LATERAL RANGE CONTROL BY BANKING DURING INITIAL PHASES OF SUPERCIRCULAR REENTRIES
Lateral range control by banking during initial phases of supercircular reentries
BANKING↗
SEARCH · Engineering Papers
Results for “phase 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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Study of an Automatic System for Control of the Terminal Phase of Satellite Rendezvous
An analytical and simulation study was conducted of an automatic system to control the terminal phase of rendezvous between two space vehicles. The system employs switching and thrust orientation criteria based upon relative-motion parameters first to establish a collision course and then to reduce the range and range rate to zero simultaneously. Techniques are developed for employing either modulated thrust or on-off thrust at a constant level. Results of the study indicate that the automatic system can effectively control rendezvous over a wide range of initial conditions and can utilize the available fuel in a very efficient manner.
Lineberry, Edgar C., Jr.↗
Modulation-doping a correlated electron insulator
Abstract Correlated electron materials (CEMs) host a rich variety of condensed matter phases. Vanadium dioxide (VO 2 ) is a prototypical CEM with a temperature-dependent metal-to-insulator (MIT) transition with a concomitant crystal symmetry change. External control of MIT in VO 2 —especially without inducing structural changes—has been a long-standing challenge. In this work, we design and synthesize modulation-doped VO 2 -based thin film heterostructures that closely emulate a textbook example of filling control in a correlated electron insulator. Using a combination of charge transport, hard X-ray photoelectron spectroscopy, and structural characterization, we show that the insulating state can be doped to achieve carrier densities greater than 5 × 10 21 cm −3 without inducing any measurable structural changes. We find that the MIT temperature (T MIT ) continuously decreases with increasing carrier concentration. Remarkably, the insulating state is robust even at doping concentrations as high as ~0.2 e − /vanadium. Finally, our work reveals modulation-doping as a viable method for electronic control of phase transitions in correlated electron oxides with the potential for use in future devices based on electric-field controlled phase transitions.
36 MATERIALS SCIENCE↗
Space Station Freedom Environmental Control and Life Support System (ECLSS) phase 3 simplified integrated test trace contaminant control subsystem performance
Space Station Freedom environmental control and life support system testing has been conducted at Marshall Space Flight Center since 1986. The phase 3 simplified integrated test (SIT) conducted from July 30, 1989, through August 11, 1989, tested an integrated air revitalization system. During this test, the trace contaminant control subsystem (TCCS) was directly integrated with the bleed stream from the carbon dioxide reduction subsystem. The TCCS performed as expected with minor anomalies. The test set the basis for further characterizing the TCCS performance as part of advance air revitalization system configurations.
Perry, J. L.↗
Antenna and Flight Control Software for Conformal Phased Array Antenna Design (CPAAD)
The National Aeronautics and Space Administration (NASA) is developing lightweight conformal phased array antenna designs (CPAAD) for beyond line of sight communications [1]. The CPAAD system is developed to address reliable and affordable autonomous next generation aviation systems. The technology takes advantage of newly assigned provisional Ku-bands for UAVs. The antenna design is unique to avoid interference with the ground and the unconventional substrate reduces weight. The surface mounted conformal design allows for reduced drag during flight. The software developed for the CPAAD system operates the antenna hardware and provides a graphic user interface (GUI) for ground testing and flight operations.
phased array antenna control software↗
Microwave microelectronic techniques applied to phase shifters and other control devices Final report, 29 May - 29 Nov. 1968
Microwave microelectronic techniques applied to phase shifters and other control devices
Robinson, G. H.↗
Four quadrant control circuit for a brushless three-phase dc motor
A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.
Nola, Frank J.↗
Phase Detector for Power-Factor Controller
Positive feedback assures reliable switching. Three Phase Power Factor Controller includes three phase detectors, each produces rectangular waves of duration approximately equal to lag time between line voltage and motor current.
Nola, F. J.↗
Phase change material for temperature control and material storage
A phase change material comprising a mixture of water and deuterium oxide is described, wherein the mole fraction of deuterium oxide is selected so that the mixture has a selected phase change temperature within a range between 0.degree. C. and 4.degree. C. The mixture is placed in a container and used for passive storage and transport of biomaterials and other temperature sensitive materials. Gels, nucleating agents, freezing point depression materials and colorants may be added to enhance the characteristics of the mixture.
Wessling, Jr., Francis C.↗
A general review and discussion on geodetic control of the moon, phase 1 Final report
Review and bibliography on geodetic control of moon
Mueller, I. V.↗
Optical pathlength control on the JPL Phase B interferometer testbed
Design and implementation of a controller for optical pathlength compensation on a flexible structure is presented. Nanometer level pathlength control is demonstrated in the laboratory. The experimental results are in close agreement with performance predictions.
Spanos, John T.↗
A microchip microcontroller-based transducer controller for non-contact scanning probe microscopy with phase-locked loop, amplitude, and Q control
An inexpensive yet versatile transducer controller for non-contact scanning probe microscopy (SPM) based on a PIC32 microcontroller from Microchip Technology, Inc is described. In addition to feedback control using the amplitude or phase of the signal from the non-contact transducer, the controller includes a phase-locked loop for frequency-shift feedback, as well as fixed-amplitude, quality factor (Q) control, and self-excitation modes. Apart from the input amplifiers, output buffers, and the Q-control circuit, all other functions of the controller are instantiated in software on the microchip, enabling rapid changes in operating parameters if needed. The controller communicates with a host personal computer via a simple serial connection. The controller has been tested with a quartz tuning-fork transducer but can be used with any oscillating non-contact transducer.
47 OTHER INSTRUMENTATION↗
Optical Phased Array Using Guided Resonance with Backside Reflectors
Methods and systems for controlling the phase of electromagnetic waves are disclosed. A device can consist of a guided resonance grating layer, a spacer, and a reflector. A plurality of devices, arranged in a grid pattern, can control the phase of reflected electromagnetic phase, through refractive index control. Carrier injection, temperature control, and optical beams can be applied to control the refractive index.
Horie, Yu↗
Optical Phased Array Using Guided Resonance with Backside Reflectors
Methods and systems for controlling the phase of electromagnetic waves are disclosed. A device can consist of a guided resonance grating layer, a spacer, and a reflector. A plurality of devices, arranged in a grid pattern, can control the phase of reflected electromagnetic phase, through refractive index control. Carrier injection, temperature control, and optical beams can be applied to control the refractive index.
Horie, Yu↗
Spacelab Phase B study environmental control system component handbook
Descriptions are given of candidate components for the Phase B Study of the Spacelab environmental control system. Most of the hardware was defined for the baseline ECS design concept. A low cost design approach was followed, with most of the components being selected from the Apollo and Skylab Programs.
Burns, R. A.↗
Power control for hot gas engines
A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two level gears to provide a phase angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.
Macglashan, W. F.↗
Subsystem trade-off environmental control and life support for orbiter phase B contractor
Environmental control and life support subsystem for space shuttle orbiter
Jasin, J.↗
Variable-Speed, Constant-Frequency Generation Of Power
Feedback of stator power and reactive volt-amperes determines rotor excitation. New method involves control circuit separating rotor excitation into generation of slip frequency and control of amplitude and phase. In control circuit, speed determines slip frequency, while stator power and reactive volt-amperes determine amplitude and phase of rotor current.
Brady, Frank J.↗