A six-degrees-of-freedom (DOF) testbed was developed for evaluating microgravity and low-gravity proximity and contact operations, e.g. in the vicinity of a near Earth orbit, for simulation of proximity operations for a human mission to an asteroid. This is accomplished using an “inverted Stewart platform” where the vehicle under test — in this case, the ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) — is suspended by six computer-controlled cable winches so that it can be maneuvered in all six degrees of freedom. Position feedback is provided by both the encoders at the winch motor, and a motion capture system installed on the testbed structural frame. The payload is attached to the work platform at the end of the six cables.

This work was done by Brian H. Wilcox, Matthew A. Frost, John M. Leichty, Christopher McQuin, and Jack C. Morrison of Caltech for NASA’s Jet Propulsion Laboratory. For more information, contact This email address is being protected from spambots. You need JavaScript enabled to view it.. NPO-48421

NASA Tech Briefs Magazine

This article first appeared in the April, 2014 issue of NASA Tech Briefs Magazine.

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