1,720,995 research outputs found
Contribution of LARES and geodetic satellites on environmental monitoring
No full textLARES is the latest laser ranged geodetic satellite launched in orbit. It is an Italian Space Agency mission devoted mainly to test fundamental physics. However, it will be shown in the present paper that it will also contribute significantly to Earth science. The use of LARES together with the constellation of the other geodetic satellites will provide improvements in the measurement of the gravity field of Earth including its temporal variation measurements. In particular the latter carries signatures of mass redistribution due to several phenomena including global atmospheric and oceanic circulation, useful not only for monitoring global climate change but also to provide a means for climate model validation
El Niño effects on earth rotation parameters from LAGEOS and LARES orbital analysis
No full textEarth rotation, besides external actions due to other bodies in the solar system, is influenced by internal mass redistributions, including its atmospheric and water envelope. EI Nifio-Southern Oscillation (ENSO) is one such event characterized by sea level change in the eastern part of the Pacific Ocean due to an increase of the temperature by about 2°C. ENSO is manifested with irreguIar periodicity and with different strength. SateIIite Laser Ranging (SLR) to orbiting satellites such as LAGEOS and LARES in conjunction with the other geodedic techniques, such as GNSS and Very Long Baseline Interferometry (VLBI), allow very accurate determination of the center of mass and rotation vector of the Earth. The paper will report on the experimental vaIues of the Earth orientation parameters and in particuIar of the center of mass and the Iength of the day with particuIar reference to signatures due to last ENSO event ended in 2016
Quality assessment of LARES satellite ranging data
No full textLARES is an Italian Space Agency mission designed to test General Relativity in the weak field of Earth. In particular, the satellite will be able to measure frame-dragging with an accuracy of about 1%. The difficulty of the measurement is mainly due to the perturbations acting on the satellite and the relatively tiny size of the effect, amounting to about 118 milliarcseconds/year. LARES will also provide data to geodesists and it will contribute to GNSS by improving the origin definition of the International Terrestrial Reference Frame. The mission was designed and the satellite subsystems built and tested in less than four years. The short time to launch and the very limited budget of the LARES mission, raised doubts whether LARES could be, as expected by design, one of the best satellite laser ranging targets. The best way to confirm the success of the mission is to look at the range residuals from the primary stations of the International Laser Ranging Service (ILRS). In the paper it will be shown that from the majority of these stations LARES behaves as the best target
Studies on the materials of LARES 2 satellite
No full textLARES 2 is an Italian Space Agency (ASI) satellite designed for testing with unprecedented accuracy frame-dragging, a fundamental prediction of general relativity, for other tests of fundamental physics and to contribute to space geodesy with a precision higher than any other satellite presently in orbit. The choice of the material for the body of LARES 2 satellite determines, along with its dimensions, the surface-to-mass ratio minimization, which is the main requirement for the satellite. The paper will report the studies conducted for the fulfillment of the above-mentioned requirement and the tests performed to qualify the materials for construction of the satellite
A new laser-ranged satellite for General Relativity and space geodesy: II. Monte Carlo simulations and covariance analyses of the LARES 2 experiment
No full textIn the previous paper we have introduced the LARES 2 space experiment. The LARES 2 laser-ranged satellite is planned for a launch in 2019 with the new VEGA C launch vehicle of the Italian Space Agency (ASI), ESA and ELV. The main objectives of the LARES 2 experiment are accurate measurements of General Relativity, gravitational and fundamental physics and accurate determinations in space geodesy and geodynamics. In particular LARES 2 is aimed to achieve a very accurate test of frame-dragging, an intriguing phenomenon predicted by General Relativity. Here we report the results of Monte Carlo simulations and covariance analyses fully confirming an error budget of a few parts in one thousand in the measurement of frame-dragging with LARES 2 as calculated in our previous paper
Tests of General Relativity with the LARES Satellites
No full textLARES (LAser RElativity Satellite) developed by the Italian Space Agency (ASI) is a laser-ranged satellite successfully launched in February 2012 by ESA (European Space Agency). A second ASI laser-ranged satellite, LARES 2, is scheduled for launch by ESA at the end of 2019. Here we describe the main scientific objectives achieved and achievable by LARES and LARES 2, both in General Relativity and in space geodesy and geodynamics. Among the main tests achieved by LARES is a 5% test of frame-dragging, a fundamental and intriguing prediction of General Relativity. The LARES 2 satellite together with the laser-ranged satellite LAGEOS of NASA, is aimed to provide a 0.2% test of frame-dragging together with other relevant tests and determinations in fundamental physics, space geodesy and geodynamics
Satellite Laser-Ranging as a Probe of Fundamental Physics
Full text linkSatellite laser-ranging is successfully used in space geodesy, geodynamics and Earth sciences; and to test fundamental physics and specific features of General Relativity. We present a confirmation to approximately one part in a billion of the fundamental weak equivalence principle ("uniqueness of free fall") in the Earth's gravitational field, obtained with three laser-ranged satellites, at previously untested range and with previously untested materials. The weak equivalence principle is at the foundation of General Relativity and of most gravitational theories
Orbital predictions for the LARES satellite mission
No full textLARES is an Italian Space Agency satellite specifically designed, built and launched to test general relativity. It is a passive satellite covered with Cube Corner Reflectors that reflect laser pulses from tracking stations, thus allowing accurate measurement of the distance. That in turn enables accurate orbit reconstruction that is a key ingredient to allow the measurement of the tiny Lense-Thirring effect predicted by general relativity. The International Space Time Analysis Research Center provides the International Laser Ranging Service-ILRS, the orbital predictions for LARES for pointing of the tracking telescopes toward the target. The paper describes the technical aspects of generating the orbital predictions
Studies on the materials of LARES 2 satellite
No full textLARES 2 is an Italian Space Agency (ASI) satellite designed for testing with unprecedented accuracy frame-dragging, a fundamental prediction of general relativity, for other tests of fundamental physics and to contribute to space geodesy with a precision higher than any other satellite presently in orbit. The choice of the material for the body of LARES 2 satellite determines, along with its dimensions, the surface-to-mass ratio minimization, which is the main requirement for the satellite. The paper will report the studies conducted for the fulfillment of the above-mentioned requirement and the tests performed to qualify the materials for construction of the satellite
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