Feasibility of a Tractor Type Self-Maneuvering Unit

摘要

A small, unstablized, tractor type, self-maneuvering unit (SMU) is not considered a satisfactory vehicle for extravehicular travel in space. A pendulum analogy of flight does not prove a satisfactory method of analyzing the space flight characteristics of an unstablized system because of the pilots lack of a good reference system and thrust direction indicator. A space flight simulator study reveals that using pitching and yawing thrust to control the main thrust vector of a stablized SMU, the rendezvous with a t target over distances up to five hundred feet is a relatively simple maneuver. No reverse thrust is necessary to reduce terminal velocity because of the small velocity build-up in flight. However, when the conditions of offcenter thrust are simulated by providing a constant roll rate the percentage of hits on the target is reduced from a mean value of 90% to 17%; moreover, the terminal velocity increases to the point where retro-thrust is needed to provide a safe landing. The tractor type SMU is a very risky method of transportation which requires a very skilled operator to obtain even minimum success. (Author)