Search NASA⌕ Search

SEARCH · Search NASA

Results for “Attitude Control System”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

New thruster configurations for spacecraft attitude control systems

Design characteristics of thruster configurations for spacecraft attitude control systems investigated. A standard six engine approach is developed and used as the basis for comparison of different thruster configurations. These methods include cases of both skewed and non-skewed configurations. Simulation results are used as a basis for comparison, critical thruster design factors being given based on an analysis of the data.

Colburn, B. K.↗
NASA NTRS2018

42: An Open-Source Simulation Tool for Study and Design of Spacecraft Attitude Control Systems

Simulation is an important tool in the analysis and design of spacecraft attitude control systems. The speaker will discuss the simulation tool, called simply 42, that he has developed over the years to support his own work as an engineer in the Attitude Control Systems Engineering Branch at NASA Goddard Space Flight Center. 42 was intended from the outset to be high-fidelity and powerful, but also fast and easy to use. 42 is publicly available as open source since 2014. The speaker will describe some of 42's models and features, and discuss its applicability to studies ranging from early concept studies through the design cycle, integration, and operations. He will outline 42's architecture and share some thoughts on simulation development as a long-term project.

Stoneking, Eric↗
NASA NTRS1974

An elementary magnetic attitude control system

A three-axis closed-loop attitude-control system for earth-observatory momentum-bias spacecraft is proposed. A horizon scanner and magnetometer are employed to measure attitude errors; no yaw sensor is required. Appropriate control signals are generated and used to command variable-strength electromagnets, which interact with the geomagnetic field to reduce observed errors. This system provides for initial acquisition, precession control, nutation damping, and pitch-axis momentum control. All functions are performed autonomously - no ground-station interaction is required. Analytical expressions predicting system response are compared with numerical solutions of the governing equations, and with the results of the application of Floquet Theory.-

Stickler, A. C.↗
NASA NTRS1986

Inflight redesign of the IUE attitude control system

The one- and two-gyro system designs of the International Ultraviolet Explorer (IUE) attitude control system (ACS) are examined. The inertial reference assembly that provides the primary attitude reference for IUE consists of six rate sensors which are single-axis rate integrating gyros. The gyros operate in a pulse rebalanced mode that produces an output pulse for 0.01 arcsec of motion about the input axis. The functions of the fine error sensor, fine sun sensor (FSS), the IUE reaction wheels, the onboard computer, and the hold/slew algorithm are described. The use of the hold/slew algorithm to compute the control voltage for the ACS based on the Kalman filter is studied. A two-gyro system was incorporated into IUE following gyro failure. The procedures for establishing attitude control with the two-gyro design based on the FSS is analyzed. The performance of the two-gyro system is evaluated; it is observed that the pitch and yaw gyro control is 0.24 arcsec and the control is sufficient to permit extended periods of observation.

Femiano, M. D.↗
NASA NTRS1981

Flight performance of SEASAT-1 attitude control system

The paper describes the attitude control flight performance of SEASAT-A, (launched in June 1978), until failure of the power subsystem terminated the mission in Oct. 1978. Information provided by the satellite pertained to surface winds and coastal storm activity, currents and wave heights, ocean topography and temperature. The ACS used three-axis momentum exchange and magnetic momentum containment and was set in a nose-down configuration. Attitude control sensing was via horizon sensors and attitude anomalies, resulting from solar interference with the sensors, is covered in detail. Remedial action was taken by reconfiguring the IR scanners, but failure resulted nevertheless. Recommendations for similar future missions include consideration of the effect of light sources and circuit time constants and scan rates. A block diagram of the ACS is included.

Beach, S. W.↗
NASA NTRS1986

The Spartan attitude control system - Control electronics assembly

The Spartan attitude control system (ACS) represents an evolutionary development of the previous STRAP-5 ACS through the use of state-of-the-art microprocessors and hardware. Despite a gyro rate signal noise problem that caused the early depletion of argon gas, the Spartan 101 experiment was able to collect several hours of data from two targets. Attention is presently given to the ACS sequencer module, sensor interface box, valve driver box, control electronics software, jam tables, and sequencer programs.

Stone, R. W.↗
NASA NTRS1986

Applications software supporting the Spartan Attitude Control System

The native software supporting a single mission for the Spartan Attitude Control System can require up to 40,000 lines of code. Most of this must be rewritten for each mission. Control system engineers use an array of Applications Software Packages residing in ground computers to write each mission's flight software. These Applications Packages are written in the 'C' programming language and run under the UNIX Operating System. This paper discusses each of the Attitude Control Applications Software Packages, and describes the purpose and design of each.

Stone, R. W.↗
NASA NTRS1977

All sky pointing attitude control system

In a strapped-down gyroscope space vehicle attitude control system, a method and apparatus are provided for gyro drift and input axis misalignment error compensation employing a sun and a star tracker and preselected vehicle calibration maneuvers. The outputs of two-axis strapped-down gyroscopes nominally aligned with the optical axis of the sun and star trackers are measured to provide gyro drift calibration, roll, pitch and yaw axis scale factors and values corresponding to the degree of nonorthogonality between the roll axis and the pitch and yaw gyro input axes and the nonorthogonality of the roll and pitch axes relative to the yaw axis. The vehicle is then rolled and yawed through precomputed angles as modified by the calibrated data stored in a digital computer, and acquires a target without recourse to external references.

Lorell, K. R.↗
NASA NTRS1995

Adaptive Attitude Control System For Space Station

Report presents theoretical foundation for attitude control system for proposed Space Station Freedom in orbit around Earth. Intended to maintain space station in torque equilibrium with designated axes of its structure aligned with local vertical, local along-trajectory horizontal, and local across-trajectory horizontal axes, respectively. System required to provide desired combination of control performance and stability in presence of disturbances (e.g., variations in masses of payloads, movements of astronauts and equipment, atmospheric drag, gravitational anomalies, and interactions with docking spacecraft).

Boussalis, Dhemetrios↗