A mathematical model for simulation of the Apollo telescope mount pointing control system
Mathematical model and computer program for simulation of Apollo telescope mount pointing control system
Smith, P. G.↗
SEARCH · Search NASA
Results for “pointing control systems”
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.
An investigation of the fine-pointing control system of a soft-gimbaled orbiting telescope
Computerized simulation of fine pointing control system of soft-gimbaled orbiting telescope
Morrell, F. R.↗
Modeling, designing and simulating a pointing control system for balloon-borne solar experiments
A simplified model of a pointing control system for balloon-borne solar experiments is chosen. Equations of motion for this model are derived and a feedback control law is defined. A digital computer simulation of the system is developed. Simulation results show favorable system response characteristics.
Lightsey, W. D.↗
Hubble Space Telescope pointing control system: Designed for performance and mission operations
The Hubble Space Telescope was designed to be an orbiting astronomical observatory which could be operated in the same manner as ground based observatories. The design drivers for the pointing control system's hardware and software were the requirements of an absolute pointing accuracy of 4.8E-8 radians and pointing stability (jitter) of 3.4E-8 radians. Of comparable importance was the objective of providing a flexible command methodology and structure to enable seven day operational planning employing stored program command and real time command capability. The pointing control system hardware, software, safemode control schemes, ground system monitoring capability, and in-orbit results are reviewed.
Bradley, A.↗
Large Space Telescope (LST) Pointing Control System (PCS) analytical Advanced Technical Development (ATD) program
The large space telescope (LST) pointing control system (PCS) advanced technical development (ATD) program is described. The approach used is to describe the overall PCS development effort, showing how the analytical ATD program elements fit into it. Then the analytical ATD program elements are summarized.
Seltzer, S. M.↗
An overview of the pointing control system for NASA's Space Infra-red Telescope Facility (SIRTF)
This paper discusses the pointing control system for NASA's Space Infra-Red Telescope Facility (SIRTF). After an introduction to the SIRTF mission and telescope, an overview is given of the pointing control hardware, pointing control architecture, pointing requirements and capability, attitude constraints and commanding, attitude observers and required calibrations.
pointing control attitude estimation calibration↗
Design of a precision pointing control system for the space infrared telescope facility
This paper describes the design of a precision pointing control system for the Space Infrared Telescope Facility (SIRTF). Mission requirements and their impact on control system design are discussed along with the original features of the control strategy. Simulation of the total system is described, and the most significant results are presented.
Sridhar, B.↗
Conceptual design of pointing control systems for space station gimballed payloads
A conceptual design of the control system for Payload Pointing Systems (PPS) is developed using classic Proportional-Integral-Derivatives (PID) techniques. The major source of system pointing error is due to the disturbance-rich environment of the space station in the form of gimbal baseplate motions. These baseplate vibrations are characterized using Fast Fourier Transform (FFT) techniques. Both time domain and frequency domain dynamic models are developed to assess control system performance. Three basic methods exist for the improvement of PPS pointing performance: increase control system bandwidth, add Image Motion Compensation, and/or reduce (or change) the baseplate disturbance environment.
Hughes, Robert O.↗
Design and evaluation of an optical fine-pointing control system for telescopes utilizing a digital star sensor
One of the most significant problems associated with the development of large orbiting astronomical telescopes is that of maintaining the very precise pointing accuracy required. A proposed solution to this problem utilizes dual-level pointing control. The primary control system maintains the telescope structure attitude stabilized within the field of view to the desired accuracy. In order to demonstrate the feasibility of optically stabilizing the star images to the desired accuracy a regulating system has been designed and evaluated. The control system utilizes a digital star sensor and an optical star image motion compensator, both of which have been developed for this application. These components have been analyzed mathematically, analytical models have been developed, and hardware has been built and tested.
Ostroff, A. J.↗
The Galileo scan platform pointing control system - A modern control theoretic viewpoint
The current Galileo scan platform pointing control system (SPPCS) is described, and ways in which modern control concepts could serve to enhance it are considered. Of particular interest are: the multi-variable design model and overall control system architecture, command input filtering, feedback compensator and command input design, stability robustness constraint for both continuous time control systems and for sampled data control systems, and digital implementation of the control system. The proposed approach leads to the design of a system that is similar to current Galileo SPPCS configuration, but promises to be more systematic.
Sevaston, G. E.↗
Hubble Space Telescope Pointing Control System design improvement study
As part of the NASA Controls/Structures Integration Program, a study was undertaken to determine if improvements to the performance of the Hubble Space Telescope Pointing Control System could be obtained when advanced control system design techniques were applied using simulation models and telemetry data from the spacecraft. The study was managed through the Marshall Space Flight Center. Four universities and one aerospace company developed controller designs and tested their performance. This paper summarizes the goals and provides an overview of the study.
Bukley, Angelia P.↗
Flight Performance of Skylab Attitude and Pointing Control System
In 1967 a paper at the AIAA Guidance, Control and Flight Dynamics Conference in Huntsville, Ala. presented for the first time the prot)osed SKYLAB Attitude and Pointing Control System (APCS) The system requirements, Apollo Telescope Mount (ATM) configuration, control philosophy, and operational modes were presented and the APCS described. The Initial mission and system design requirements changed during the period of time before the SKYLAB was launched. This paper will review the Initial and final APCS requirements and goals and their relationship. The actual flight mission (and Its alterations during the flight) and known achieved APCS performance will then be presented. SKYLAB was a tremendous success in furthering man's scientific knowledge; but perhaps SKYLAB will be remembered more for the anomalies and the efforts undertaken to solve them. On May 14, 1973, the unmanned SKYLAB Orbital Workshop (OWS) was launched from Cape Kennedy. Serious hardware failures began to occur during ascent through the atmosphere and their spectre continued to haunt both the astronauts and their ground based support team. Nor were these the only surprises affecting the design and operation of the APCS. Mission requirements for pointing to various stellar targets and to nadir for earth resources experiments were added after the hardware was designed. The chance appearance of comet Kohoutek during the SKYLAB operational life-time caused NASA to add comet observation to the mission requirements and to adjust the time when the third crew would man the SKYLAB. The development of new procedures and software for the opportunity to observe this visitor to our solar system is described.
Chubb, W. B.↗
ACCESS Pointing Control System
ACCESS (Actively-Corrected Coronograph for Exoplanet System Studies) was one of four medium-class exoplanet concepts selected for the NASA Astrophysics Strategic Mission Concept Study (ASMCS) program in 2008/2009. The ACCESS study evaluated four major coronograph concepts under a common space observatory. This paper describes the high precision pointing control system (PCS) baselined for this observatory.
space telescope↗
Knowledge-based monitoring of the pointing control system on the Hubble space telescope
A knowledge-based system for the real time monitoring of telemetry data from the Pointing and Control System (PCS) of the Hubble Space Telescope (HST) that enables the retention of design expertise throughout the three decade project lifespan by means other than personnel and documentation is described. The system will monitor performance, vehicle status, success or failure of various maneuvers, and in some cases diagnose problems and recommend corrective actions using a knowledge base built using mission scenarios and the more than 4,500 telemetry monitors from the HST.
Dunham, Larry L.↗
Terrestrial Planet Finder coronagraph pointing control system design and evaluation for flight baseline 1.
The Terrestrial Planet Finder mission will search for Earth-like, extrasolar planets. The Coronagraph architecture option (TPF-C) will use contrast imaging to suppress the bright starlight in order to detect reflected visible light from the planet. To achieve the required contrast ratio stability of 2e-11, the payload pointing stability must be maintained to better than 4 milli-asec (1σ). The passive TPF-C pointing architecture uses a 3-stage control system combined with a 2- stage passive isolation system to achieve the required pointing accuracy. The active pointing stage includes reaction wheels used for coarse pointing of the spacecraft, a position controlled secondary mirror that provides intermediate alignment, and a Fine Guidance Mirror that provides fine steering control.
Dewell, Larry↗
A low cost LST pointing control system
Vigorous efforts to reduce costs, coupled with changes in LST guidelines, took place in the Fall of 1974. These events made a new design of the LST and its Pointing and Attitude Control System possible. The major design changes are summarized as: an annular Support Systems Module; removal of image motion compensation; reaction wheels instead of CMG's; a magnetic torquer system to also perform the emergency and backup functions, eliminating the previously required mass expulsion system. Preliminary analysis indicates the Low Cost LST concept can meet the newly defined requirements and results in a significantly reduced development cost.
Glaese, J. R.↗
Chandra X-Ray Observatory Pointing Control System Performance During Transfer Orbit and Initial On-Orbit Operations
The Chandra X-ray Observatory (CXO, formerly AXAF) is the third of the four NASA great observatories. It was launched from Kennedy Space Flight Center on 23 July 1999 aboard the Space Shuttle Columbia and was successfully inserted in a 330 x 72,000 km orbit by the Inertial Upper Stage (IUS). Through a series of five Integral Propulsion System burns, CXO was placed in a 10,000 x 139,000 km orbit. After initial on-orbit checkout, Chandra's first light images were unveiled to the public on 26 August, 1999. The CXO Pointing Control and Aspect Determination (PCAD) subsystem is designed to perform attitude control and determination functions in support of transfer orbit operations and on-orbit science mission. After a brief description of the PCAD subsystem, the paper highlights the PCAD activities during the transfer orbit and initial on-orbit operations. These activities include: CXO/IUS separation, attitude and gyro bias estimation with earth sensor and sun sensor, attitude control and disturbance torque estimation for delta-v burns, momentum build-up due to gravity gradient and solar pressure, momentum unloading with thrusters, attitude initialization with star measurements, gyro alignment calibration, maneuvering and transition to normal pointing, and PCAD pointing and stability performance.
Quast, Peter↗
Pinhole/coronograph pointing control system integration and noise reduction analysis
The Pinhole Occulter Facility (P/OF) is a Space Shuttle based experiment for the production of solar coronographics and hard X-ray images. The system is basically pinhole camera utilizing a deployable 50-m flexible boom for separating the pinholes and coronograph shields from the recording devices located in the Shuttle bay. At the distal end of the boom from the Shuttle is a 25 kg mask containing pinholes and coronograph shields. At the proximal end the detectors are located and mounted, along with the deployable boom, to the ASPS gimbal pointing system (AGS). The mask must be pointed at the Sun with a high degree of pointing stability and accuracy to align the axes of the detectors with the pinholes and shields. Failure to do so will result in a blurring of the images on the detectors and a loss of resolution. Being a Shuttle based experiment, the system will be subjected to the disturbances of the Shuttle. The worst of these is thruster firing for orbit correction; the Shuttle uses a bang-bang thruster control system to maintain orbit to within preset limits. Other disturbances include man motion, motion induced by other systems, and gravity gradient torques.
Greene, M.↗