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  - Ahrens, Thomas J.
A1  - Altobelli, Nicolas
A1  - Auer, S.
A1  - Bradley, J. G.
A1  - Burton, M.
A1  - Dikarev, V. V.
A1  - Economou, T.
A1  - Fechtig, Hugo
A1  - Görlich, M.
A1  - Grande, M.
A1  - Graps, Amara
A1  - Grün, Eberhard
A1  - Havnes, Ove
A1  - Helfert, Stefan
A1  - Horanyi, Mihaly
A1  - Igenbergs, E.
A1  - Jessberger, Elmar K.
A1  - Johnson, T. V.
A1  - Kempf, Sascha
A1  - Krivov, Alexander v.
A1  - Krüger, Harald
A1  - Mocker-Ahlreep, Anna
A1  - Moragas-Klostermeyer, Georg
A1  - Lamy, Philippe
A1  - Landgraf, Markus
A1  - Linkert, Dietmar
A1  - Linkert, G.
A1  - Lura, F.
A1  - McDonnell, J. A. M.
A1  - Moehlmann, Dirk
A1  - Morfill, Gregory E.
A1  - Muller, M.
A1  - Roy, M.
A1  - Schafer, G.
A1  - Schlotzhauer, G.
A1  - Schwehm, Gerhard H.
A1  - Spahn, Frank
A1  - Stübig, M.
A1  - Svestka, Jiri
A1  - Tschernjawski, V
T1  - The Cassini Cosmic Dust Analyzer
N2  - The Cassini-Huygens Cosmic Dust Analyzer (CDA) is intended to provide direct observations of dust grains with masses between 10(-19) and 10(-9) kg in interplanetary space and in the jovian and saturnian systems, to investigate their physical, chemical and dynamical properties as functions of the distances to the Sun, to Jupiter and to Saturn and its satellites and rings, to study their interaction with the saturnian rings, satellites and magnetosphere. Chemical composition of interplanetary meteoroids will be compared with asteroidal and cometary dust, as well as with Saturn dust, ejecta from rings and satellites. Ring and satellites phenomena which might be effects of meteoroid impacts will be compared with the interplanetary dust environment. Electrical charges of particulate matter in the magnetosphere and its consequences will be studied, e.g. the effects of the ambient plasma and the magnetic held on the trajectories of dust particles as well as fragmentation of particles due to electrostatic disruption. The investigation will be performed with an instrument that measures the mass, composition, electric charge, speed, and flight direction of individual dust particles. It is a highly reliable and versatile instrument with a mass sensitivity 106 times higher than that of the Pioneer 10 and I I dust detectors which measured dust in the saturnian system. The Cosmic Dust Analyzer has significant inheritance from former space instrumentation developed for the VEGA, Giotto, Galileo, and Ulysses missions. It will reliably measure impacts from as low as I impact per month up to 104 impacts per second. The instrument weighs 17 kg and consumes 12 W, the integrated time-of-flight mass spectrometer has a mass resolution of up to 50. The nominal data transmission rate is 524 bits/s and varies between 50 and 4192 bps
Y1  - 2004
SN  - 0038-6308
ER  - 
TY  - GEN
A1  - Grün, Eberhard
A1  - de Pater, Imke
A1  - Showalter, Mark
A1  - Spahn, Frank
A1  - Srama, Ralf
T1  - Physics of dusty rings: History and perspective
BT  - Foreword
T2  - Planetary and space science
Y1  - 2006
U6  - https://doi.org/10.1016/j.pss.2006.05.005
SN  - 0032-0633
VL  - 54
IS  - 9-10
SP  - 837
EP  - 843
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Spahn, Frank
A1  - Schmidt, Jürgen
A1  - Albers, Nicole
A1  - Hörning, Marcel
A1  - Makuch, Martin
A1  - Seiß, Martin
A1  - Kempf, Sascha
A1  - Srama, Ralf
A1  - Dikarev, Valeri
A1  - Helfert, Stefan
A1  - Moragas-Klostermeyer, Georg
A1  - Krivov, Alexander V.
A1  - Sremcevic, Miodrag
A1  - Tuzzolino, Anthony J.
A1  - Economou, Thanasis
A1  - Grün, Eberhard
T1  - Cassini dust measurements at Enceladus and implications for the origin of the E ring
Y1  - 2006
UR  - http://www.sciencemag.org/content/311/5766/1416.full
U6  - https://doi.org/10.1126/science.1121375
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  - Postberg, Frank
A1  - Kempf, Sascha
A1  - Schmidt, Jürgen
A1  - Brilliantov, Nikolai V.
A1  - Beinsen, Alexander
A1  - Abel, Bernd
A1  - Buck, Udo
A1  - Srama, Ralf
T1  - Sodium salts in E-ring ice grains from an ocean below the surface of Enceladus
N2  - Saturn's moon Enceladus emits plumes of water vapour and ice particles from fractures near its south pole(1-5), suggesting the possibility of a subsurface ocean(5-7). These plume particles are the dominant source of Saturn's E ring(7,8). A previous in situ analysis(9) of these particles concluded that the minor organic or siliceous components, identified in many ice grains, could be evidence for interaction between Enceladus' rocky core and liquid water(9,10). It was not clear, however, whether the liquid is still present today or whether it has frozen. Here we report the identification of a population of E-ring grains that are rich in sodium salts (similar to 0.5- 2% by mass), which can arise only if the plumes originate from liquid water. The abundance of various salt components in these particles, as well as the inferred basic pH, exhibit a compelling similarity to the predicted composition of a subsurface Enceladus ocean in contact with its rock core(11). The plume vapour is expected to be free of atomic sodium. Thus, the absence of sodium from optical spectra(12) is in good agreement with our results. In the E ring the upper limit for spectroscopy(12) is insufficiently sensitive to detect the concentrations we found.
Y1  - 2009
UR  - http://www.nature.com/nature/
U6  - https://doi.org/10.1038/Nature08046
SN  - 0028-0836
ER  - 
TY  - JOUR
A1  - Cuzzi, Jeff N.
A1  - Burns, Joseph A.
A1  - Charnoz, Sébastien
A1  - Clark, Roger N.
A1  - Colwell, Josh E.
A1  - Dones, Luke
A1  - Esposito, Larry W.
A1  - Filacchione, Gianrico
A1  - French, Richard G.
A1  - Hedman, Matthew M.
A1  - Kempf, Sascha
A1  - Marouf, Essam A.
A1  - Murray, Carl D.
A1  - Nicholson, Phillip D.
A1  - Porco, Carolyn C.
A1  - Schmidt, Jürgen
A1  - Showalter, Mark R.
A1  - Spilker, Linda J.
A1  - Spitale, Joseph N.
A1  - Srama, Ralf
A1  - Sremcević, Miodrag
A1  - Tiscareno, Matthew Steven
A1  - Weiss, John
T1  - An evolving view of Saturn's dynamic rings
N2  - We review our understanding of Saturn's rings after nearly 6 years of observations by the Cassini spacecraft. Saturn's rings are composed mostly of water ice but also contain an undetermined reddish contaminant. The rings exhibit a range of structure across many spatial scales; some of this involves the interplay of the fluid nature and the self-gravity of innumerable orbiting centimeter- to meter-sized particles, and the effects of several peripheral and embedded moonlets, but much remains unexplained. A few aspects of ring structure change on time scales as short as days. It remains unclear whether the vigorous evolutionary processes to which the rings are subject imply a much younger age than that of the solar system. Processes on view at Saturn have parallels in circumstellar disks.
Y1  - 2010
UR  - http://www.sciencemag.org/
U6  - https://doi.org/10.1126/science.1179118
SN  - 0036-8075
ER  - 
TY  - JOUR
A1  - Postberg, Frank
A1  - Schmidt, J.
A1  - Hillier, J.
A1  - Kempf, Sascha
A1  - Srama, Ralf
T1  - A salt-water reservoir as the source of a compositionally stratified plume on Enceladus
JF  - Nature : the international weekly journal of science
N2  - The discovery of a plume of water vapour and ice particles emerging from warm fractures ('tiger stripes') in Saturn's small, icy moon Enceladus(1-6) raised the question of whether the plume emerges from a subsurface liquid source(6-8) or from the decomposition of ice(9-12). Previous compositional analyses of particles injected by the plume into Saturn's diffuse E ring have already indicated the presence of liquid water(8), but the mechanisms driving the plume emission are still debated(13). Here we report an analysis of the composition of freshly ejected particles close to the sources. Salt-rich ice particles are found to dominate the total mass flux of ejected solids (more than 99 per cent) but they are depleted in the population escaping into Saturn's E ring. Ice grains containing organic compounds are found to be more abundant in dense parts of the plume. Whereas previous Cassini observations were compatible with a variety of plume formation mechanisms, these data eliminate or severely constrain non-liquid models and strongly imply that a salt-water reservoir with a large evaporating surface(7,8) provides nearly all of the matter in the plume.
Y1  - 2011
U6  - https://doi.org/10.1038/nature10175
SN  - 0028-0836
VL  - 474
IS  - 7353
SP  - 620
EP  - 622
PB  - Nature Publ. Group
CY  - London
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  - Srama, Ralf
A1  - Krueger, H.
A1  - Yamaguchi, T.
A1  - Stephan, T.
A1  - Burchell, M.
A1  - Kearsley, A. T.
A1  - Sterken, V.
A1  - Postberg, F.
A1  - Kempf, S.
A1  - Grün, Eberhard
A1  - Altobelli, Nicolas
A1  - Ehrenfreund, P.
A1  - Dikarev, V.
A1  - Horanyi, M.
A1  - Sternovsky, Zoltan
A1  - Carpenter, J. D.
A1  - Westphal, A.
A1  - Gainsforth, Z.
A1  - Krabbe, A.
A1  - Agarwal, Jessica
A1  - Yano, H.
A1  - Blum, J.
A1  - Henkel, H.
A1  - Hillier, J.
A1  - Hoppe, P.
A1  - Trieloff, M.
A1  - Hsu, S.
A1  - Mocker, A.
A1  - Fiege, K.
A1  - Green, S. F.
A1  - Bischoff, A.
A1  - Esposito, F.
A1  - Laufer, R.
A1  - Hyde, T. W.
A1  - Herdrich, G.
A1  - Fasoulas, S.
A1  - Jaeckel, A.
A1  - Jones, G.
A1  - Jenniskens, P.
A1  - Khalisi, E.
A1  - Moragas-Klostermeyer, Georg
A1  - Spahn, Frank
A1  - Keller, H. U.
A1  - Frisch, P.
A1  - Levasseur-Regourd, A. C.
A1  - Pailer, N.
A1  - Altwegg, K.
A1  - Engrand, C.
A1  - Auer, S.
A1  - Silen, J.
A1  - Sasaki, S.
A1  - Kobayashi, M.
A1  - Schmidt, J.
A1  - Kissel, J.
A1  - Marty, B.
A1  - Michel, P.
A1  - Palumbo, P.
A1  - Vaisberg, O.
A1  - Baggaley, J.
A1  - Rotundi, A.
A1  - Roeser, H. P.
T1  - SARIM PLUS-sample return of comet 67P/CG and of interstellar matter
JF  - EXPERIMENTAL ASTRONOMY
N2  - The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.
KW  - Interstellar dust
KW  - Cometary dust
KW  - Churyumov Gerasimenko
KW  - Interplanetary dust
KW  - IMF
KW  - Cosmic vision
KW  - Sample return
KW  - Dust collector
KW  - Mass spectrometry
Y1  - 2012
U6  - https://doi.org/10.1007/s10686-011-9285-7
SN  - 0922-6435
SN  - 1572-9508
VL  - 33
IS  - 2-3
SP  - 723
EP  - 751
PB  - SPRINGER
CY  - DORDRECHT
ER  -