Decentralized Power-Optimal Coordination for Spacecraft Swarms Using Time-Varying Magnetorquer Actuation
Authors: Yuta Takahashi, Shin-ichiro Sakai
Organizations: Department of Mechanical Engineering, Institute of Science Tokyo, Tokyo, Japan · Department of Spacecraft Engineering, Japan Aerospace Exploration Agency, Kanagawa, Japan
This paper presents a decentralized power-optimal coordination framework for magnetically actuated spacecraft swarms. Swarms that form large space structures overcome the aperture limit set by the launch vehicle and hold their shape on solar-generated power alone. Magnetic actuation is propellant-free and generated by a magnetorquer, which is commonly used for attitude control. However, every spacecraft interacts with every other within range, and its effect depends on the actuation power and a carrier frequency. We therefore design a decentralized power-optimal framework to jointly derive the interaction graph, frequency grouping, and controller gains. Our decentralized controller preserves angular momentum, which is a nonholonomic constraint. Then, this framework for connected groups whose memberships overlap across carriers guarantees that the relative position errors, the absolute attitude errors, and the imbalance of the reaction-wheel momenta converge to the desired states under the decentralized power-optimal allocation. A closed-loop simulation of a thousand spacecraft with the complete alternating-current interaction confirms the framework. A fast approximate integration with a proven error bound extends the framework to a long-horizon orbital reconfiguration held with high precision.
Figures & tables
Fig. 1 : Magnetically actuated swarm reconfiguration and system diagram of grouping and controller design.
Fig. 2 : Mission energy over the neighbor distance, finite-coil correction with a minimum ratio of 0.80 in force and 0.67 in torque, and delay margin.
Algorithm 1 Agglomerative grouping.
Fig. 3 : Grouping mechanisms: (a) routing and the alignment penalty; (b) ρg per group size.
Fig. 4 : (a) Power ratio over the alignment weight wa . (b) Mission ratio W(n=2)/W(Method) .
Clique
Med.
Max
Mission
Med.
Max
3-clique
1.75
2.9
Inv. K=102
0.79
0.94
4-clique
2.42
5.1
Inv. K=105
0.93
0.94
5-clique
4.02
9.0
ODA n=2
1.00
1.00
Octahedron
3.19
6.3
Grp. n=4
1.39
15.9
TABLE I : Power ratios J(Z(2))/J(Z(n)) on isolated cliques and W(Z(2))/W(method) .
Fig. 5 : The terminal formation representing the Tokyo Tower (Tokyo Digital Twin Project, CC-BY).
n=2
n=3
n=4
Power gain (median)
1.15×
1.34×
1.58×
Power gain (range)
1.05 – 1.94×
1.23 – 2.29×
1.39 – 2.78×
Error gain (median)
1.04×
1.28×
1.54×
Error gain (10–90%)
0.40 – 2.50×
0.58 – 2.94×
0.76 – 3.67×
Lower error
54%
73%
83%
TABLE II : Gain over the best-of- K inverse allocation ( K=1000 ) in the closed-loop sweep, total power per frame and time-averaging error per spacecraft.
Figure 9
n=2
n=3
n=4
n=5
n=6
n=7
Count
130598
97483
60378
37857
22966
13291
Mean
1.000
1.110
1.218
1.315
1.382
1.431
Std
0.000
0.128
0.190
0.228
0.237
0.239
Max
1.000
1.533
1.812
2.006
2.087
2.133
TABLE III : Empirical certificate γW=WODA/Jdual .
Fig. 8 : Orbital reconfiguration of 64 spacecraft ( y along-track, z normal, viewed from the radial direction).
This correspondence presents a convex-optimization-based evaluation framework of satellite-swarm-based apertures maintained by magnetic-field interactions. Spaceborne distributed apertures are composed of multiple satellites and are attractive for scientific and commercial missions because their scalability enables high-gain, narrow-beam, and large-aperture capabilities beyond the launch-size limitations. A key challenge is that the long-term maintenance of such virtual structures requires consistent formation control amid unstable orbital dynamics, and magnetic interactions generated by satellite-mounted magnetorquers offer a desirable propellant-free position-control strategy. However, the nonlinearities of the electromagnetic force and torque model lead to a nonconvex power-consumption constraint, making system-level configuration analysis difficult. To address this issue, we develop a convex optimization-based framework to analyze the power consumption of large magnetically actuated satellite swarms. The resulting analysis shows that increasing the number of satellites can improve formation-keeping power efficiency. This indicates that magnetically actuated swarm architectures provide a power-efficient alternative to the conventional few-satellite electromagnetic formation-flight concept for constructing large-scale space systems.
Yuta Takahashi, Seang Shim, Hiraku Sakamoto +1
Mechanical Engineering, Institute of Science Tokyo, Meguro-ku, Tokyo 152-8550, Japan · Department of Space and Astronautical Science, The Graduate University for Advanced Studies, Sagamihara, Kanagawa 252-5210, Japan · Spacecraft Engineering, Institute of Space and Astronautical Science, Sagamihara, Kanagawa 252-5210, Japan
Spacecraft attitude control is traditionally achieved using momentum exchange devices or propellant-consuming thrusters. Meanwhile, a growing number of missions require robotic manipulators, which are typically treated as disturbance sources to be rejected rather than as actuators for spacecraft reorientation. This work investigates the use of manipulator motions for propellant-free attitude control by formulating a trajectory optimization problem with critical joint and collision avoidance constraints. Using an interior point solver for the resulting nonlinear program, complex slew and detumble trajectories are demonstrated for a range of spacecraft-manipulator systems with varying kinematic complexity and mass properties. The achievable control authority is compared directly with that of reaction wheel arrays via momentum and torque envelopes, demonstrating the potential for manipulators to serve as redundant or even primary attitude control systems. This work provides a framework for using manipulators as multipurpose attitude control actuators, with particularly promising applications in in-space assembly and manufacturing when grasping payloads with high relative mass fractions.
Harsh G. Bhundiya, Avi Soval, Keenan Albee
Department of Astronautical Engineering, University of Southern California, Los Angeles, CA 90089 · Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089 · Departments of Astronautical, Aerospace and Mechanical, and Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089
Decentralized multi-agent swarm coordination on resource-constrained edge platforms remains fundamentally bottlenecked by the exponential scaling of joint action spaces and high-latency communication overhead. This paper introduces the Swarm Policy Interference Network (SPIN) framework, an architectural paradigm that bypasses these limitations by modeling swarm topologies as a compressed tensor network. We factorize the joint policy tensors of local multi-agent cliques into Matrix Product State (MPS) chains, reducing the computational complexity of evaluation from an exponential O(nm) wall to a strictly linear O(m⋅n⋅χ2) constraint. To bridge local continuous spatial geometry with this discrete algebraic backend without requiring power-intensive online training loops, we introduce a decoupled, hybrid neuro-symbolic control pipeline. Local multi-layered neural networks operate as structural coordination encoders, pre-trained offline to nonlinearly map hand-engineered geometric descriptors into abstract environmental target measures. At runtime, edge agents execute instantaneous behavioral adaptations by applying the Radon-Nikodým derivative directly as a zero-shot importance-reweighting filter. We validate the framework within a discrete-time multi-agent simulation sandbox spanning tracking, decentralized dispersion/area coverage, and multi-goal coordination regimes. Qualitative telemetry demonstrates that the integrated pipeline achieves stable target-directed motion, anti-collapse spatial spreading under decentralized constraints, and structured subgroup formation across multiple targets, providing a mathematically grounded route to tractable, low-power edge swarm intelligence.