Further analysis of EVA self-rescue data

Abstract

A means for rescuing a stranded extravehicular activity (EVA) astronaut is necessary to ensure safe space station operations. One promising device is a hand-held thruster similar to the Hand-Held Maneuvering Unit (HHMU) from the Gemini and Skylab programs. A study was performed in the Virtual Interactive Environment Workstation (VIEW) at NASA Ames Research Center. Three Initial (Separation) Velocities (0.5, 1.0, and 1.5 m/s) were crossed with five Initial spin velocities (0, +/- 0.1, +/- 0.3) to yield 15 different trials. An Attitude Hold system was also modeled, which, when combined with the 15 combinations of separation and spin velocity, provided 30 distinct trails. Recent examinations of the data reveal that Initial (Separation) Velocity and Initial Spin Velocity each produced main effects and combined to produce an interaction effect on Solution Time. Solution Time increased with Initial Velocity and absolute Initial Spin Velocity. Final Roll Angle also increased Initial Spin Velocity. Attitude Hole Fuel increased with absolute Initial Spin Velocity. Interaction effects revealed that main effects were less pronounced at the lowest Initial Velocity level.