Search Publications
The water production rate of Rosetta target Comet 67P/Churyumov-Gerasimenko near perihelion in 1996, 2002 and 2009 from Lyman α observations with SWAN/SOHO
Schmidt, W.; Bertaux, J. -L.; Combi, M. R. +1 more
We report here the observations of the hydrogen cloud in Lyman alpha emission of Comet 67P/Churyumov-Gerasimenko at the last three passages through its perihelion, in 1996, 2002 and 2009. This comet became the target of ESA space mission Rosetta in 2003, and is therefore of particular interest. The data were collected with the SWAN instrument on b…
Phobos: Observed bulk properties
Pätzold, Martin; Dehant, Véronique; Rosenblatt, Pascal +2 more
This work is a review of the mass determinations of the Mars moon Phobos by spacecraft close flybys, by solving for the Martian gravity field and by the analysis of secular orbit perturbations. The absolute value and accuracy is sensitive on the knowledge and accuracy of the Phobos ephemeris, of the spacecraft orbit, other perturbing forces acting…
Processing OMEGA/Mars Express hyperspectral imagery from radiance-at-sensor to surface reflectance
Bakker, W. H.; van Ruitenbeek, F. J. A.; van der Werff, H. M. A. +4 more
OMEGA/Mars Express hyperspectral imagery is an excellent source of data for exploring the surface composition of the planet Mars. Compared to terrestrial hyperspectral imagery, the data are challenging to work with; scene-specific transmission models are lacking, spectral features are shallow making them difficult to detect, and field data for val…
Preservation of ancient ice at Pavonis and Arsia Mons: Tropical mountain glacier deposits on Mars
Head, James W.; Weiss, David K.
Large tropical mountain glacier (TMG) deposits on the northwest flanks of the Tharsis Montes and Olympus Mons volcanoes are interpreted to be the record of ancient climates characteristic of Mars several hundred million years ago when planetary spin-axis obliquity was ~45°. During this era, polar volatiles (predominantly H2O) were mobil…
Geological features and evolution history of Sinus Iridum, the Moon
Xiao, Long; Qiao, Le; Zhao, Jiannan +2 more
The Sinus Iridum region is one of the important candidate landing areas for the future Chinese lunar robotic and human missions. Considering its flat topography, abundant geomorphic features and complex evolutionary history, this region shows great significance to both lunar science and landing exploration, including powered descent, surface traff…
Mapping lunar mare basalt units in mare Imbrium as observed with the Moon Mineralogy Mapper (M³)
Hiesinger, H.; Besse, S.; Thiessen, F. +1 more
We examine compositional variations of volcanic units in the Imbrium basin using spectral observations from the Moon Mineralogy Mapper (M³) instrument on board the Chandrayaan-1 spacecraft. The spectral range of M³ reflectance measurements from 400 to 3000 nm is well-suited to study distinctive absorption bands near 1000 and 2000 nm resulting from…
Spacecraft exploration of Phobos and Deimos
Hoffmann, Harald; Duxbury, Thomas C.; Zakharov, Alexander V. +1 more
We review the previous exploration of Phobos and Deimos by spacecraft. The first close-up images of Phobos and Deimos were obtained by the Mariner 9 spacecraft in 1971, followed by much image data from the two Viking orbiters at the end of the 70s, which formed the basis for early Phobos and Deimos shape and dynamic models. The Soviet Phobos 2 spa…
The Phobos geodetic control point network and rotation model
Oberst, J.; Zubarev, A.; Nadezhdina, I. +2 more
A new global control point network was derived for Phobos, based on SRC (Mars Express), Phobos-2, and Viking Orbiter image data. We derive 3-D Cartesian coordinates for 813 control points as well as improved pointing data for 202 SRC and Viking images in the Phobos-fixed coordinate system. The point accuracies vary from 4.5 m on the Phobos nearsid…
Middle to Late Amazonian tropical mountain glaciers on Mars: The ages of the Tharsis Montes fan-shaped deposits
Head, James W.; Kadish, Seth J.; Fastook, James L. +1 more
Fan-shaped deposits (FSDs) extending to the northwest of the Tharsis Montes on Mars are the remnants of Amazonian-aged, cold-based, tropical mountain glaciers. We use high-resolution images to perform new impact crater size-frequency distribution (CSFD) analyses on these deposits in an effort to constrain the timing and duration of ice accumulatio…
Evolution of electron pitch angle distributions across Saturn's middle magnetospheric region from MIMI/LEMMS
Livi, S.; Krupp, N.; Roussos, E. +5 more
We provide a global view of ~20 to 800 keV electron pitch angle distributions (PADs) close to Saturn's current sheet using observations from the Cassini MIMI/LEMMS instrument. Previous work indicated that the nature of pitch angle distributions in Saturn's inner to middle magnetosphere changes near the radial distance of 10RS. This work…