Satellite non-gravitational orbital perturbations and the detection of the gravitomagnetic clock effect

摘要

The general relativistic gravitomagnetic clock effect consists in the factthat two massive test bodies orbiting a central spinning mass in its equatorialplane along two identical circular trajectories, but in opposite directions,take different times in describing a full revolution with respect to anasymptotically inertial observer. In the field of the Earth such time shiftamounts to 10^{-7} s. Detecting it by means of a space based mission withartificial satellites is a very demanding task because there are severeconstraints on the precision with which the radial and azimuthal positions of asatellite must be known: delta r= 10^{-2} cm and delta phi= 10^{-2}milliarcseconds per revolution. In this paper we assess if the systematicerrors induced by various non-gravitational perturbations allow to meet suchstringent requirements. A couple of identical, passive laser-ranged satellitesof LAGEOS type with their spins aligned with the Earth's one is considered. Itturns out that all the non vanishing non-gravitational perturbations inducesystematic errors in r and phi within the required constraints for a reasonableassumption of the mismodeling in some satellite's and Earth's parameters and/orby using dense satellites with small area-to-mass ratio. However, the error inthe Earth's GM is by far the largest source of uncertainty in the azimuthallocation which is affected at a level of 1.2 milliarcseconds per revolution.