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Experiment Design

Project RAGNAR

This experiment will demonstrate an autonomous docking maneuver between two freefloating nanosatellite-scale spacecraft modules using magnetic flux pinning for actuation. A fluxpinned interface will create a passively stable equilibrium and establish a non-contacting connection between the two modules that resists environmental perturbations. Once this maneuver is complete, a feedback control loop will use electromagnets to control the two bodies to a reference position and orientation. In addition, the experiment will provide data to characterize the Jacobian of the flux pinning interaction simultaneously in all six degrees of freedom, including coupled motions.

The nanosat-scale mockup modules will be designed for ease of use during the experiment and the ability to quickly swap out components for performing new experiments. The hardware is built around a card and shell design, where the electronics, actuators, and other systems unique to each experiment are housed on a simple card of material. These cards can be quickly inserted and removed into the structural shell which provides support and protection for the experimental hardware. Through the use of dovetail joints, spring-loaded latches, and quick release pins, the cards and shells can be quickly assembled into experiment-ready cubes and disassembled to access internal hardware for replacement or modification.

To provide more reliable cooling ability for our YBCO superconductors, Project RAGNAR will be using a cryocooler to replace the dewar of liquid nitrogen during the microgravity flights. The YBCO cube will be placed on the cryocoooler's coldfinger during the high gravity portions of the flight to 'cryo-charge' the superconductor (that is, to remove heat and keep it below its critical temperature). During the microgravity portions of the flight, the YBCO can be housed in a cube the same size as the magnet module to allow for easier experimenter handling.

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FAST 2009

The FAST 2009 project was designed to perform two related experiments. Two CubeSat-scale mockup modules were designed, one for each experiment, and flux pinned to a YBCO superconducter cooled in a dewar of liquid nitrogen capable of safely operating in microgravity. The experimental manuevers were recorded by a high speed motion capture camera and saved for post-flight analysis. The equiptment used in these experiments is shown below.

One cube module, referred to above as the 6DOF cube, was equipped with an array of electromagnets on one face that were used to demonstrate six degree-of-freedom (6DOF) actuation when pinned to the YBCO superconductor. The electromagnets were activated via a BlueTooth connection by one of the flight team members during the experiment.

A second cube module was used to demonstrate the application of flux pinning as a means to form a non-contacting revolute (or hinge) joint. This cube had a large cylindrical magnet extending from one edge of the cube and two electromagnets, one in the center of each adjacent face. This arrangement is shown above as the hinge rotation cube. The cylindrical magnet was pinned to the YBCO superconductors to form the hinge while the electromagnets allowed it to lock in place and reconfigure remotely. See the Experimental Results page for a more detailed demonstration of the experiment.

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