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Magnetic field investigation of the Venus plasma environment: Expected new results from Venus Express
Barabash, S.; Russell, C. T.; Lammer, H. +24 more
The Venus Express mission is scheduled for launch in 2005. Among many other instruments, it carries a magnetometer to investigate the Venus plasma environment. Although Venus has no intrinsic magnetic moment, magnetic field measurements are essential in studying the solar wind interaction with Venus. Our current understanding of the solar wind int…
Titan's methane cycle
Atreya, Sushil K.; Ferri, Francesca; Niemann, Hasso B. +5 more
Methane is key to sustaining Titan's thick nitrogen atmosphere. However, methane is destroyed and converted to heavier hydrocarbons irreversibly on a relatively short timescale of approximately 10-100 million years. Without the warming provided by CH 4-generated hydrocarbon hazes in the stratosphere and the pressure induced opacity in t…
Venus Express science planning
Barabash, S.; Pätzold, M.; Zhang, T. L. +20 more
Venus Express is the first European mission to the planet Venus. Its payload consists of seven instruments and will investigate the atmosphere, the plasma environment, and the surface of Venus from orbit. Science planning is a complex process that takes into account requests from all experiments and the operational constraints. The planning of the…
Loss of hydrogen and oxygen from the upper atmosphere of Venus
Barabash, S.; Gunell, H.; Lammer, H. +9 more
Atmospheric escape from the upper atmosphere of Venus is mainly influenced by the loss of hydrogen and oxygen caused by the interaction of solar radiation and particle flux with the unprotected planetary environment. Because one main aim of the ASPERA-4 particle/plasma and VEX-MAG magnetic field experiments on board of ESA's forthcoming Venus Expr…
Cassini observations of Saturn's inner plasmasphere: Saturn orbit insertion results
Coates, A. J.; Johnson, R. E.; Thomsen, M. +13 more
We present new and definitive results of Cassini plasma spectrometer (CAPS) data acquired during passage through Saturn's inner plasmasphere by the Cassini spacecraft during the approach phase of the Saturn orbit insertion period. This analysis extends the original analysis of Sittler et al. [2005. Preliminary results on Saturn's inner plasmaspher…
Cassini RPWS observations of dust in Saturn's E Ring
Gurnett, D. A.; Kurth, W. S.; Averkamp, T. F. +1 more
The Cassini radio and plasma wave science (RPWS) instrument is sensitive to few-micron dust grains impacting on the spacecraft at relative speeds of order 10 km/s. Through the first year or so of operations in orbit at Saturn, the RPWS has made a number of both inclined and equatorial crossings of the E ring, particularly near the orbit of Encelad…
Composition of Titan's surface from Cassini VIMS
Sotin, C.; Brown, R. H.; Buratti, B. J. +15 more
Titan's bulk density along with Solar System formation models indicates considerable water as well as silicates as its major constituents. This satellite's dense atmosphere of nitrogen with methane is unique. Deposits or even oceans of organic compounds have been suggested to exist on Titan's solid surface due to UV-induced photochemistry in the a…
Radio science investigations by VeRa onboard the Venus Express spacecraft
Pätzold, M.; Bird, M. K.; Imamura, T. +10 more
The Venus Express Radio Science Experiment (VeRa) uses radio signals at wavelengths of 3.6 and 13 cm ("X"- and "S"-band, respectively) to investigate the Venus surface, neutral atmosphere, ionosphere, and gravity field, as well as the interplanetary medium. An ultrastable oscillator (USO) provides a high quality onboard reference frequency source;…
Cassini/VIMS hyperspectral observations of the HUYGENS landing site on Titan
Le Mouélic, S.; Rodriguez, S.; Sotin, C. +8 more
Titan is one of the primary scientific objectives of the NASA-ESA-ASI Cassini-Huygens mission. Scattering by haze particles in Titan's atmosphere and numerous methane absorptions dramatically veil Titan's surface in the visible range, though it can be studied more easily in some narrow infrared windows. The Visual and Infrared Mapping Spectrometer…
The electrostatic potential of E ring particles
Beckmann, U.; Kempf, S.; Srama, R. +3 more
Saturn's E ring is remarkable not only for its huge size. Based on optical measurements the ring was surprisingly found to mainly consist of ice particles of uniform size (radii between 0.3 and 2 microns) [Nicholson et al., 1996. Observations of Saturn's ring-plane crossing in August and November. Science 272, 509-516], though the source of the ri…