Flux-Pinned Interfaces for the Assembly, Manipulation, and Reconfiguration of Modular Space Systems

Abstract

A b str actNon-contacting interactions between pennanent magnets and superconductors known as "flux pinning" provide a novel way to fix many modular space systems in desired relative positions and orientations. from space stations to close-proximity fonnations. When cooled appropriately, these flux-pin ned interfaces require no power or active control and very lillie mass but provide very high mechanical stiffness (>200 N/m for a few hundred grams of material) and damping (2% of critical) between modules, making the technology ideal for in-orbit assembly applications. We describe new measurements and simulations 10 characterize these values for spacecraft applications. Flux-pinned interfaces have so far achieved inter-module separations in the 8-10 em range with -100 g of mass on each module, with the prospect of larger separations. We also discuss several means to actuate the noncontacting couplers, which is a first step toward the development of devices for the noncontacting manipulation and reconfiguration of modular space systems.

A flux-pinning mechanism for segment assembly and alignment

“…While previous work has demonstrated the use of a flux-pinning mechanism for aligning CubeSats, the mechanism was not sufficiently stiff for optical alignment; the CubeSats were separated by a distance on the order of a couple centimeters, which resulted in a stiffness on the order of a few newtons per meter. 16 However, higher stiffnesses can be achieved by flux pinning the magnet and superconductor closer together or using a stronger magnet. In particular, correlated magnets, which can have a near field that is at least 50% stronger than that of an equivalent neodymium magnet, may provide a means of achieving a sufficient stiffness.…”

“…Previous investigations into flux-pinning mechanism design have focused on the application of these mechanisms as joints between spacecraft modules, 15,16 For example, to allow motion in five degrees of freedom like a wire flexure, a flux-pinning mechanism could consist of a superconductor pinned to a spherical magnet mounted in an inverted cone, as shown in Figure 2a. Since the line connecting the spherical magnet and the superconductor is an axis of symmetry for the magnetic field, the superconductor is free to rotate about this axis without disturbing the magnet.…”

A parametric finite-element model for evaluating segmented mirrors with discrete edgewise connectivity

“…Traditionally, it is challenging to add damping to a cryogenic space telescope; at such low temperatures, the material damping is negligible, and other common damping methods break down. 16,17 A flux-pinning mechanism, on the other hand, requires cryogenic temperatures to operate, and it has the additional benefit of being a non-contact mechanism. The amount of damping can also be adjusted by placing nonmagnetic conductive metals, such as aluminum, near the magnet-superconductor interface.…”

Flux-Pinned Dynamics Model Parameterization and Sensitivity Study

“…Flux-pinned interfaces leverage the dynamics of magnetic flux pinning to control the relative orientation and position of close-proximity spacecraft without mechanical contact. These unique traits make flux-pinned interfaces a technology candidate for applications such as spacecraft capture and docking 1,2 , assembly of modular systems 3,4 , formation flying [5][6][7] , kinematic mechanisms 8,9 , and station-keeping 10,11 . However, for this technology to be mature enough for spaceflight applications, its physics must be represented in a high-fidelity predictive dynamics model that can inform design trade and analyses.…”