18,255 research outputs found
Testing Gravitation in the Solar System with Radio Science experiments
The laws of gravitation have been tested for a long time with steadily
improving precision, leading at some moment of time to paradigmatic evolutions.
Pursuing this continual effort is of great importance for science. In this
communication, we focus on Solar System tests of gravity and more precisely on
possible tests that can be performed with radio science observations (Range and
Doppler). After briefly reviewing the current tests of gravitation at Solar
System scales, we give motivations to continue such experiments. In order to
obtain signature and estimate the amplitude of anomalous signals that could
show up in radio science observables because of modified gravitational laws, we
developed a new software that simulates Range/Doppler signals. We present this
new tool that simulates radio science observables directly from the space-time
metric. We apply this tool to the Cassini mission during its cruise from
Jupiter to Saturn and derive constraints on the parameters entering alternative
theories of gravity beyond the standard Parametrized Post Newtonian theory.Comment: proceedings of SF2A 2011 - minor changes (typos corrected -
references updated
Viking radio science data analysis and synthesis
Viking radio data analysis and synthesis was used for the following: (1) Solar System Model and Data Set; (2) Rotation of Mars; and (3) Solar System Constants and Tests of Relativity
Parkes radio science system design and testing for Voyager Neptune encounter
The Radio Science System installed at Parkes, Australia for the Voyager Neptune encounter was specified to meet the same stringent requirements that were imposed upon the Deep Space Network Radio Science System. The system design and test methodology employed to meet these requirements at Parkes are described, and data showing the measured performance of the system are presented. The results indicate that the system operates with a comfortable margin on the requirements. There was a minor problem with frequency-dependent spurious signals which could not be fixed before the encounter. Test results characterizing these spurious signals are included
Millimeter-Wave Over-the-Air Signal-to-Interference-plus-Noise-Ratio Measurements Using a MIMO Testbed
In this paper, over-the-air experiments with external and internal
interferences were performed using Chalmers millimeter-wave
multiple-input-multiple-output testbed MATE. The resulting SINR for both
interference experiments are compared and discussed.Comment: 2nd URSI Atlantic Radio Science Meeting (URSI AT-RASC 2018
Data catalog series for space science and applications flight missions. Volume 1A: Brief descriptions of planetary and heliocentric spacecraft and investigations
Planetary and heliocentric spacecraft, including planetary flybys and probes, are described. Imaging, particles and fields, ultraviolet, infrared, radio science and celestial mechanics, atmospheres, surface chemistry, biology, and polarization are discussed
The Reactive Energy of Transient EM Fields
We give a physically compelling definition of the instantaneous reactive
energy density associated with an arbitrary transient electromagnetic field in
vacuum.Comment: 2 pages, 2 figures. Summary of a talk given at the 2012 IEEE
International Symposium on Antennas and Propagation and USNC-URSI National
Radio Science Meeting, Session 563, July 13, 201
On the Juno Radio Science Experiment: models, algorithms and sensitivity analysis
Juno is a NASA mission launched in 2011 with the goal of studying Jupiter.
The probe will arrive to the planet in 2016 and will be placed for one year in
a polar high-eccentric orbit to study the composition of the planet, the
gravity and the magnetic field. The Italian Space Agency (ASI) provided the
radio science instrument KaT (Ka-Band Translator) used for the gravity
experiment, which has the goal of studying the Jupiter's deep structure by
mapping the planet's gravity: such instrument takes advantage of synergies with
a similar tool in development for BepiColombo, the ESA cornerstone mission to
Mercury. The Celestial Mechanics Group of the University of Pisa, being part of
the Juno Italian team, is developing an orbit determination and parameters
estimation software for processing the real data independently from NASA
software ODP. This paper has a twofold goal: first, to tell about the
development of this software highlighting the models used, second, to perform a
sensitivity analysis on the parameters of interest to the mission.Comment: Accepted for publication in MONTHLY NOTICES of the Royal Astronomical
Society 2014 October 31. Received 2014 July 28; in original form 2013 October
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The depth of the convective boundary layer and implications for a Walker-like circulation on Mars
Radio science observations indicate that the depth of the martian convective boundary layer varies strongly with surface height, although the surface temperature does not. We show that this effect is reproduced in martian limited area models and in global climate models. The implications for the global circulation when convective boundary layer depth varies with location are considered
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