An Improved Next Generation Gravity Mission

Peter L. Bender

doi:10.3390/rs14040948

Abstract

There is an opportunity to make a major reduction in the acceleration noise level for the first Next Generation Gravity Mission by replacing the accelerometers used on the GRACE Follow-On Mission by a highly simplified version of the Gravitational Reference Sensors flown very successfully on the LISA Pathfinder mission of ESA. The reduced measurement noise level can make possible much-improved measurements of the short-period and short-wavelength variations in the geopotential. This would be particularly from the along-track analysis of the results, which can permit repeat measurements about half a day apart along ground tracks within 200 km of each other over a substantial part of the globe. Such a mission would permit considerably improved testing of geophysical models for the geopotential variations due to changes in the Earth’s mass distribution.

Highlights

The accelerometers flown on the GRACE and GRACE Follow-On missions would be replaced by the highly simplified gravitational reference sensors being developed under NASA support [4,5]
The satellite orbit inclination is assumed to be within 0.1 deg of polar, and the altitude is chosen to be somewhat lower than the early altitude for GRACE Follow-On
The enhanced measurement accuracy would be valuable in comparing different geophysical models for the geopotential variations, and in understanding the basic geophysics involved better

Summary

Introduction

The measurement accuracy improvement from using laser interferometry rather than microwave ranging between satellites to determine changes in their separation has been clearly demonstrated on the GRACE Follow-On mission [6]. For determining global averages of the geopotential changes over periods of 10 days or longer, the main limitation on the usefulness of the possible much-improved instrumental measurement accuracy comes from temporal aliasing.

Results

Conclusion