NASA - National Aeronautics and Space Administration

This electro-mechanical device provides torque and/or orientation control for robotic astronaut assistants in manned space vehicles and small unmanned spacecraft.

Background

Capitalizing on our broad and integrated skill sets of design, analysis, fabrication, testing, and project management in Mechanical, Electronic, and Controls Engineering, NASA Ames’ Project Development Division has produced two generations of small advanced reaction wheels for use in robotic astronaut assistants and small spacecraft. Our expertise in mechanical and electronic CAD, finite element analysis, computer aided controls design/simulation, rapid prototyping, testing, and project management are ready to be harnessed to produce the next, further miniaturized generation of these devices and other space technology designs.

Image right: Miniature reaction wheels are extremely energy efficient.

These reaction wheels have been developed for the Personal Satellite Assistant (PSA), a variety of self-propelled robotic assistants intended to assist astronauts both inside and outside of manned space vehicles for tasks such as inspection, monitoring, repair, and communication. The PSA, developed at NASA Ames, and the JSC AerCam are two examples of such robots presently being developed for inside and outside tasks, respectively. These concepts are likely to be just the beginning of a broad class of miniature robots.

Miniature reaction wheels can be used to rotate and orient the pitch, roll, and yaw of these types of robots with high energy efficiency and precise control. A reaction wheel is basically a flywheel mounted on a central bearing, which is given angular acceleration by the torque of an integrated motor. The resulting counter torque causes the body to which the reaction wheel is attached to rotate in the opposite direction. Not only is the energy expended for this task extremely efficient, but also much of the energy can be recouped regeneratively, if desired.