A5065699969- Planetary Science and Exploration
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Space Exploration and Technology
- Space Science and Extraterrestrial Life
- Scientific Research and Discoveries
- Spacecraft Design and Technology
- Spacecraft Dynamics and Control
- Space Satellite Systems and Control
- Stellar, planetary, and galactic studies
- Ionosphere and magnetosphere dynamics
- Inertial Sensor and Navigation
- Solar and Space Plasma Dynamics
- GNSS positioning and interference
- Spacecraft and Cryogenic Technologies
- Climate Change Communication and Perception
- Astronomical Observations and Instrumentation
- Space exploration and regulation
- Historical Astronomy and Related Studies
- Historical Geography and Cartography
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- High-pressure geophysics and materials
- Experimental and Theoretical Physics Studies
Royal Observatory of Belgium
2016-2025
Centre National d'Études Spatiales
2019
Cornell University
2005-2006
Earth‐based radar observations of the spin state Mercury at 35 epochs between 2002 and 2012 reveal that its axis is tilted by (2.04 ± 0.08) arc min with respect to orbit normal. The direction tilt suggests in or near a Cassini state. Observed rotation rate variations clearly exhibit an 88‐day libration pattern which due solar gravitational torques acting on asymmetrically shaped planet. amplitude forced libration, (38.5 1.6) sec, corresponds longitudinal displacement ∼450 m equator....
Abstract For the first time for any planetary body other than Earth, free wobble of pole called Chandler has been detected Mars with a period 206.9 ± 0.5 days and amplitude 10 cm from radio tracking observations Odyssey, Reconnaissance Orbiter (MRO), Global Surveyor (MGS), in order decreasing sensitivity. The motion rotation location on surface Mars, or polar motion, is observed using two different approaches: (1) joint global estimates Mars' orientation its gravity field (2) series...
On the basis of gravity and radar observations with Cassini spacecraft, moment inertia Titan orientation Titan's rotation axis have been estimated in recent studies. According to observed orientation, is close state. However, obliquity inconsistent estimate for an entirely solid occupying We propose a new state model which we assume presence liquid water ocean beneath ice shell consider gravitational pressure torques arising between different layers satellite. With model, find closer...
Mercury's annual longitudinal libration (88 days) and its mean rotation rate have been  determined based on independent observations from the ground-based radar (Margot et al., 2012), camera and/or laser altimetry (Stark 2015; Bertone 2021), radio science (Mazarico 2014; Genova 2019; Konopliv 2020). Although consistent, precision of measurements precludes identification a large solid inner core (Van Hoolst 2012). At same time, measured rates are largely inconsistent....
Abstract The melt zone in the volcanically active satellite Io plays a key role diverse processes such as volcanism, heat transfer, tidal dissipation, and orbital evolution of Galilean satellites Laplace resonance. Information on distribution, degree partial melt, possible existence global magma ocean has been derived from Galileo magnetic induction measurements, volcanic eruption temperatures, Hubble Space Telescope auroral spot observations but is currently inconclusive. Here, we calculate...
Earth's precession and nutations are mainly generated by the luni‐solar tidal torque. Diurnal retrograde variations in atmospheric oceanic angular momenta an Earth‐fixed reference system induce some additional nutation motions. Observed derived from very long baseline interferometry (VLBI) data, assuming that direction of observed quasars fixed space. In this study, we consider effects two possible causes for explaining discrepancies between those modeled MHB2000 (model adopted International...
Using the angular momentum approach, effect of atmosphere on Earth's nutation is evaluated from five atmospheric circulation models. Five frequencies are considered: annual and semiannual prograde retrograde terannual prograde. The 18.6‐year also only model that gives a long enough homogeneous series. results obtained different models noninverted barometer ocean intercompared compared with residuals between observed computed nutations. evaluation shown to be above observation precision,...