OA@INAFhttps://openaccess.inaf.itThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 26 May 2024 20:47:59 GMT2024-05-26T20:47:59Z5041A 1% Measurement of the Gravitomagnetic Field of the Earth with Laser-Tracked Satelliteshttp://hdl.handle.net/20.500.12386/31453Title: A 1% Measurement of the Gravitomagnetic Field of the Earth with Laser-Tracked Satellites
Authors: LUCCHESI, David; VISCO, Massimo; PERON, ROBERTO; Bassan, M; Pucacco, G; Pardini, C; Anselmo, L; MAGNAFICO, Carmelo
Abstract: A new measurement of the gravitomagnetic field of the Earth is presented. The measurement has been obtained through the careful evaluation of the Lense-Thirring (LT) precession on the combined orbits of three passive geodetic satellites, LAGEOS, LAGEOS II, and LARES, tracked by the Satellite Laser Ranging (SLR) technique. This general relativity precession, also known as frame-dragging, is a manifestation of spacetime curvature generated by mass-currents, a peculiarity of Einstein’s theory of gravitation. The measurement stands out, compared to previous measurements in the same context, for its precision (≃7.4×10−3, at a 95% confidence level) and accuracy (≃16×10−3), i.e., for a reliable and robust evaluation of the systematic sources of error due to both gravitational and non-gravitational perturbations. To achieve this measurement, we have largely exploited the results of the GRACE (Gravity Recovery And Climate Experiment) mission in order to significantly improve the description of the Earth’s gravitational field, also modeling its dependence on time. In this way, we strongly reduced the systematic errors due to the uncertainty in the knowledge of the Earth even zonal harmonics and, at the same time, avoided a possible bias of the final result and, consequently, of the precision of the measurement, linked to a non-reliable handling of the unmodeled and mismodeled periodic effects.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/20.500.12386/314532020-01-01T00:00:00ZBepiVR: Virtual Reality for BepiColombo outreachhttp://hdl.handle.net/20.500.12386/32575Title: BepiVR: Virtual Reality for BepiColombo outreach
Authors: POLITI, ROMOLO; SIMIONI, EMANUELE; CREMONESE, Gabriele; GALLUZZI, VALENTINA; MAGNAFICO, Carmelo; MANGANO, VALERIA; De Marchi, Fabrizio; RE, Cristina; Romano, Domenico
Abstract: Description of the project of a VR application for smartphone on the mission BepiColombo and the exploration of the planet Mercury
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/20.500.12386/325752018-01-01T00:00:00ZGeneral Relativity Measurements in the Field of Earth with Laser-Ranged Satellites: State of the Art and Perspectiveshttp://hdl.handle.net/20.500.12386/30070Title: General Relativity Measurements in the Field of Earth with Laser-Ranged Satellites: State of the Art and Perspectives
Authors: LUCCHESI, David; Anselmo, Luciano; Bassan, Massimo; MAGNAFICO, Carmelo; Pardini, Carmen; PERON, ROBERTO; Pucacco, Giuseppe; VISCO, Massimo
Abstract: Recent results of the LARASE research program in terms of model improvements and
relativistic measurements are presented. In particular, the results regarding the development of
new models for the non-gravitational perturbations that affect the orbit of the LAGEOS and LARES
satellites are described and discussed. These are subtle and complex effects that need a deep
knowledge of the structure and the physical characteristics of the satellites in order to be correctly
accounted for. In the field of gravitational measurements, we present a new measurement of the
relativistic Lense-Thirring precession with a 0.5% precision. In this measurement, together with
the relativistic effect we also estimated two even zonal harmonics coefficients. The uncertainties of
the even zonal harmonics of the gravitational field of the Earth have been responsible, until now,
of the larger systematic uncertainty in the error budget of this kind of measurements. For this
reason, the role of the errors related to the model used for the gravitational field of the Earth in these
measurements is discussed. In particular, emphasis is given to GRACE temporal models, that strongly
help to reduce this kind of systematic errors.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/20.500.12386/300702019-01-01T00:00:00ZThe LARASE Spin Model of the two LAGEOS and LARES satelliteshttp://hdl.handle.net/20.500.12386/25945Title: The LARASE Spin Model of the two LAGEOS and LARES satellites
Authors: VISCO, Massimo; LUCCHESI, David; Anselmo, Luciano; Bassan, Massimo; MAGNAFICO, Carmelo; Nobili, Anna Maria; Pardini, Carmen; PERON, ROBERTO; Pucacco, Giuseppe; STANGA, RUGGERO
Abstract: Satellite Laser Ranging (SLR) represents a very important technique of the observational space geodesy. In fact, Lunar Laser Ranging, Very Long Baseline Interferometry, Global Navigation Satellite Systems, Doppler Orbitography and Radiopositioning Integrated by Satellite, together with SLR constitute the Global Geodetic Observing System (GGOS). In the context of the GGOS activities, improvements in technology and in modeling will produce advances in Geodesy and Geophysics as well as in General Relativity (GR) measurements. Therefore, these important research fields are not independent, but tightly related to each other. The LARASE (LAser RAnged Satellites Experiment) research program has its main objectives in tests and measurements of Einstein's theory of GR via Precise Orbit Determination (POD) of a set of geodetic satellites. In order to reach such goals by means of very precise measurements of a number of relativistic parameters (and, at the same time, to provide a robust and unassailable error budget of the main systematic effects), we are also reviewing previous models and we are developing new models for the main perturbations (both gravitational and non-gravitational) that act on the orbits of the two LAGEOS and on that of LARES satellites. Within this paper we focus on modeling the spin vector of these satellites. The spin knowledge, both in orientation and rate, is of fundamental importance in order to correctly model the thermal effects acting on the surface of these satellites. These are very important non-gravitational perturbations (NGP) that produce long-term effects on the orbit of the cited satellites, especially for the two LAGEOS, and improvements in their modeling will be very useful both in the field of GR measurements and in those of space geodesy and geophysical applications. Indeed, the current RMS value of the range residuals of the LAGEOS satellites, obtained by the Analysis Centers of the International Laser Ranging Service, is at the level of a few cm since 1992, down to a cm or less during the last years. However, because of the incompleteness in current knowledge of dynamical models, empirical accelerations have been heavily employed to obtain such results. In this context, any step forward in the models developed for the NGP will be useful to reduce the use of empirical accelerations; it also represents an essential prerequisite to reach a sub-mm precision in the RMS of the SLR range residuals and the corresponding benefits in Geophysics and Geodesy, regarding e.g. stations coordinates knowledge, Earth's geocenter and reference frame realization. The paper will focus upon the improvements we obtained with respect on previous models of the spin of the two LAGEOS satellites based on averaged equations for the external torques in the rapid-spin approximation, as well as in a new general model that we developed and based on the solution of the full set of Euler equations.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/20.500.12386/259452016-01-01T00:00:00Z