Abstract: In a spacecraft that controls its position and attitude by a plurality of bipropellant thrusters, controlled ejection and vaporization of a single remaining propellant species generates a thrust force to adjust the spacecraft's position and attitude, thereby allowing an extension of the spacecraft's useful life after the other propellant has been exhausted.

Abstract: An apparatus is disclosed for sensing rotational or angular position of a shaft. The apparatus incorporates two light transmission paths, each having a separate photodetector providing an electrical signal in response to the intensity of received light. The electrical signals from the photodetectors are differentially processed to obtain a signal representative of rotational position. Devices are provided in each of the light transmission paths to vary the intensity of light transmitted in the path, and these devices are mechanically coupled to the shaft so that the variations in the respective light paths are opposite. The differentially processed photodetector signals are therefore unaffected by the absolute position of the shaft but are responsive only to deviations from a reference position. Furthermore, this differentially processed signal exhibits a higher degree of linearity was heretofore obtainable. Various embodiments are disclosed for achieving this opposite variation in the respective light paths.

Abstract: An apparatus is disclosed for sensing rotational or angular position of a shaft. The apparatus incorporates two light transmission paths, each having a separate photodetector providing an electrical signal in response to the intensity of received light. The electrical signals from the photodetectors are differentially processed to obtain a signal representative of rotational position. Devices are provided in each of the light transmission paths to vary the intensity of light transmitted in the path, and these devices are mechanically coupled to the shaft so that the variations in the respective light paths are opposite. The differentially processed photodetector signals are therefore unaffected by the absolute position of the shaft but are responsive only to deviations from a reference position. Futhermore, this differentially processed signal exhibits a higher degree of linearity was heretofor obtainable. Various embodiments are disclosed for achieving this opposite variation in the respective light paths.

Abstract: A jet tab steerable missile having a plurality of tab-shaped elements rotatably mounted on the rear portion of the missile adjacent the nozzle. The tab-shaped elements are capable of 360.degree. rotary movement from a thrust vector control position into the air stream. In so doing the tab-shaped elements will provide post "burn out" side force generation, and therefore, extend range control of the missile.