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Main Authors: Fang, Yuzhou, Zhang, Xuefeng, Li, Hongyin
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.14552
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author Fang, Yuzhou
Zhang, Xuefeng
Li, Hongyin
author_facet Fang, Yuzhou
Zhang, Xuefeng
Li, Hongyin
contents TianQin is a dedicated geocentric mission for space-based gravitational wave (GW) detection. Among its core technologies, the drag-free and pointing control subsystem (DFPCS) - consisting of suspension, drag-free and pointing controls - keeps the two test masses (TMs) centered and aligned within their housings while maintaining drag-free conditions and precise telescope pointing along the laser-arm directions. This results in orbit-attitude coupled dynamics for the constellation. The coupling is made more prominent due to satellite self-gravity, which requires compensation from DFPCS and generally makes the satellites deviate from pure free-fall orbits. Previous studies assumed that the orbit and attitude dynamics could be decoupled in numerical simulation, neglecting the back-action from the closed-loop control to orbit propagation. To address this, we develop a comprehensive model that can propagate the full 9-body (6 TMs + 3 satellites, orbits and attitudes) dynamics inter-dependently under the inter-satellite pointing and drag-free conditions. This paper is threefold. First, we reassess the applicability of the two TMs and telescope pointing scheme to TianQin using the new model, and confirm the previous conclusion. Second, to meet the constellation stability requirements, it is found that the DC common self-gravity in the flight direction should be minimized, or kept close for the three satellites. Finally, we simulate the long-range light path between two TMs/satellites with a precision of sub-pm/Hz$^{1/2}$, and the results support the decoupling of the closed-loop dynamics and high-precision orbit for computational efficiency. The method is instrumental to other future missions where the orbit-attitude coupling needs careful consideration.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14552
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modeling coupled constellation dynamics for TianQin under self-gravity
Fang, Yuzhou
Zhang, Xuefeng
Li, Hongyin
General Relativity and Quantum Cosmology
Instrumentation and Methods for Astrophysics
TianQin is a dedicated geocentric mission for space-based gravitational wave (GW) detection. Among its core technologies, the drag-free and pointing control subsystem (DFPCS) - consisting of suspension, drag-free and pointing controls - keeps the two test masses (TMs) centered and aligned within their housings while maintaining drag-free conditions and precise telescope pointing along the laser-arm directions. This results in orbit-attitude coupled dynamics for the constellation. The coupling is made more prominent due to satellite self-gravity, which requires compensation from DFPCS and generally makes the satellites deviate from pure free-fall orbits. Previous studies assumed that the orbit and attitude dynamics could be decoupled in numerical simulation, neglecting the back-action from the closed-loop control to orbit propagation. To address this, we develop a comprehensive model that can propagate the full 9-body (6 TMs + 3 satellites, orbits and attitudes) dynamics inter-dependently under the inter-satellite pointing and drag-free conditions. This paper is threefold. First, we reassess the applicability of the two TMs and telescope pointing scheme to TianQin using the new model, and confirm the previous conclusion. Second, to meet the constellation stability requirements, it is found that the DC common self-gravity in the flight direction should be minimized, or kept close for the three satellites. Finally, we simulate the long-range light path between two TMs/satellites with a precision of sub-pm/Hz$^{1/2}$, and the results support the decoupling of the closed-loop dynamics and high-precision orbit for computational efficiency. The method is instrumental to other future missions where the orbit-attitude coupling needs careful consideration.
title Modeling coupled constellation dynamics for TianQin under self-gravity
topic General Relativity and Quantum Cosmology
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2502.14552