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Bartman, R.

Publications and source records attributed to Bartman, R..

15 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Covering a sphere with retroreflectors

This paper discusses how retroreflectors can be placed on the orbiting sample canister with the objective of maximizing returned light from a scanning laser system. The retroreflectors are vital for acquisition of the sample canister during the terminal rendezvous phase of the capture.

retroreflectors simulation Rayleigh-Sommerfield di↗
NASA NTRS1996

Silicon Bulk Micromachined Vibratory Gyroscope

This paper reports on design, modeling, fabrication, and characterization of a novel silicon bulk micromachined vibratory rate gyroscope designed for microspacecraft applications. The new microgyroscope consists of a silicon four leaf cloverstructure with a post attached to the center.

gyroscope microgyroscope↗
NASA NTRS1994

Advanced Mico-Gn&C Technology for Low-Cost Planetary

The new NASA paradigm calls for more frequent, low-cost, small spacecraft missions capable of returning high-value planetary science. This challenge also extends to the rapid insertion of advanced technologies across all spacecraft subsystems as an enabling tool for building these highly capable miniaturized science platforms in the spirit of.

planetary spacecraft tracking gravity-field mappin↗
NASA NTRS1993

Control of micromachined deformable mirrors

A micromachined deformable mirror with pixelated electrostatic actuators is proposed. The paper begins with a physical description of the proposed mirror. Then a mathematical model in the form of a nonlinear partial differential equation describing the mirror surface deformations is derived. This model is used to derive the required voltages for the actuators to achieve a specified static deformation of the mirror surface. This is followed by the derivation of a static nonlinear feedback controller for achieving noninteracting actuation. Then the structure for a complete control system for wavefront correction is proposed. The paper concludes with a discussion of the physical implementation of the proposed control system.

Agronin, M. L.↗
NASA NTRS1992

Control of Micromachined Deformable Mirrors

A micromachined deformable mirror with pixelated electrostatic actuators is proposed. The paper begins with a physical description of the proposed mirror. Then, a mathematical model in the form of a nonlinear partial differential equation describing the mirror surface deformations is derived. This model is used to derive the required voltages for the actuators to achieve a specified static deformation of the mirror surface. This is followed by the derivation of a static nonlinear feedback controller for achieving noninteracting actuation. Then, the structure for a complete control system for wavefront correction is proposed. The paper concludes with a discussion of the physical implementation of the proposed control system.

mirrors↗
NASA NTRS1992

Fiber optic rotation sensor for long lifetime space missions

The present F-O rotation sensors (FORS) are all-solid state devices for measuring rotations and rotation rates in inertial space that may reach the 0.003 deg/hr (1-sigma) accuracies required for NASA's Saturn-orbiting Cassini mission. Attention is presently given to the mission, inertial reference unit, and FORS instrument optoelectronic component requirements envisioned for such spacecraft applications.

Dorsky, L.↗
NASA NTRS1988

A figure control sensor for the Large Deployable Reflector (LDR)

A sensing and control system is required to maintain high optical figure quality in a segmented reflector. Upon detecting a deviation of the segmented surface from its ideal form, the system drives segment mounted actuators to realign the individual segments and thereby return the surface to its intended figure. When the reflector is in use, a set of figure sensors will determine positions of a number of points on the back surface of each of the reflector's segments, each sensor being assigned to a single point. By measuring the positional deviations of these points from previously established nominal values, the figure sensors provide the control system with the information required to maintain the reflector's optical figure. The optical lever, multiple wavelength interferometer, and electronic capacitive sensor, the most promising technologies for the development of the figure sensor, are illustrated. It is concluded that to select a particular implementation of the figure sensors, performance requirement will be refined and relevant technologies investigated further.

Bartman, R.↗