On the Applicability of the Geodesic Deviation Equation in General Relativity

TL;DR

This paper examines the validity and limitations of the geodesic deviation equation in highly symmetric spacetimes within General Relativity, especially for satellite orbit modeling in Schwarzschild spacetime, and compares it with exact solutions.

Contribution

It analyzes the applicability of the geodesic deviation equation in Schwarzschild spacetime and assesses its accuracy against exact geodesic solutions for satellite orbit deviations.

Findings

The deviation equation accurately models satellite orbit deviations in certain regimes.

Relativistic effects cause measurable differences from Newtonian predictions.

Limitations of the first-order deviation approach are identified and discussed.

Abstract

Within the theory of General Relativity, we study the solution and range of applicability of the standard geodesic deviation equation in highly symmetric spacetimes. In the Schwarzschild spacetime, the solution is used to model satellite orbit constellations and their deviations around a spherically symmetric Earth model. We investigate the spatial shape and orbital elements of perturbations of circular reference curves. In particular, we reconsider the deviation equation in Newtonian gravity and then determine relativistic effects within the theory of General Relativity by comparison. The deviation of nearby satellite orbits, as constructed from exact solutions of the underlying geodesic equation, is compared to the solution of the geodesic deviation equation to assess the accuracy of the latter. Furthermore, we comment on the so-called Shirokov effect in the Schwarzschild spacetime and limitations of the first order deviation approach.