Engineering topics

Schier, J. Alan

Publications and source records attributed to Schier, J. Alan.

6 records

NASA NTRS1991

Fluid-loop reaction system

An improved fluid actuating system for imparting motion to a body such as a spacecraft is disclosed. The fluid actuating system consists of a fluid mass that may be controllably accelerated through at least one fluid path whereby an opposite acceleration is experienced by the spacecraft. For full control of the spacecraft's orientation, the system would include a plurality of fluid paths. The fluid paths may be circular or irregular, and the fluid paths may be located on the interior or exterior of the spacecraft.

Lurie, Boris J.↗

NASA NTRS1990

Liquid-Ring Attitude-Control System For Spacecraft

Angular momentum transferred to liquid flowing in rings of tubing. Proposed fluid-ring actuator used to orient spacecraft. Used instead of rotating inertia wheels. Meets need for pointing system of low mass, low power, and high resolution. Advantage of actuator, rings of tubing routed through existing structures, minimizing required space and mass.

Lurie, Boris J.↗

NASA NTRS1990

Torque sensor having a spoked sensor element support structure

Piezoelectric sensor devices are attached across pairs of circularly arranged spokes arrayed on the periphery of an annular ring. The sensor devices each include a preloaded steel ball mounting arrangement for mounting a piezoelectric sensor element. A first circular interface plate on one side of the sensor structure attaches to alternate one of the spokes, and a circular interface plate on the opposite side of the same diameter as the first interface plate attaches to the remaining spokes.

Lurie, Boris J.↗

NASA NTRS1989

Multiple-Cantilever Torque Sensor

Sensitivity to spurious loads small. High stiffness, high resolution, and ease of fabrication among features of specially designed torque sensor. Device flexible and sensitive to torque about its cylindrical axis and stiff enough to be insensitive to bending about any perpendicular axis. Measures and transmits torque between driving and driven plates.

Lurie, Boris J.↗

NASA NTRS1988

A precision pointing system for space telescope class optical trackers

This paper reports on the results of a study effort whose main objective was to develop a conceptual design for a space based, large-payload (3000 kg) pointing system capable of both rapid slew maneuvers (0.35 rad/sec-squared) and very stable tracking (1 microrad, 1 sigma, each axis). The key features of the resulting solution are: (1) cross elevation over elevation gimbal system, (2) closed cross elevation gimbal ring, (3) graphite-epoxy structure, (4) two-motor reactionless joint torquers, (5) payload mounted vernier reaction wheel, and (6) gyrostabilized model following control system.

Sevaston, George E.↗

NASA NTRS1988

The Mariner Mark II high precision scan actuator - Results of an options trade study covering pointing performance and system-wide impacts

Four actuators considered as candidates to meet the requirements of the Mariner Mark II high-precision scan platform are evaluated with respect to such criteria as the net effect on spacecraft mass, required power, cost, expected pointing performance, operational considerations, and necessary control complexity. A direct drive actuator is found to be the most suitable candidate. It is noted that for missions where reactionless actuation results in a lower spacecraft mass due to propellant savings, the option of using a platform mounted or spacecraft mounted reaction wheel for platform momentum compensation and spacecraft attitude control is attractive.

Schier, J. Alan↗