Compute System Organization for High Frequency High Order Wavefront Sensing and Control

TL;DR

This paper proposes offloading high-order wavefront sensing and control computations to a dedicated satellite at Sun-Earth L2, enabling higher control frequencies and improved wavefront stability for space telescopes.

Contribution

It introduces a novel architecture using a co-flying compute satellite to meet the demanding computational needs of high-precision wavefront control.

Findings

Offloading to a dedicated satellite increases control cadence to hundreds of hertz.

Custom hardware architectures can reduce power consumption while maintaining high performance.

System-level considerations for satellite integration are outlined.

Abstract

Maintaining long-term wavefront stability is critical for the Habitable Worlds Observatory (HWO), which targets contrasts approaching $10^{-10}$ and therefore requires continuous dark-zone maintenance using high-order wavefront sensing and control (HOWFSC). Prior work has advanced HOWFSC algorithms and profiled candidate implementations on radiation-hardened processors, highlighting a substantial gap between the computational demands of LUVOIR-scale HOWFSC and the capabilities of current onboard spacecraft hardware. In this paper, we argue that this gap can be closed by offloading the HOWFSC pipeline to a dedicated co-flying compute satellite at Sun-Earth L2. This approach enables the use of modern, radiation-tolerant high-performance processors without increasing risk to the primary observatory. We show that such an architecture can increase the end-to-end control cadence from the sub-hertz regime typical of radiation-hardened onboard processing or ground-in-the-loop operation to tens and even hundreds of hertz. We evaluate commercial hardware platforms in terms of performance and feasibility, and we propose custom architectures that enable higher control frequencies with significant power consumption reductions. Finally, we outline system-level considerations for co-flying compute, including reliability, satellite integration, and inter-satellite communication constraints.