with a liquid core and a solid core.
  • NEIGE_oeufs_gr_liq.avi: comparison with the row and cocked eggs; nutations of Mars for a planet with a liquid core and a solid core.
  • NEIGE_iono.avi: effect of the ionosphere on the radio signal.
  • NEIGE.avi: the whole set of films.
  • Mars_express.avi: effect of the gravitational attraction of the masses inside Mars and of the ice caps on the orbit of the orbiter.

The team has presented about 120 communications at conferences or meetings these last four years.



Design by B-USOC


logo Belgian Federal Science Policy Office
logo Belgium.be