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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 73 records · Page 4

All sources NASA NTRS DOE OSTI

NASA NTRS1991

The SIR-C/X-SAR synthetic aperture radar system

SIR-C/X-SAR, a three-frequency radar to be flown on the Space Shuttle in September 1993, is described. The SIR-C system is a two-frequency radar operating at 1250 MHz (L-band) and 5300 MHz (C-band), and is designed to get four-polarization radar imagery at multiple surface angles. The X-SAR system is an X-band imaging radar operating at 9600 MHz. The discussion covers the mission concept; system design; hardware; RF electronics; digital electronics; command, timing, and telemetry; and testing.

Jordan, Rolando L.↗

NASA NTRS1989

General-Purpose Electronic System Tests Aircraft

Versatile digital equipment supports research, development, and maintenance. Extended aircraft interrogation and display system is general-purpose assembly of digital electronic equipment on ground for testing of digital electronic systems on advanced aircraft. Many advanced features, including multiple 16-bit microprocessors, pipeline data-flow architecture, advanced operating system, and resident software-development tools. Basic collection of software includes program for handling many types of data and for displays in various formats. User easily extends basic software library. Hardware and software interfaces to subsystems provided by user designed for flexibility in configuration to meet user's requirements.

Glover, Richard D.↗

NASA NTRS2014

Microscale Digital Vacuum Electronic Gates

Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

Manohara, Harish↗

DOE OSTI2025

The Mu2e Calorimeter

The EM CsI crystals and SiPM readout calorimeter of the Mu2e experiment is fully assembled, with all components completed and tested; the mechanical structure is fully built, with a complete integration and test of all the analog sensors and electronics. The digital electronics is being produced and installed. We summarise the Calorimeter characteristics and the assembly status, as well as the move, installation and commissioning plans of the final disks in the Mu2e hall.

Borrel, L. [Caltech]↗

NASA NTRS1980

Propulsion controls

Increased system requirements and functional integration with the aircraft have placed an increased demand on control system capability and reliability. To provide these at an affordable cost and weight and because of the rapid advances in electronic technology, hydromechanical systems are being phased out in favor of digital electronic systems. The transition is expected to be orderly from electronic trimming of hydromechanical controls to full authority digital electronic control. Future propulsion system controls will be highly reliable full authority digital electronic with selected component and circuit redundancy to provide the required safety and reliability. Redundancy may include a complete backup control of a different technology for single engine applications. The propulsion control will be required to communicate rapidly with the various flight and fire control avionics as part of an integrated control concept.

Harkney, R. D.↗

NASA NTRS1987

AVIRIS onboard data handling and control

The timing and flow of detector and ancillary data for the Airborne Visible/Infrared imaging spectrometer (AVIRIS) are controlled within the instrument by its digital electronics assembly. In addition to providing detector and signal chain timing, the digital electronics receives, formats, and rate-buffers digitized science data; collects and formats ancillary (calibration and engineering) data; and merges both into a single tape record. Overall AVIRIS data handling is effected by a combination of dedicated digital electronics to control instrument timing, image data flow, and data rate buffering and a microcomputer programmed to handle real-time control of instrument mechanisms and the coordinated preparation of ancillary data.

Steinkraus, Ronald E.↗

NASA NTRS1988

AVIRIS onboard data handling and control

The timing and flow of detector and ancillary data for the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are controlled within the instrument by its digital electronics assembly. In addition to providing detector and signal chain timing, the digital electronics receives, formats, and rate-buffers digitized science data; collects and formats ancillary (calibration and engineering) data; and merges both into a single tape record. Overall AVIRIS data handling is effected by a combination of dedicated digital electronics to control instrument timing, image data flow, and data rate buffering and a microcomputer programmed to handle real-time control of instrument mechanisms and the coordinated preparation of ancillary data.

Steinkraus, Ronald E.↗

NASA NTRS2010

Carbon Nanotube-Based Digital Vacuum Electronics and Miniature Instrumentation for Space Exploration

JPL has developed high performance cold cathodes using arrays of carbon nanotube bundles that produce > 15 A/sq cm at applied fields of 5 to 8 V/micron without any beam focusing. They have exhibited robust operation in poor vacuums of 10(exp -6) to 10(exp -4) Torr- a typically achievable range inside hermetically sealed microcavities. Using these CNT cathodes JPL has developed miniature X-ray tubes capable of delivering sufficient photon flux at acceleration voltages of <20kV to perform definitive mineralogy on planetary surfaces; mass ionizers that offer two orders of magnitude power savings, and S/N ratio better by a factor of five over conventional ionizers. JPL has also developed a new class of programmable logic gates using CNT vacuum electronics potentially for Venus in situ missions and defense applications. These digital vacuum electronic devices are inherently high-temperature tolerant and radiation insensitive. Device design, fabrication and DC switching operation at temperatures up to 700 C are presented in this paper.

Carbon Nanotube↗

NASA NTRS1990

Propulsion system-flight control integration-flight evaluation and technology transition

Integration of propulsion and flight control systems and their optimization offering significant performance improvement are assessed. In particular, research programs conducted by NASA on flight control systems and propulsion system-flight control interactions on the YF-12 and F-15 aircraft are addressed; these programs have demonstrated increased thrust, reduced fuel consumption, increased engine life, and improved aircraft performance. Focus is placed on altitude control, speed-Mach control, integrated controller design, as well as flight control systems and digital electronic engine control. A highly integrated digital electronic control program is analyzed and compared with a performance seeking control program. It is shown that the flight evaluation and demonstration of these technologies have been a key part in the transition of the concepts to production and operational use on a timely basis.

Burcham, Frank W., Jr.↗

NASA NTRS1995

Performance seeking control program overview

The Performance Seeking Control (PSC) program evolved from a series of integrated propulsion-flight control research programs flown at NASA Dryden Flight Research Center (DFRC) on an F-15. The first of these was the Digital Electronic Engine Control (DEEC) program and provided digital engine controls suitable for integration. The DEEC and digital electronic flight control system of the NASA F-15 were ideally suited for integrated controls research. The Advanced Engine Control System (ADECS) program proved that integrated engine and aircraft control could improve overall system performance. The objective of the PSC program was to advance the technology for a fully integrated propulsion flight control system. Whereas ADECS provided single variable control for an average engine, PSC controlled multiple propulsion system variables while adapting to the measured engine performance. PSC was developed as a model-based, adaptive control algorithm and included four optimization modes: minimum fuel flow at constant thrust, minimum turbine temperature at constant thrust, maximum thrust, and minimum thrust. Subsonic and supersonic flight testing were conducted at NASA Dryden covering the four PSC optimization modes and over the full throttle range. Flight testing of the PSC algorithm, conducted in a series of five flight test phases, has been concluded at NASA Dryden covering all four of the PSC optimization modes. Over a three year period and five flight test phases 72 research flights were conducted. The primary objective of flight testing was to exercise each PSC optimization mode and quantify the resulting performance improvements.

Orme, John S.↗

NASA NTRS1987

The value of early flight evaluation of propulsion concepts using the NASA F-15 research airplane

The value of early flight evaluation of propulsion and propulsion control concepts was demonstrated on the NASA F-15 airplane in programs such as highly integrated digital electronic control (HIDEC), the F100 engine model derivative (EMD), and digital electronic engine control (DEEC). (In each case, the value of flight demonstration was conclusively demonstrated). This paper described these programs, and discusses the results that were not expected, based on ground test or analytical prediction. The role of flight demonstration in facilitating transfer of technology from the laboratory to operational airplanes is discussed.

Burcham, Frank W., Jr.↗

NASA NTRS1987

The value of early flight evaluation of propulsion concepts using the NASA F-15 research airplane

The value of early flight evaluation of propulsion and propulsion control concepts was demonstrated on the NASA F-15 airplane in programs such as highly integrated digital electronic control (HIDEC), the F100 engine model derivative (EMD), and digital electronic engine control (DEEC). (In each case, the value of flight demonstration was conclusively demonstrated.) This paper describes these programs, and discusses the results that were not expected, based on ground test or analytical prediction. The role of flight demonstration in facilitating transfer of technology from the laboratory to operational airplanes is discussed.

Burcham, Frank W., Jr.↗

NASA NTRS1991

Optical correlator techniques applied to robotic vision

Vision processing is one of the most computationally intensive tasks required of an autonomous robot. The data flow from a single typical imaging sensor is roughly 60 Mbits/sec, which can easily overload current on-board processors. Optical correlator-based processing can be used to perform many of the functions required of a general robotic vision system, such as object recognition, tracking, and orientation determination, and can perform these functions fast enough to keep pace with the incoming sensor data. We describe a hybrid digital electronic/analog optical robotic vision processing system developed at Ames Research Center to test concepts and algorithms for autonomous construction, inspection, and maintenance of space-based habitats. We discuss the system architecture design and implementation, its performance characteristics, and our future plans. In particular, we compare the performance of the system to a more conventional all digital electronic system developed concurrently. The hybrid system consistently outperforms the digital electronic one in both speed and robustness.

Hine, Butler P., III↗

NASA NTRS1977

Quiet Clean Short-haul Experimental Engine (QCSEE) over-the-wing control system design report

A control system incorporating a digital electronic control was designed for the over-the-wing engine. The digital electronic control serves as the primary controlling element for engine fuel flow and core compressor stator position. It also includes data monitoring capability, a unique failure indication and corrective action feature, and optional provisions for operating with a new type of servovalve designed to operate in response to a digital-type signal and to fail with its output device hydraulically locked into position.

Source record↗

NASA NTRS1979

LED instrument approach instruction display

A display employing light emitting diodes (LED's) was developed to demonstrate the feasibility of such displays for presenting landing and navigation information to reduce the workload of general aviation pilots during IFR flight. The display consists of a paper tape reader, digital memory, control electronics, digital latches, and LED alphanumeric displays. A presentable digital countdown clock-timer is included as part of the system to provide a convenient means of monitoring time intervals for precise flight navigation. The system is a limited capability prototype assembled to test pilot reaction to such a device under simulated IFR operation. Pilot opinion indicates that the display is helpful in reducing the IFR pilots workload when used with a runway approach plate. However, the development of a compact, low power second generation display was recommended which could present several instructions simultaneously and provide information update capability. A microprocessor-based display could fulfill these requirements.

Meredith, B. D.↗

NASA NTRS1984

Control technology for future aircraft propulsion systems

The need for a more sophisticated engine control system is discussed. The improvements in better thrust-to-weight ratios demand the manipulation of more control inputs. New technological solutions to the engine control problem are practiced. The digital electronic engine control (DEEC) system is a step in the evolution to digital electronic engine control. Technology issues are addressed to ensure a growth in confidence in sophisticated electronic controls for aircraft turbine engines. The need of a control system architecture which permits propulsion controls to be functionally integrated with other aircraft systems is established. Areas of technology studied include: (1) control design methodology; (2) improved modeling and simulation methods; and (3) implementation technologies. Objectives, results and future thrusts are summarized.

Zeller, J. R.↗

NASA NTRS1994

Hot gas ingestion effects on fuel control surge recovery and AH-1 rotor drive train torque spikes

This report summarizes the work accomplished through computer simulation to understand the impact of the hydromechanical turbine assembly (TA) fuel control on rocket gas ingestion induced engine surges on the AH-1 (Cobra) helicopter. These surges excite the lightly damped torsional modes of the Cobra rotor drive train and can cause overtorqueing of the tail rotor shaft. The simulation studies show that the hydromechanical TA control has a negligible effect on drive train resonances because its response is sufficiently attenuated at the resonant frequencies. However, a digital electronic control working through the TA control's separate, emergency fuel metering system has been identified as a solution to the overtorqueing problem. State-of-the-art software within the electronic control can provide active damping of the rotor drive train to eliminate excessive torque spikes due to any disturbances including engine surges and aggressive helicopter maneuvers. Modifications to the existing TA hydromechanical control are relatively minor, and existing engine sensors can be utilized by the electronic control. Therefore, it is concluded that the combination of full authority digital electronic control (FADEC) with hydromechanical backup using the existing TA control enhances flight safety, improves helicopter performance, reduces pilot workload, and provides a substantial payback for very little investment.

Tokarski, Frank↗

NASA NTRS2007

Performance of the Three-Dimensional Track Imager (3-DTI) for Gamma-Ray Telescopes

We have been developing a gas time projection chamber for the imaging of gamma-rays between 0.3 - 50 MeV, the Three-Dimensional Track Imager (3DTI). The detector is being designed for use on satellite experiments for the imaging of astrophysical gamma-ray sources. Electrons produced by pair production or Compton scattering ionize the gas and these ionization electrons are detected by the cross-strip micro-well detector at the bottom of the chamber. Discrete component of front end electronics and time digitization electronics have been developed. We will present results of prototype microwell detector and laboratory set-up in various gas mixtures.

Son, Seunghee↗