Recent Developments in Gravity Gradiometry from the Space Shuttle-Borne Tethered Satellite System

Abstract - This paper describes the current development of a noncryogenic gravity gradiometer for future use on board the tethered satellite system (TSS). The paper also proposes a way of testing a single‐axis prototype of such an instrument that makes use of the free‐fall technique in vacuum. This gravity gradiometer has a design sensitivity of the order of 10^-2 EU (1 EU =Eötvös Unit=10^-9 ms-2/m) in 10‐s integration time. Because of the small size and light weight, a noncryogenic gravity gradiometer is a valid candidate to fit the limited accommodation capability of the TSS deployed from the shuttle and maintained, for several days, at an altitude of 120–130 km. This unique capability improves the resolution and accuracy achievable in reconstructing the earth gravity field, in particular at short wavelengths. A preliminary analysis of the dynamics of the TSS satellite indicates the potential of such satellite as a low‐altitude research platform for gravity gradiometry.