Search Publications
High-resolution Enceladus atlas derived from Cassini-ISS images
Scholten, F.; Matz, K. -D.; Neukum, G. +8 more
The Cassini Imaging Science Subsystem (ISS) acquired 377 high-resolution images (<1 km/pixel) during three close flybys of Enceladus in 2005 [Porco, C.C., et al., 2006. Cassini observes the active south pole of Enceladus. Science 311, 1393-1401.]. We combined these images with lower resolution Cassini images and four others taken by Voyager cam…
Albedo models for the residual south polar cap on Mars: Implications for the stability of the cap under near-perihelion global dust storm conditions
Bjorkman, Jon E.; James, Philip B.; Bonev, Boncho P. +2 more
It is uncertain whether the residual (perennial) south polar cap on Mars is a transitory or a permanent feature in the current Martian climate. While there is no firm evidence for complete disappearance of the cap in the past, clearly observable changes have been documented. Observations suggest that the perennial cap lost more CO 2 mat…
High-resolution Dione atlas derived from Cassini-ISS images
Scholten, F.; Matz, K. -D.; Neukum, G. +7 more
The Cassini imaging science subsystem (ISS) acquired 449 high-resolution images (<800 m/pixel) during one close flyby of Dione in 2005 and three non-targeted flybys in 2004, 2006, and 2007. We combined these images with lower-resolution Cassini images and one other taken by Voyager cameras to produce a high-resolution semi-controlled mosaic of …
Huygens probe entry trajectory and attitude estimated simultaneously with Titan atmospheric structure by Kalman filtering
Colombatti, Giacomo; Aboudan, Alessio; Ferri, Francesca +1 more
Space probes entering planetary atmospheres are used for in situ study of their physical structures. During the entry phase aerodynamic forces exerted on the probe depend on atmospheric density. As a consequence accelerations measured by on-board sensors can be used to derive probe trajectory as well as atmospheric density, pressure and temperatur…
On the properties of O + and O 2+ ions in a hybrid model and in Mars Express IMA/ASPERA-3 data: A case study
Kallio, E.; Fedorov, A.; Budnik, E. +3 more
We have performed a numerical simulation to analyze the energy spectra of escaping planetary O + and O 2+ ions at Mars. The simulated time-energy spectrograms were generated along orbit no. 555 (June 27, 2004) of Mars Express when its Ion Mass Analyzer (IMA)/ASPERA-3 ion instrument detected escaping planetary ions.…
First observation of energetic neutral atoms in the Venus environment
Coates, A. J.; Kallio, E.; Fedorov, A. +48 more
The ASPERA-4 instrument on board the Venus Express spacecraft offers for the first time the possibility to directly measure the emission of energetic neutral atoms (ENAs) in the vicinity of Venus. When the spacecraft is inside the Venus shadow a distinct signal of hydrogen ENAs usually is detected. It is observed as a narrow tailward stream, comin…
Optical properties of aerosols in Titan's atmosphere
Keller, H. U.; Rodin, A. V.; Skorov, Yu. V.
In the frame of fractal modeling of tholin aggregates we made a systematic analysis of their optical properties. Ballistic particle-cluster aggregation (BPCA) and diffusion-limited aggregation (DLA) of spherical primary particles (monomers) identical in material composition were considered. Aggregates composed of identical particles (monodisperse …
ENA detection in the dayside of Mars: ASPERA-3 NPD statistical study
Coates, A. J.; Kallio, E.; Fedorov, A. +32 more
The Analyzer of Space Plasma and EneRgetic Atoms (ASPERA-3) on board Mars Express is designed to study the interaction between the solar wind and the atmosphere of Mars and to characterize the plasma and neutral gas environment in near-Mars space. Neutral Particle Detectors (NPD-1 and 2), which form part of the ASPERA-3 instrument suite, are Energ…
Influence of IMF draping direction and crustal magnetic field location on Martian ion beams
Barabash, S.; Lundin, R.; Grigoriev, A. +4 more
Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite onboard Mars Express and data from the Magnetometer/Electron Reflectometer (MAG/ER) on Mars Global Surveyor have been analyzed to determine whether ion beam events (IBEs) are correlated with the direction of the draped interplanetary magnetic field (IMF) or the proximity…
A coordinated campaign of Venus ground-based observations and Venus Express measurements
Lellouch, Emmanuel; Witasse, Olivier