Will the recently approved LARES mission be able to measure the LenseThirring effect at 1%?
Abstract
After the approval by the Italian Space Agency of the LARES satellite, which should be launched at the end of 2009 with a VEGA rocket and whose claimed goal is a ≈1% measurement of the general relativistic gravitomagnetic LenseThirring effect in the gravitational field of the Earth, it is of the utmost importance to reliably assess the total realistic accuracy that can be reached by such a mission. The observable is a linear combination of the nodes of the existing LAGEOS and LAGEOS II satellites and of LARES able to cancel out the impact of the first two even zonal harmonic coefficients of the multipolar expansion of the classical part of the terrestrial gravitational potential representing a major source of systematic error. While LAGEOS and LAGEOS II fly at altitudes of about 6,000 km, LARES should be placed at an altitude of 1,450 km. Thus, it will be sensitive to much more even zonals than LAGEOS and LAGEOS II. Their corrupting impact has been evaluated up to degree ℓ = 70 by using the sigmas of the covariance matrices of eight different global gravity solutions (EIGENGRACE02S, EIGENCG03C, GGM02S, GGM03S, JEM01RL03B, ITGGrace02s, ITGGrace03, EGM2008) obtained by five institutions (GFZ, CSR, JPL, IGG, NGA) with different techniques from long data sets of the dedicated GRACE missions. It turns out to be ≈1001,000% of the LenseThirring effect. An improvement of 23 orders of magnitude in the determination of the high degree even zonals would be required to constrain the bias to ≈110%.
 Publication:

General Relativity and Gravitation
 Pub Date:
 August 2009
 DOI:
 10.1007/s1071400807421
 arXiv:
 arXiv:0803.3278
 Bibcode:
 2009GReGr..41.1717I
 Keywords:

 Experimental tests of gravitational theories;
 Satellite orbits;
 Harmonics of the gravity potential field;
 General Relativity and Quantum Cosmology;
 Astrophysics;
 Physics  Geophysics;
 Physics  Space Physics
 EPrint:
 Latex, 15 pages, 1 table, no figures. Final version matching the published one in General Relativity and Gravitation (GRG)