HRWS - An Ambitious 4+ Satellite Formation Flying Mission

Abstract

High Resolution Wide Swath (HRWS) is an ambitious Synthetic Aperture Radar (SAR) mission proposed by Airbus Defence and Space, which will potentially exploit formation flight and the novel MirrorSAR concept to achieve unprecedented imaging characteristics by means of fractionated radar architecture, Ref. [1] and [2]. Originally planned as a follow-on of the extremely successful TerraSAR-X project, the HRWS mission and the satellite itself gradually took on a very different form, as the scientific goals grew more and more challenging. Now to be possibly equipped with electric propulsion and more than 3 times heavier than TerraSAR-X, the HRWS satellite is to be maintained within the control tube of merely 100 m (desired minimum) to maximum 250 m radius around the repeat ground-track reference orbit. On top of that, it is planned to augment the mission by 3 to 4 low-cost companion satellites flying in close proximity (down to ~100 m) to one another. Altogether, these challenges call for a very careful consideration of the absolute and relative orbit control concepts in order to develop a safe and precise maneuver strategy.