Search Publications
Direct measurement of winds on Titan
Fast, Kelly E.; Hewagama, Tilak; Kostiuk, Theodor +4 more
We report the first direct measurement of wind velocity in the atmosphere of Titan, one of only two examples in our solar system of a slowly-rotating body with a dense atmosphere and a prime target of the Cassini mission. Zonal wind velocity was determined from Doppler shift of ethane lines emitted from Titan's stratosphere (∼0.1-7 mbar) measured …
Modelling of thunderclouds and lightning generation on Titan
Lammer, H.; Molina-Cuberos, G. J.; Tokano, T. +1 more
The likelihood of lightning generation in Titan's troposphere is investigated by theoretical consideration and a numerical one-dimensional time-dependent thundercloud model. The main cloud electrification hypotheses proposed for terrestrial thunderstorms are examined taking into account recent knowledge concerning Titan's atmospheric state, especi…
Possible contribution of different energy sources to the production of organics in Titan's atmosphere
Coll, P.; Raulin, F.; Navarro-González, R. +1 more
A quantitative comparison of the products arising from the irradiation of a Titan's simulated atmosphere is presented. The energy sources used represent some of the main events that occur in the satellite's atmosphere. All of the compounds identified are classified in the hydrocarbon and nitrile chemical families. Almost all of the detected compou…
Capability of the Cassini/Huygens PWA-HASI to measure electrical conductivity in Titan
Rodrigo, R.; López-Moreno, J. J.; Molina-Cuberos, G. J. +1 more
The penetration of the Huygens probe through the atmosphere of Titan in 2004 will provide a unique opportunity to measure the electrical properties of its lower atmosphere. Many studies have been carried out to predict the density of electrons and the distribution of the major positive ions, but there is no recent analysis concerning the electrica…
Propagation of electromagnetic waves in the lower ionosphere of Titan
Rodrigo, R.; López-Moreno, J. J.; Molina-Cuberos, G. J. +6 more
Towards the end of 2004 during the descent of the HUYGENS probe the Permittivity, Wave and Altimetry instrument (PWA) as part of the HASI experiment will investigate electrical properties and electric field fluctuations in the atmosphere of Titan below 170 km. We have modelled the propagation of low frequency electromagnetic waves in the lower ion…
Polar ionic conductivity profile in fair weather conditions. Terrestrial test of the Huygens/Hasi-PWA instrument aboard the Comas Sola balloon
Rodrigo, R.; López-Moreno, J. J.; Molina-Cuberos, G. J. +2 more
The permittivity wave and altimetry (PWA) instrument is a part of the CASSINI/HUYGENS HASI experiment and was designed to determine the electrical parameters of the atmosphere of Titan in 2004. In December 1995, a balloon campaign was conducted in León, Spain, to test the HASI onboard hardware and software using a HUYGENS probe mock-up in an elect…
Determination of physical properties of planetary sub-surface layers by artificial impacts and penetrometry
Kargl, G.; Ball, A. J.; Kömle, N. I.
In recent years the exploration of planetary bodies by surface probes has entered a new phase of interest. The mechanical properties of the near-surface layers of cometary and planetary bodies, including their strength, texture and layering, are important parameters needed both for a proper physical understanding of these bodies and for the design…
Private life of an integrating sphere: the radiant homogeneity of the Descent Imager -Spectral Radiometer calibration sphere
Rizk, Bashar
Perturbations to an integrating sphere's radiant uniformity by a protruding optical system are mapped. A sphere provides the Descent Imager-Spectral Radiometer sensor head (DISR SH), a practical platform for many of its subsystems' calibrations, but the resulting nonuniformity threatens the goal of accurate radiometry. An apparatus with a nearly i…