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arXiv · 2606.21274

Nested active pointing control for interspacecraft laser interferometry

Daikang Wei·Christoph Bode·Yihao Yan·Vitali Müller·Juan José Esteban Delgado·Gerhard Heinzel
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Abstract

Precise pointing control is a critical requirement for interspacecraft laser interferometry, as angular misalignment introduces measurement noise and even leads to laser link loss. We present a nested control architecture that uses differential wavefront sensing signals to drive a fast steering mirror (FSM) to track the incoming beam, while feeding the FSM's angular changes back to the attitude and orbit control system (AOCS) to suppress angle-dependent optical path variations. This scheme is experimentally validated in our hexapod-based setup. Relative to standalone FSM actuation, the nested configuration enhanced pointing stability by 6.9 dB and 4.9 dB in the horizontal and vertical directions across the frequency band from 3 mHz to the AOCS actuation's unity-gain frequency. Additionally, tilt-to-length coupling was suppressed by an order of magnitude below 6 mHz and by two orders of magnitude below 0.45 mHz. These results demonstrate the feasibility of nested active pointing control for future interspacecraft laser interferometry missions.

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Daikang Wei, Christoph Bode, Yihao Yan, Vitali Müller, Juan José Esteban Delgado, Gerhard Heinzel. 2026-06-19. Nested active pointing control for interspacecraft laser interferometry. https://arxiv.org/abs/2606.21274

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