@article{KempfSramaGruenetal.2012, author = {Kempf, Sascha and Srama, Ralf and Gr{\"u}n, Eberhard and Mocker, Anna and Postberg, Frank and Hillier, Jon K. and Horanyi, Mihaly and Sternovsky, Zoltan and Abel, Bernd and Beinsen, Alexander and Thissen, Roland and Schmidt, J{\"u}rgen and Spahn, Frank and Altobelli, Nicolas}, title = {Linear high resolution dust mass spectrometer for a mission to the Galilean satellites}, series = {Planetary and space science}, volume = {65}, journal = {Planetary and space science}, number = {1}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2011.12.019}, pages = {10 -- 20}, year = {2012}, abstract = {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.}, language = {en} } @article{PostbergGruenHoranyietal.2011, author = {Postberg, Frank and Gr{\"u}n, Eberhard and Horanyi, Mihaly and Kempf, Sascha and Krueger, Harald and Schmidt, J{\"u}rgen and Spahn, Frank and Srama, Ralf and Sternovsky, Zoltan and Trieloff, Mario}, title = {Compositional mapping of planetary moons by mass spectrometry of dust ejecta}, series = {Planetary and space science}, volume = {59}, journal = {Planetary and space science}, number = {14}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2011.05.001}, pages = {1815 -- 1825}, year = {2011}, abstract = {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.}, language = {en} } @misc{SzalayPoppeAgarwaletal.2018, author = {Szalay, J. R. and Poppe, A. R. and Agarwal, J. and Britt, D. and Belskaya, I. and Horanyi, M. and Nakamura, T. and Sachse, M. and Spahn, Frank}, title = {Dust Phenomena Relating to Airless Bodies}, series = {Space science reviews}, volume = {214}, journal = {Space science reviews}, number = {5}, publisher = {Springer}, address = {Dordrecht}, issn = {0038-6308}, doi = {10.1007/s11214-018-0527-0}, pages = {47}, year = {2018}, abstract = {Airless bodies are directly exposed to ambient plasma and meteoroid fluxes, making them characteristically different from bodies whose dense atmospheres protect their surfaces from such fluxes. Direct exposure to plasma and meteoroids has important consequences for the formation and evolution of planetary surfaces, including altering chemical makeup and optical properties, generating neutral gas and/or dust exospheres, and leading to the generation of circumplanetary and interplanetary dust grain populations. In the past two decades, there have been many advancements in our understanding of airless bodies and their interaction with various dust populations. In this paper, we describe relevant dust phenomena on the surface and in the vicinity of airless bodies over a broad range of scale sizes from to , with a focus on recent developments in this field.}, language = {en} }