28 research outputs found
Phenomenology of the Lense-Thirring effect in the Solar System
Recent years have seen increasing efforts to directly measure some aspects of
the general relativistic gravitomagnetic interaction in several astronomical
scenarios in the solar system. After briefly overviewing the concept of
gravitomagnetism from a theoretical point of view, we review the performed or
proposed attempts to detect the Lense-Thirring effect affecting the orbital
motions of natural and artificial bodies in the gravitational fields of the
Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of
the impact of several sources of systematic uncertainties of dynamical origin
to realistically elucidate the present and future perspectives in directly
measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in
Astrophysics and Space Science (ApSS). Some uncited references in the text
now correctly quoted. One reference added. A footnote adde
An Assessment of the Systematic Uncertainty in Present and Future Tests of the Lense-Thirring Effect with Satellite Laser Ranging
We deal with the attempts to measure the Lense-Thirring effect with the
Satellite Laser Ranging (SLR) technique applied to the existing LAGEOS and
LAGEOS II terrestrial satellites and to the recently approved LARES
spacecraft.The first issue addressed here is: are the so far published
evaluations of the systematic uncertainty induced by the bad knowledge of the
even zonal harmonic coefficients J_L of the multipolar expansion of the Earth's
geopotential reliable and realistic?
Our answer is negative. Indeed, if the differences Delta J_L among the even
zonals estimated in different Earth's gravity field global solutions from the
dedicated GRACE mission are assumed for the uncertainties delta J_L instead of
using their covariance sigmas sigma_JL, it turns out that the systematic
uncertainty \delta\mu in the Lense-Thirring test with the nodes Omega of LAGEOS
and LAGEOS II may be up to 3 to 4 times larger than in the evaluations so far
published () based on the use of the sigmas of one model at a time
separately. The second issue consists of the possibility of using a different
approach in extracting the relativistic signature of interest from the
LAGEOS-type data. The third issue is the possibility of reaching a realistic
total accuracy of 1% with LAGEOS, LAGEOS II and LARES, which should be launched
in November 2009 with a VEGA rocket. While LAGEOS and LAGEOS II fly at
altitudes of about 6000 km, LARES will be likely placed at an altitude of 1450
km. Thus, it will be sensitive to much more even zonals than LAGEOS and LAGEOS
II. Their corrupting impact has been evaluated with the standard Kaula's
approach up to degree L=60 by using Delta J_L and sigma_JL; it turns out that
it may be as large as some tens percent.Comment: LaTex, 19 pages, 1 figure, 12 tables. Invited and refereed
contribution to The ISSI Workshop, 6-10 October 2008, on The Nature of
Gravity Confronting Theory and Experiment in Space To appear in Space Science
Review