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The Stickney Crater ejecta secondary impact crater spike on Phobos: Implications for the age of Stickney and the surface of Phobos

Head, James W.; Ramsley, Kenneth R.

A global and uniformly distributed spike of secondary impact craters on Phobos with diameters (D) <0.6 km and a portion of craters up to D 2 km were produced by Stickney Crater ejecta, including secondary craters within the surface area of Stickney Crater. The global exposure of Phobos to Stickney secondary impacts was facilitated by the desync…

Martian ionosphere observed by Mars Express. 2. Influence of solar irradiance on upper ionosphere and escape fluxes

Barabash, S.; Pätzold, M.; Dubinin, E. +4 more

We present multi-instrument observations of the effects of solar irradiance on the upper Martian ionosphere and escape fluxes based on Mars Express measurements obtained over almost 12 years. It is shown that the variations in the upper ionosphere caused by solar irradiance lead to significant changes in the trans-terminator fluxes of low-energy i…

Response of the Martian ionosphere to solar activity including SEPs and ICMEs in a two-week period starting on 25 February 2015

Gurnett, D. A.; Lundin, R.; Winningham, J. D. +15 more

In a two-week period between February and March of 2015, a series of interplanetary coronal mass ejections (ICMEs) and solar energetic particle (SEP) events encountered Mars. The interactions were observed by several spacecraft, including Mars Express (MEX), Mars Atmosphere and Volatile Evolution Mission (MAVEN), and Mars Odyssey (MO). The ICME di…

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

Yseboodt, Marie; Dehant, Véronique; Péters, Marie-Julie

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 …

On the estimation of the current density in space plasmas: Multi- versus single-point techniques

Sorriso-Valvo, Luca; Perri, Silvia; Malara, Francesco +2 more

Thanks to multi-spacecraft mission, it has recently been possible to directly estimate the current density in space plasmas, by using magnetic field time series from four satellites flying in a quasi perfect tetrahedron configuration. The technique developed, commonly called ;curlometer; permits a good estimation of the current density when the ma…

Geologic analysis of the Rosetta NavCam, Osiris and ROLIS images of the comet 67P/Churyumov-Gerasimenko nucleus

Keller, H. U.; Mottola, S.; Hviid, S. F. +5 more

This paper is based on geologic analysis of the surface morphology of nucleus of the Jupiter family comet 67P. This comet was visited by the ESA mission Rosetta, which escorted the comet since May 2014 till the end of September 2016 and studied it by 11 instruments of the mission orbiter and 10 instruments of the lander. The nucleus is 4 km in dia…

UV production of methane from surface and sedimenting IDPs on Mars in light of REMS data and with insights for TGO

Moores, John E.; Smith, Christina L.; Schuerger, Andrew C.

This paper refines model predictions for the production of methane from UV-irradiated interplanetary dust particles (IDPs) now that the Rover Environmental Monitoring Station (REMS) instrument onboard the Mars Science Laboratory (MSL) Rover has made the first measurements of the UV environment on the surface of Mars, at Gale Crater. Once these mea…

Distance determination method of dust particles using Rosetta OSIRIS NAC and WAC data

Jorda, L.; Lara, L. M.; Bertaux, J. -L. +42 more

The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dus…

Pinnacles on the 67P comet nucleus: Evidence for large scale erosion and hierarchical agglomeration of the nucleus

Keller, H. U.; Mall, U.; Basilevsky, A. T. +3 more

Grid-mapping Hellas Planitia, Mars - Insights into distribution, evolution and geomorphology of (Peri)-glacial, fluvial and lacustrine landforms in Mars' deepest basin

Jaumann, R.; Hauber, E.; Voelker, M. +1 more

Traditional maps of Hellas Planitia, the most prominent impact basin on Mars, have focused on the delineation of continuous surface units. We applied the newly developed grid-mapping method in order to quantitatively analyze the distribution and geostatistics of selected (peri)-glacial, fluvial, and lacustrine landforms. The study area was subdivi…