156 research outputs found
Reply to Lanari, R., et al. comment on “pre-collapse space geodetic observations of critical infrastructure: The morandi bridge, Genoa, Italy” by Milillo et al. (2019)
No full textWe would like to thank our colleagues for their comment, as we believe that this discussion further highlights the importance of innovative research in the emerging field of InSAR applications to civil engineering structures. We discuss the statement from Lanari et al. (2020): “Our analysis shows that, although both the SBAS and the TomoSAR analyses allow achieving denser coherent pixel maps relevant to the Morandi bridge, nothing of the pre-collapse large displacements reported in Milillo et al. (2019) appears in our results”. In this reply we argue that (1) they cannot detect the pre-collapse movements because they use standard approaches and (2) the signals of interest become observable by changing the point of view.Geo-engineerin
Estimating atmospheric density profiles using orbit determination with a focus on JUICE and Cassini
No full textOrbit determination allows us to determine a spacecraft’s position, velocity, and dynamical model parameters that directly affect a spacecraft’s trajectory, such as gravity field coefficients, which relate to the interior structure of a planetary body, and tidal forces. In addition, when a spacecraft experiences substantial drag in the presence of an exosphere/atmosphere, the density profile may be estimated. This work presents an analysis of two cases where atmospheric drag has effects on the orbit and gravity measurements in planetary missions: Cassini, the mission to Saturn’s system which ended with a plunge into the planet in 2017, and JUICE, the future mission to Jupiter’s icy moons which will include an insertion into a circular, polar orbit around Ganymede.
For Saturn, we have estimated a vertical atmospheric density profile which we have compared with in-situ measurements taken by Cassini’s INMS (Ion and Neutral Mass Spectrometer). For Ganymede, we find that the exosphere may be dense enough to affect JUICE’s trajectory around the moon
ASI - SERENA RAV 04 - Activity report
No full textReport di attività periodo
Giugno 2019 –Ottobre 2020
Per l’Accordo ASI-INAF 2018-8-HH.0
Partecipazione scientifica alla missione BEPICOLOMBO SERENA Fase E
ASI - SERENA RAV 01 - Activity report
No full textReport di attività periodo
Maggio 2018 –Settembre 2018
Per l’Accordo ASI-INAF 2018-8-HH.0
Partecipazione scientifica alla missione BEPICOLOMBO SERENA Fase E
Jupiter’s magnetosphere: plasma sources and transport
No full textJupiter's plasma environment is one of the most interesting plasma laboratories in our solar System. The giant magnetosphere of Jupiter is fuelled primarily by the ionization of volcanic gases from volcanic moon Io, with additional minor sources from the other, icy, Galilean moons. Embedded in the inner Jovian magnetosphere, the icy moons experience a strong interaction with their surrounding plasma. There is likely a source of light ions from the atmosphere and ionosphere of Jupiter but it has neither been accurately measured nor modelled. Two major mysteries at Jupiter are the mechanism that heats the plasma as it moves outwards from the Io plasma torus, and the mechanism by which plasma is lost from the system.</p
Editorial to “Surface-Bounded Exospheres and Interactions in the Inner Solar System”
No full textStudying the evolution of the surfaces and atmospheres of planetary bodies in the solar sys-
tem is fundamental to our understanding of the present state of the solar system. Exospheres
are the interfaces between the planetary body and the open space, so that, studying the ex-
ospheric filling and loss processes is the way to expand knowledge of the body’s evolution.
This endeavour entails finding variation of the rates of the ongoing processes as a function
of the space environment, or, in other words, how the planetary space weather affects these
bodies. Aside from occasional catastrophic events, such as volcanic eruptions and geysers
in a few bodies or occasional impacts of comets and asteroids, surface and atmospheric
changes are caused predominantly by the continuous bombardment of the bodies by pho-
tons, energetic ions, and micrometeoroids.
While the exospheres are present around any kind of planetary body, they are quite dif-
ferent if we consider the bodies with an atmosphere and those without a collisional gas en-
velope. In fact, in the former case the exosphere is the upper part of the gas envelope where
collisions become less and less frequent with altitude, so that, the boundary, the exobase, is a
thick shell only conventionally defined as the surface where Knudsen number, Kn (the ratio
of the mean free path over the atmospheric scale height), is equal to unity. On the contrary,
in the latter case the exosphere is directly connected to the surface, thus, it is called surface-
bounded exosphere, since the surface release processes are also the exospheric filling ones
and atoms and molecules collide with the surface far more frequently than collisions with
each other. In this case, the exobase is considered the surface itself, but it has quite different
characteristics from the exosphere – atmosphere boundary
ELENA HK pipeline verification SERENA
No full textAfter the activity of SERENA Rehearsal on March 2020 with ESAC team, has been compared output of ELENA pipeline both from ESA Planetary Science Archive (PSA) Colombo-SERENA Local Archive and from IAPS Visualization Tool
The H2O and O2 exospheres of Ganymede: The result of a complex interaction between the jovian magnetospheric ions and the icy moon
No full textAcknowledgments The authors are grateful to both referees for their in depth review of the manuscript that improved substantially the current analysis. This paper is financially supported by the Italian Space Agency (ASI) under contract SERENA, No. I/090/06/0. XJ acknowledges support by the NASA Outer Planets Research Program through grant NNX12AM74G. The authors would also like to acknowledge helpful discussions with Dr. Davide Grassi. The computational resources used in this research have been supplied by INAF-IAPS through the project HPP High Performance Planetology. Dr. Diego Turrini, Dr. Romolo Politi and Dr. Vega Forneris are acknowledged for providing technical support.The H2O and O2 exospheres of Jupiter's moon Ganymede are simulated through the application of a 3D Monte Carlo modeling technique that takes into consideration the combined effect on the exosphere generation of the main surface release processes (i.e. sputtering, sublimation and radiolysis) and the surface precipitation of the energetic ions of Jupiter's magnetosphere. In order to model the magnetospheric ion precipitation to Ganymede's surface, we used as an input the electric and magnetic fields from the global MHD model of Ganymede's magnetosphere (Jia, X., Walker, R.J., Kivelson, M.G., Khurana, K.K., Linker, J.A. [2009]. J. Geophys. Res. 114, A09209). The exospheric model described in this paper is based on EGEON, a single-particle Monte Carlo model already applied for a Galilean satellite (Plainaki, C., Milillo, A., Mura, A., Orsini, S., Cassidy, T. [2010]. Icarus 210, 385-395; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Massetti, S., Cassidy, T. [2012]. Icarus 218 (2), 956-966; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Saur [2013]. Planet. Space Sci. 88, 42-52); nevertheless, significant modifications have been implemented in the current work in order to include the effect on the exosphere generation of the ion precipitation geometry determined strongly by Ganymede's intrinsic magnetic field (Kivelson, M.G. et al. [1996]. Nature 384, 537-541). The current simulation refers to a specific configuration between Jupiter, Ganymede and the Sun in which the Galilean moon is located close to the center of Jupiter's Plasma Sheet (JPS) with its leading hemisphere illuminated.
Our results are summarized as follows: (a) at small altitudes above the moon's subsolar point the main contribution to the neutral environment comes from sublimated H2O; (b) plasma precipitation occurs in a region related to the open-closed magnetic field lines boundary and its extent depends on the assumption used to mimic the plasma mirroring in Jupiter's magnetosphere; (c) the spatial distribution of the directly sputtered-H2O molecules exhibits a close correspondence with the plasma precipitation region and extends at high altitudes, being, therefore, well differentiated from the sublimated water; (d) the O2 exosphere comprises two different regions: the first one is an homogeneous, relatively dense, close to the surface thermal-O2 region (extending to some 100s of km above the surface) whereas the second one is less homogeneous and consists of more energetic O2 molecules sputtered directly from the surface after water-dissociation by ions has taken place; the spatial distribution of the energetic surface-released O2 molecules depends both on the impacting plasma properties and the moon's surface temperature distribution (that determine the actual efficiency of the radiolysis process)
ELENA DAC ramp test
No full textTest report della campagna dello strumento SERENA/ELENA a bordo di BepiColomb
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