TY  - JOUR
A1  - Kempf, Sascha
A1  - Srama, Ralf
A1  - Grün, Eberhard
A1  - Mocker, Anna
A1  - Postberg, Frank
A1  - Hillier, Jon K.
A1  - Horanyi, Mihaly
A1  - Sternovsky, Zoltan
A1  - Abel, Bernd
A1  - Beinsen, Alexander
A1  - Thissen, Roland
A1  - Schmidt, Jürgen
A1  - Spahn, Frank
A1  - Altobelli, Nicolas
T1  - Linear high resolution dust mass spectrometer for a mission to the Galilean satellites
JF  - Planetary and space science
N2  - The discovery of volcanic activity on Enceladus stands out amongst the long list of findings by the Cassini mission to Saturn. In particular the compositional analysis of Enceladus ice particles by Cassini's Cosmic Dust Analyser (CDA) (Srama et al., 2004) has proven to be a powerful technique for obtaining information about processes below the moon's ice crust. Small amounts of sodium salts embedded in the particles' ice matrices provide direct evidence for a subsurface liquid water reservoir, which is, or has been, in contact with the moon's rocky core (Postberg et al., 2009, 2011b).
 Jupiter's Galilean satellites Ganymede, Europa, and Callisto are also believed to have subsurface oceans and are therefore prime targets for future NASA and ESA outer Solar System missions. The Galilean moons are engulfed in tenuous dust clouds consisting of tiny pieces of the moons' surfaces (Kruger et al., 1999), released by hypervelocity impacts of micrometeoroids, which steadily bombard the surfaces of the moons. In situ chemical analysis of these grains by a high resolution dust spectrometer will provide spatially resolved mapping of the surface composition of Europa. Ganymede, and Callisto, meeting key scientific objectives of the planned missions. However, novel high-resolution reflectron-type dust mass spectrometers (Sternovsky et al., 2007; Srama et al., 2007) developed for dust astronomy missions (Gran et al., 2009) are probably not robust enough to be operated in the energetic radiation environment of the inner Jovian system. In contrast, CDA's linear spectrometer is much less affected by harsh radiation conditions because its ion detector is not directly facing out into space. The instrument has been continuously operated on Cassini for 11 years. In this paper we investigate the possibility of operating a CDA-like instrument as a high resolution impact mass spectrometer. We show that such an instrument is capable of reliably identifying traces of organic and inorganic materials in the ice matrix of ejecta expected to be generated from the surfaces of the Galilean moons. These measurements are complementary, and in some cases superior, compared to other traditional techniques such as infrared remote sensing or in situ ion or neutral mass spectrometers.
KW  - Europa
KW  - Ganymede
KW  - Callisto
KW  - Surface composition
KW  - Mass spectroscopy
KW  - Dust
Y1  - 2012
U6  - https://doi.org/10.1016/j.pss.2011.12.019
SN  - 0032-0633
VL  - 65
IS  - 1
SP  - 10
EP  - 20
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Postberg, Frank
A1  - Grün, Eberhard
A1  - Horanyi, Mihaly
A1  - Kempf, Sascha
A1  - Krueger, Harald
A1  - Schmidt, Jürgen
A1  - Spahn, Frank
A1  - Srama, Ralf
A1  - Sternovsky, Zoltan
A1  - Trieloff, Mario
T1  - Compositional mapping of planetary moons by mass spectrometry of dust ejecta
JF  - Planetary and space science
N2  - Classical methods to analyze the surface composition of atmosphereless planetary objects from an orbiter are IR and gamma ray spectroscopy and neutron backscatter measurements. The idea to analyze surface properties with an in-situ instrument has been proposed by Johnson et al. (1998). There, it was suggested to analyze Europa's thin atmosphere with an ion and neutral gas spectrometer. Since the atmospheric components are released by sputtering of the moon's surface, they provide a link to surface composition. Here we present an improved, complementary method to analyze rocky or icy dust particles as samples of planetary objects from which they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets. The planetary bodies are enshrouded in clouds of ballistic dust particles, which are characteristic samples of their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Recent instrumental developments and tests allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since the detection rates are of the order of thousand per orbit, a spatially resolved mapping of the surface composition can be achieved. Certain bodies (e.g., Europa) with particularly dense dust clouds, could provide impact statistics that allow for compositional mapping even on single flybys. Dust impact velocities are in general sufficiently high at orbiters about planetary objects with a radius > 1000 km and with only a thin or no atmosphere. In this work we focus on the scientific benefit of a dust spectrometer on a spacecraft orbiting Earth's Moon as well as Jupiter's Galilean satellites. This 'dust spectrometer' approach provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution.
KW  - Moon
KW  - Europa
KW  - Ganymede
KW  - Dust
KW  - Surface composition
KW  - Spectrometry
Y1  - 2011
U6  - https://doi.org/10.1016/j.pss.2011.05.001
SN  - 0032-0633
VL  - 59
IS  - 14
SP  - 1815
EP  - 1825
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Thiessenhusen, Kai-Uwe
A1  - Colwell, Josh E.
A1  - Srama, Ralf
A1  - Grün, Eberhard
A1  - Spahn, Frank
T1  - Dynamics of dust ejected from enceladus : application to the cassini dust detector
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Srama, Ralf
A1  - Kempf, S.
A1  - Moragas-Klostermeyer, Georg
A1  - Helfert, S.
A1  - Ahrens, T. J.
A1  - Altobelli, N.
A1  - Auer, S.
A1  - Beckmann, U.
A1  - Bradley, J. G.
A1  - Burton, M.
A1  - Dikarev, V. V.
A1  - Economou, T.
A1  - Fechtig, H.
A1  - Green, S. F.
A1  - Grande, M.
A1  - Havnes, O.
A1  - Hillierf, J.K.
A1  - Horanyii, M.
A1  - Igenbergsj, E.
A1  - Jessberger, E. K.
A1  - Johnson, T. V.
A1  - Krüger, H.
A1  - Matt, G.
A1  - McBride, N.
A1  - Mocker, A.
A1  - Lamy, P.
A1  - Linkert, D.
A1  - Linkert, G.
A1  - Lura, F.
A1  - McDonnell, J.A.M.
A1  - Möhlmann, D.
A1  - Morfill, G. E.
A1  - Postberg, F.
A1  - Roy, M.
A1  - Schwehm, G.H.
A1  - Spahn, Frank
A1  - Svestka, J.
A1  - Tschernjawski, V.
A1  - Tuzzolino, A. J.
A1  - Wäsch, R.
A1  - Grün, E.
T1  - In situ dust measurements in the inner Saturnian system
JF  - Planetary and space science
N2  - In July 2004 the Cassini–Huygens mission reached the Saturnian system and started its orbital tour. A total of 75 orbits will be carried out during the primary mission until August 2008. In these four years Cassini crosses the ring plane 150 times and spends approx. 400 h within Titan's orbit. The Cosmic Dust Analyser (CDA) onboard Cassini characterises the dust environment with its extended E ring and embedded moons. Here, we focus on the CDA results of the first year and we present the Dust Analyser (DA) data within Titan's orbit. This paper does investigate High Rate Detector data and dust composition measurements. The authors focus on the analysis of impact rates, which were strongly variable primarily due to changes of the spacecraft pointing. An overview is given about the ring plane crossings and the DA counter measurements. The DA dust impact rates are compared with the DA boresight configuration around all ring plane crossings between June 2004 and July 2005. Dust impacts were registered at altitudes as high as 100 000 km above the ring plane at distances from Saturn between 4 and 10 Saturn radii. In those regions the dust density of particles bigger than 0.5 can reach values of 0.001m-3.
KW  - Cassini
KW  - dust
KW  - CDA
KW  - E-ring
KW  - water ice
Y1  - 2006
U6  - https://doi.org/10.1016/j.pss.2006.05.021
SN  - 0032-0633
VL  - 54
IS  - 9-10
SP  - 967
EP  - 987
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Arridge, Christopher S.
A1  - Achilleos, N.
A1  - Agarwal, Jessica
A1  - Agnor, C. B.
A1  - Ambrosi, R.
A1  - Andre, N.
A1  - Badman, S. V.
A1  - Baines, K.
A1  - Banfield, D.
A1  - Barthelemy, M.
A1  - Bisi, M. M.
A1  - Blum, J.
A1  - Bocanegra-Bahamon, T.
A1  - Bonfond, B.
A1  - Bracken, C.
A1  - Brandt, P.
A1  - Briand, C.
A1  - Briois, C.
A1  - Brooks, S.
A1  - Castillo-Rogez, J.
A1  - Cavalie, T.
A1  - Christophe, B.
A1  - Coates, Andrew J.
A1  - Collinson, G.
A1  - Cooper, John F.
A1  - Costa-Sitja, M.
A1  - Courtin, R.
A1  - Daglis, I. A.
A1  - De Pater, Imke
A1  - Desai, M.
A1  - Dirkx, D.
A1  - Dougherty, M. K.
A1  - Ebert, R. W.
A1  - Filacchione, Gianrico
A1  - Fletcher, Leigh N.
A1  - Fortney, J.
A1  - Gerth, I.
A1  - Grassi, D.
A1  - Grodent, D.
A1  - Grün, Eberhard
A1  - Gustin, J.
A1  - Hedman, M.
A1  - Helled, R.
A1  - Henri, P.
A1  - Hess, Sebastien
A1  - Hillier, J. K.
A1  - Hofstadter, M. H.
A1  - Holme, R.
A1  - Horanyi, M.
A1  - Hospodarsky, George B.
A1  - Hsu, S.
A1  - Irwin, P.
A1  - Jackman, C. M.
A1  - Karatekin, O.
A1  - Kempf, Sascha
A1  - Khalisi, E.
A1  - Konstantinidis, K.
A1  - Kruger, H.
A1  - Kurth, William S.
A1  - Labrianidis, C.
A1  - Lainey, V.
A1  - Lamy, L. L.
A1  - Laneuville, Matthieu
A1  - Lucchesi, D.
A1  - Luntzer, A.
A1  - MacArthur, J.
A1  - Maier, A.
A1  - Masters, A.
A1  - McKenna-Lawlor, S.
A1  - Melin, H.
A1  - Milillo, A.
A1  - Moragas-Klostermeyer, Georg
A1  - Morschhauser, Achim
A1  - Moses, J. I.
A1  - Mousis, O.
A1  - Nettelmann, N.
A1  - Neubauer, F. M.
A1  - Nordheim, T.
A1  - Noyelles, B.
A1  - Orton, G. S.
A1  - Owens, Mathew
A1  - Peron, R.
A1  - Plainaki, C.
A1  - Postberg, F.
A1  - Rambaux, N.
A1  - Retherford, K.
A1  - Reynaud, Serge
A1  - Roussos, Elias
A1  - Russell, C. T.
A1  - Rymer, Am.
A1  - Sallantin, R.
A1  - Sanchez-Lavega, A.
A1  - Santolik, O.
A1  - Saur, J.
A1  - Sayanagi, Km.
A1  - Schenk, P.
A1  - Schubert, J.
A1  - Sergis, N.
A1  - Sittler, E. C.
A1  - Smith, A.
A1  - Spahn, Frank
A1  - Srama, Ralf
A1  - Stallard, T.
A1  - Sterken, V.
A1  - Sternovsky, Zoltan
A1  - Tiscareno, M.
A1  - Tobie, G.
A1  - Tosi, F.
A1  - Trieloff, M.
A1  - Turrini, D.
A1  - Turtle, E. P.
A1  - Vinatier, S.
A1  - Wilson, R.
A1  - Zarkat, P.
T1  - The science case for an orbital mission to Uranus: Exploring the origins and evolution of ice giant planets
JF  - Planetary and space science
N2  - Giant planets helped to shape the conditions we see in the Solar System today and they account for more than 99% of the mass of the Sun's planetary system. They can be subdivided into the Ice Giants (Uranus and Neptune) and the Gas Giants (Jupiter and Saturn), which differ from each other in a number of fundamental ways. Uranus, in particular is the most challenging to our understanding of planetary formation and evolution, with its large obliquity, low self-luminosity, highly asymmetrical internal field, and puzzling internal structure. Uranus also has a rich planetary system consisting of a system of inner natural satellites and complex ring system, five major natural icy satellites, a system of irregular moons with varied dynamical histories, and a highly asymmetrical magnetosphere. Voyager 2 is the only spacecraft to have explored Uranus, with a flyby in 1986, and no mission is currently planned to this enigmatic system. However, a mission to the uranian system would open a new window on the origin and evolution of the Solar System and would provide crucial information on a wide variety of physicochemical processes in our Solar System. These have clear implications for understanding exoplanetary systems. In this paper we describe the science case for an orbital mission to Uranus with an atmospheric entry probe to sample the composition and atmospheric physics in Uranus' atmosphere. The characteristics of such an orbiter and a strawman scientific payload are described and we discuss the technical challenges for such a mission. This paper is based on a white paper submitted to the European Space Agency's call for science themes for its large-class mission programme in 2013.
KW  - Uranus
KW  - Magnetosphere
KW  - Atmosphere
KW  - Natural satellites
KW  - Rings
KW  - Planetary interior
Y1  - 2014
U6  - https://doi.org/10.1016/j.pss.2014.08.009
SN  - 0032-0633
VL  - 104
SP  - 122
EP  - 140
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Buratti, Bonnie J.
A1  - Thomas, P. C.
A1  - Roussos, Elias
A1  - Howett, Carly
A1  - Seiss, Martin
A1  - Hendrix, A. R.
A1  - Helfenstein, Paul
A1  - Brown, R. H.
A1  - Clark, R. N.
A1  - Denk, Tilmann
A1  - Filacchione, Gianrico
A1  - Hoffmann, Holger
A1  - Jones, Geraint H.
A1  - Khawaja, N.
A1  - Kollmann, Peter
A1  - Krupp, Norbert
A1  - Lunine, Jonathan
A1  - Momary, T. W.
A1  - Paranicas, Christopher
A1  - Postberg, Frank
A1  - Sachse, Manuel
A1  - Spahn, Frank
A1  - Spencer, John
A1  - Srama, Ralf
A1  - Albin, T.
A1  - Baines, K. H.
A1  - Ciarniello, Mauro
A1  - Economou, Thanasis
A1  - Hsu, Hsiang-Wen
A1  - Kempf, Sascha
A1  - Krimigis, Stamatios M.
A1  - Mitchell, Donald
A1  - Moragas-Klostermeyer, Georg
A1  - Nicholson, Philip D.
A1  - Porco, C. C.
A1  - Rosenberg, Heike
A1  - Simolka, Jonas
A1  - Soderblom, Laurence A.
T1  - Close Cassini flybys of Saturn’s ring moons Pan, Daphnis, Atlas, Pandora, and Epimetheus
JF  - Science
N2  - Saturn’s main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons’ morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons’ surfaces are determined by two competing processes: contamination by a red material formed in Saturn’s main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.
Y1  - 2019
U6  - https://doi.org/10.1126/science.aat2349
SN  - 0036-8075
SN  - 1095-9203
VL  - 364
IS  - 6445
SP  - 1053
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  -