Publications (2)3.61 Total impact
Article: The Grain Impact Analyser and Dust Accumulator (GIADA) Experiment for the Rosetta Mission: Design, Performances and First Results[show abstract] [hide abstract]
ABSTRACT: The Grain Impact Analyser and Dust Accumulator (GIADA) onboard the ROSETTA mission to comet 67P/Churyumov–Gerasimenko is devoted to study the cometary dust environment. Thanks to the rendezvous configuration of the mission, GIADA will be plunged in the dust environment of the coma and will be able to explore dust flux evolution and grain dynamic properties with position and time. This will represent a unique opportunity to perform measurements on key parameters that no ground-based observation or fly-by mission is able to obtain and that no tail or coma model elaborated so far has been able to properly simulate. The coma and nucleus properties shall be, then, clarified with consequent improvement of models describing inner and outer coma evolution, but also of models about nucleus emission during different phases of its evolution. GIADA shall be capable to measure mass/size of single particles larger than about 15 μm together with momentum in the range 6.5 × 10−10 ÷ 4.0 × 10−4 kg m s−1 for velocities up to about 300 m s−1. For micron/submicron particles the cumulative mass shall be detected with sensitivity 10−10 g. These performances are suitable to provide a statistically relevant set of data about dust physical and dynamic properties in the dust environment expected for the target comet 67P/Churyumov–Gerasimenko. Pre-flight measurements and post-launch checkouts demonstrate that GIADA is behaving as expected according to the design specifications.Space Science Reviews 01/2007; 128(1):803-821. · 3.61 Impact Factor
Article: Physical properties of the aerosol debris generated by the impact of fragment H of comet P/Shoemaker-Levy 9 on Jupiter[show abstract] [hide abstract]
ABSTRACT: The physical properties of the aerosol debris coming from the impact of fragment H of comet P/Shoemaker-Levy on Jupiter are analyzed. Based on a high spatial resolution image set obtained at the 4.2m William Herschel Telescope at La Palma (Spain), we derived detailed limb darkening curves at three wavelengths (3600, 8920 and 9480 Å), which we used to retrieve the aerosol physical properties and spatial distribution in the central core region of the impact site. We derived these properties combining the observations at two dates, that corresponding to the night of July 18th, 1994, just after the impact time, and that of July 21st, 1994. Radiative transfer models in combination with a Mie scattering program were used to retrieve the possible values of aerosol properties and spatial distribution compatible with these observations. The main results of the model computations are that the particles are rather dark, with imaginary refractive indexes varying between 0.02 at 3600 Å and 0.006 in the 9000 Å region, have a mean radius of about 0.15 µm, and are distributed between 1 and 450 mbar with a total column concentration of 8.2 × 109 cm−2, giving a total optical thickness of 3.6 at 9480 Å. A lower limit to the volume of the impact debris aerosol is estimated to be that corresponding to a sphere of about 230 m in diameter.Geophysical Research Letters - GEOPHYS RES LETT. 01/1995; 22(12):1609-1612.
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ABSTRACT: The ESA ROSETTA mission will perform a rendezvous with comet 67P/Churyumov-Gerasimenko and will follow and study it from about 3.25 AU to perihelion at 1.34 AU and, during the foreseen extended mission, up to 2 AU post-perihelion, in order to observe for the first time the onset of activity of a comet and to follow its evolution. The GIADA (Grain Impact Analyser and Dust Accumulator) instrument, on board the ROSETTA orbiter, is aimed to analyse physical and dynamical properties of individual particles ejected by the nucleus and to monitor the dust flux and spatial distribution as a function of time. To achieve these scientific goals, GIADA is composed of different modules: an optical detection system, to monitor the light scattered by single particles entering the instrument, an impact sensor, to detect the momentum carried by the particles, and five micro-balances, to measure the dust flux from different directions. In this work we will describe the technical characteristics and the scientific performances of the flight model of the instrument. The preliminary results of GIADA calibration demonstrate that the instrument is perfectly compatible with design specifications and is suitable to achieve unprecedented scientific results about cometary dust physics.Advances in Space Research.