A Concept for Capturing and Docking Spacecraft with Flux-Pinned Interfaces

Abstract

Flux-pinned interfaces for spacecraft leverage the physics of magnetic flux pinning to govern the dynamics between close-proximity spacecraft. The behavior of this interface enables a magnet to be held at a distance in up to six degrees of freedom relative to a type-II superconductor without contact or active control systems. This behavior is the result of a magnetic potential well with an equilibrium set by designer of the interface. When applied to a conceptual sample capture scenario, this approach offers several unique advantages over traditional mechanical capture systems, including robustness to control failures and the ability to preferentially orient the capture target without mechanical keying features. However, as a passive system, it is important to characterize the depth and shape of the potential well in order to bound the acceptable relative motion between a notional spacecraft and a notional sample cache to ensure a successful capture. This paper presents the results of a series of air bearing experiments designed to determine these bounds. Extrapolating from the ground testing environment, it was determined that the FPI is expected to work at a range of 50 cm in orbit around Mars, and operates best in a path angle of 0 degrees. It can tolerate a total relative translational velocity of up to 4.7 cm/sec or a total angular rate of 24 deg/sec between a spacecraft and a sample cache.