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Results for “Determination and Control”

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.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Results of wind tunnel tests at Mach 5 on the .004 scale model 2A configuration space shuttle to determine proximity effects and orbiter control effectiveness during orbiter/external tank abort separation (IAG)

Results from tests in the NASA/MSFC Trisonic Wind Tunnel on 0.004-Scale Orbiter and External Tank Force Models in Close Proximity (RTLS Abort Separation Conditions) are presented. The primary test objectives were to obtain data concerning proximity effects on the aerodynamic forces and moments experienced by Vehicle 2A Configuration Shuttle Orbiter and External Tank during an abort separation (Return to Launch Site) at a Mach number of 5. Additionally, data on orbiter control effectiveness during such an abort was obtained. Proximity effects were investigated for relative angles of incidence from minus 5 deg to plus 10 deg of the orbiter FRL with respect to the external tank centerline over a range of vertical and longitudinal displacements from the mated position to 2.5 tank diameters below and 3 tank diameters aft of the mated position.

Garton, W. P.↗
NASA NTRS1974

Space Trajectory Error Analysis Program (STEAP) for halo orbit missions. Volume 1: Analytic and user's manual

Development, test, conversion, and documentation of computer software for the mission analysis of missions to halo orbits about libration points in the earth-sun system is reported. The software consisting of two programs called NOMNAL and ERRAN is part of the Space Trajectories Error Analysis Programs (STEAP). The program NOMNAL targets a transfer trajectory from Earth on a given launch date to a specified halo orbit on a required arrival date. Either impulsive or finite thrust insertion maneuvers into halo orbit are permitted by the program. The transfer trajectory is consistent with a realistic launch profile input by the user. The second program ERRAN conducts error analyses of the targeted transfer trajectory. Measurements including range, doppler, star-planet angles, and apparent planet diameter are processed in a Kalman-Schmidt filter to determine the trajectory knowledge uncertainty. Execution errors at injection, midcourse correction and orbit insertion maneuvers are analyzed along with the navigation uncertainty to determine trajectory control uncertainties and fuel-sizing requirements. The program is also capable of generalized covariance analyses.

Byrnes, D. V.↗
NASA NTRS1974

Pressure activated stability-bypass-control valves to increase the stable airflow range of a Mach 2.5 inlet with 40 percent internal contraction

The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. The inlet stable airflow range provided by various stability-bypass entrance configurations in alternate combination with several stability-bypass exit controls was determined for both steady-state conditions and internal transient pulses. Transient results were also obtained for the inlet with a choke point at the diffuser exit. Instart angles of attack were determined for the various stability-bypass entrance configurations. The response of the inlet-coldpipe system to internal and external oscillating disturbances was determined. Poppet valves at the stability-bypass exit provided an inlet stable airflow range of 28 percent or greater at all static and transient conditions.

Mitchell, G. A.↗
NASA NTRS1976

HEAO attitude control subsystem - A multimode/multimission design

The initial three satellites in the High Energy Astronomy Observatory (HEAO) series are in the final development stages with the first launch to be in April 1977. The overall program design concept stressed cost reduction through use of hardware standardization for the three configurations and missions. The Attitude Control and Determination Subsystem (ACDS) developed for HEAO was able to achieve significant design commonality in both hardware and software in an implementation which satisfied the performance requirements of the different missions. The ACDS thus provides an example of a multimode/multimission design which should soon be operational.

Hoffman, D. P.↗
NASA NTRS1975

NASA Office of Aeronautical and Space Technology Summer Workshop. Volume 6: Structures and dynamics panel

Structural requirements for future space missions were defined in relation to technology needs and payloads. Specific areas examined include: large area space structures (antennas, solar array structures, and platforms); a long, slender structure or boom used to support large objects from the shuttle or hold two bodies apart in space; and advanced composite structures for cost effective weight reductions. Other topics discussed include: minimum gage concepts, high temperature components, load and response determination and control, and reliability and life prediction.

Source record↗
NASA NTRS1976

Flight-test experience of a helicopter encountering an airplane trailing vortex

This paper presents results of a flight-test experiment of a UH-1H helicopter encountering the vortex wake of a C-54 airplane. The helicopter was instrumented to record the pilot control inputs, determine the upset experience, and measure critical loads within the rotor system. During the flight-test program 132 penetrations of the vortex wake were made by the helicopter at separation distances from 3/8 to 6-1/2 nautical miles. Test results indicated that the helicopter upsets and the vortex induced blade loads experienced were minimal and well within safe limits. The upsets were very mild when compared to a typical response of a small airplane to the vortex wake of the C-54 airplane.

Dunham, R. E., Jr.↗
NASA NTRS1977

Biorhythms and space experiments with nonhuman primates

Man's response to exposure to spaceflight and weightlessness is expressed in physiological adjustments which involve his health and ability to function. The amplitude and periodicity of fluctuations in biological processes affect various functions and responses to provocative stimuli. Primates and other species are subjected to tests to determine the consequences of an altered biorhythm on work and performance, emotional stability, biomedical evaluation in space, the ability to cope with the unexpected, and susceptibility to infection, toxicity, radiation, drugs, and stress. Factors in the environment or operational setup which can change the physiological baseline must be determined and controlled.

Winget, C. M.↗
NASA NTRS1978

Advanced aerodynamics and active controls for a next generation transport

In aerodynamics, the use of new and flexible tools for the design of supercritical wings is discussed. Trends in the design and performance of highlift devices are outlined. In the field of active controls, the determination of suitable configurations with regard to flying qualities is described, particularly related to results from a piloted simulation.

Taylor, A. B.↗
NASA NTRS1977

The Viking Radio Science Investigations

The Viking radio science investigations utilize data from the radio tracking and communications systems of the orbiters and landers. The primary areas of research are: (1) dynamical, surface, and internal properties of Mars, (2) atmospheric and ionospheric properties of Mars, and (3) solar system properties. The instrumentation and facilities used are those required for trajectory and orbit determination, spacecraft control, and data transmission. The X-band downlink on the orbiters is also used for communications experiments and for the improvement of radio science capabilities.

Michael, W. H., Jr.↗
NASA NTRS1978

The High Energy Astronomy Observatory X-ray Telescope

The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

Miller, R.↗
NASA NTRS1977

Navigation of the 1982 Jupiter Orbiter Probe mission

A new NASA interplanetary flight project, called Jupiter Orbiter Probe (JOP), has been recently approved by Congress. JOP involves a dual mission intended to explore the planet Jupiter and its environment with an atmospheric probe and a planetary orbiter spacecraft. The probe and orbiter vehicles are to be launched in tandem as a single spacecraft during the time from December 1981 to January 1982. The spacecraft will arrive at Jupiter at the earliest on November 14, 1984. Navigating the JOP spacecraft will be a critical task for the JOP mission. Attention is given to aspects of probe and orbiter delivery, Jupiter orbit insertion and perijove raise, the Satellite Tour, navigation development and the navigation system, the probe delivery, example orbits, velocity perturbation and correction, orbit determination characteristics, orbit determination and control profile, and the correction velocity requirements.

Rourke, K. H.↗
NASA NTRS1978

HEAO attitude reference design

The paper deals with the precision onboard attitude reference implemented as part of the attitude control and determination subsystem for the three High Energy Astronomy Observatories (HEAO-A, HEAO-B, and HEAO-C) in the HEAO scientific spacecraft program. The first observatory (HEAO-A, designated HEAO-1 when in orbit) was launched successfully into near-earth orbit on August 12, 1977. The HEAO attitude reference, analysis techniques for performance prediction, and flight results from the HEAO-1 observatory during its first months of operation. The HEAO-B design is specifically described and analyzed in terms of gyro processing, kinematic integration, ground update algorithm, and star tracker update algorithm. Attitude reference performance estimates are also discussed. It is shown that the orbital performance of the attitude reference correlates very well with the developmental predictions, thereby validating the analytical techniques used during the development. This validation provides a firm basis from which to extrapolate to other applications and related design concepts.

Hoffman, D. P.↗
NASA NTRS1979

Satellite interferometer as an advanced navigation/communication system

An orthogonal system of interferometry baselines aboard a geostationary satellite is proposed to be used for navigation, surveillance, and traffic control. Position determination is based on the relationship between the measured phase differences, the known and unknown transmitter locations, and other systematic error model parameters using a generalized least-squares estimation procedure. It is shown that position accuracy is critically dependent on the baseline length and on the magnitude of the random component of the measuring errors. Several trade-offs with respect to the system accuracies, the number of users, data rates, hardware costs, etc., are examined. Simultaneous use of the same channels for navigation and data transfer is found feasible and five candidate or 'strawman' interferometer system proposals are presented. It is concluded that the system's performance is excellent in comparison with present or planned systems, and that it is viable in meeting potential user's requirements.

Gopalapillai, G. S.↗
NASA NTRS1980

Detecting surface faults on solar mirrors

Two quality control tests determine reflectivity and curvature faults of concave solar mirrors. Curvature defects in solar mirrors are easily revealed by photographing mirror surface. Calibrated aperture placed in front of camera lens admits rays reflecting only from acceptable areas of mirror, blocking out diverging rays reflected from defective areas. Defects can pinpoint problems that may exist in production. Same photograph can be obtained using calibrated disk instead of aperture, except that, this time, only defective areas would be exposed.

Argoud, M. J.↗
NASA NTRS1979

An improved Woodward's panel method for calculating leading-edge and side-edge suction forces at subsonic and supersonic speeds

Woodward's panel method for subsonic and supersonic flow was improved by employing control points determined by exactly matching two-dimensional pressure at a finite number of points. The results show great improvement in the predicted pressure distribution of a flapped airfoil. With the paneling scheme of cosine law in both chordwise and spanwise directions, the method is shown to accurately predict leading edge and side edge suction forces of various configurations in subsonic and supersonic flow.

Lan, C. E.↗
NASA NTRS1979

Flight Technology Improvement

Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems.

Source record↗
NASA NTRS1980

Satellite Power Systems (SPS) concept definition study. Volume 5: Special emphasis studies

Satellite configurations based on the Satellite Power System baseline requirements were analyzed and a preferred concept selected. A satellite construction base was defined, precursor operations incident to establishment of orbital support facilities identified, and the satellite construction sequence and procedures developed. Rectenna construction requirement were also addressed. Mass flow to orbit requirements were revised and traffic models established based on construction of 60 instead of 120 satellites. Analyses were conducted to determine satellite control, resources, manufacturing, and propellant requirements. The impact of the laser beam used for space-to-Earth power transmission upon the intervening atmosphere was examined as well as the inverse effect. The significant space environments and their effects on spacecraft components were investigated to define the design and operational limits imposed by the environments on an orbit transfer vehicle. The results show that LEO altitude 300 nmi and transfer orbit duration 6 months are preferrable.

Hanley, G. M.↗