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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 55 records · Page 3

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NASA NTRS1987

AKM capture device

In an effort to recover the Westar and Palapa satellites and the considerable investment each represented, NASA and Hughes undertook the Satellite Retrieval Mission. The mechanism used to capture each of the errant satellites was the AKM (Apogee Kick Motor) Capture Device (ACD), also referred to as the Stinger. The ACD had three interface requirements: interface with the Manned Maneuvering Unit (MMU) for transportation to and stabilization of the spacecrafts; interface with each satellite for retrieval; and finally, interface with the Shuttle's Remote Manipulator System (RMS or robot arm) for satellite transport back to the Orbiter's payload bay. The majority of the design requirements were associated with the capture and release of the satellites. In addition to these unique requirements, the general EVA, RMS grapple, and RMS manipulation requirements applied. These requirements included thermal, glare, snag, RMS runaway and crewman safety considerations.

Harwell, William D.↗

NASA NTRS1933

Wind tunnel research comparing lateral control devices, particularly at high angles of attack XI : various floating tip ailerons on both rectangular and tapered wings

Discussed here are a series of systematic tests being conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present tests were made with six different forms of floating tip ailerons of symmetrical section. The tests showed the effect of the various ailerons on the general performance characteristics of the wing, and on the lateral controllability and stability characteristics. In addition, the hinge moments were measured for the most interesting cases. The results are compared with those for a rectangular wing with ordinary ailerons and also with those for a rectangular wing having full-chord floating tip ailerons. Practically all the floating tip ailerons gave satisfactory rolling moments at all angles of attack and at the same time gave no adverse yawing moments of appreciable magnitude. The general performance characteristics with the floating tip ailerons, however, were relatively poor, especially the rate of climb. None of the floating tip ailerons entirely eliminated the auto rotational moments at angles of attack above the stall, but all of them gave lower moments than a plain wing. Some of the floating ailerons fluttered if given sufficiently large deflection, but this could have been eliminated by moving the hinge axis of the ailerons forward. Considering all points including hinge moments, the floating tip ailerons on the wing with 5:1 taper are probably the best of those which were tested.

Weick, Fred E↗

NASA NTRS1933

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack II : slotted ailerons and frise ailerons

Three model wings, two with typical slotted ailerons and one with typical frise ailerons, have been tested as part of a general investigation on lateral control devices with particular reference to their effectiveness at high angles of attack, in the 7 by 10 foot wind tunnel of the National Advisory Committee for Aeronautics. Force tests, free-autorotation tests, and forced-rotation tests were made which show the effect of the various ailerons on the general performance of the wing, on the lateral controllability, and on the lateral stability, in general, rolling control at 20 degree angle of attack to plain ailerons of the same size. The adverse yawing moments obtained with the slotted and frise ailerons were, in most cases, slightly smaller than those obtained with plain ailerons of the same size and deflection. However, this improvement was small as compared to the improvement obtainable by the use of suitable differential movements with any of the ailerons, including the plain.

Weick, Fred E↗

NASA NTRS1933

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack IV : floating tip ailerons on rectangular wings

This report is the fourth of a series on systematic tests conducted which compares lateral control devices with particular reference to their effectiveness at high angles of attack. The present report covers tests with floating tip ailerons on rectangular Clark y wings. Ailerons of two profiles were tested - symmetrical and Clark y, both with adjustable trailing-edge flaps. Each form was tested at three hinge-axis locations, both with and without vertical end plates between the ailerons and the wing proper. The results from these tests are compared with the results from tests on a wing of the same over-all size equipped with average-sized ordinary ailerons.

Weick, Fred E↗

NASA NTRS1935

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack XII : upper-surface ailerons on wings with split flaps

This report covers the twelfth of a series of tests conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made with two sizes of upper-surface ailerons on rectangular Clark Y wing models equipped with full span split flaps. The tests showed the effect of the upper-surface ailerons and of the split flaps on the general performance characteristics of the wings, and on the lateral controllability and stability characteristics. The results are compared with those for plain wings with ordinary ailerons of similar sizes.

Weick, Fred E↗

NASA NTRS1936

Wind-Tunnel Research Comparing Lateral Control Devices Particularly at High Angles of Attack XIII : Auxiliary Airfoils Used as External Ailerons

This is the thirteenth report on a series of systematic tests comparing lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made to determine the most feasible locations for lateral control surfaces mounted externally to a rectangular Clark y wing.

Weick, Fred E↗

NASA NTRS1993

Advances in time-scale algorithms

The term clock is usually used to refer to a device that counts a nearly periodic signal. A group of clocks, called an ensemble, is often used for time keeping in mission critical applications that cannot tolerate loss of time due to the failure of a single clock. The time generated by the ensemble of clocks is called a time scale. The question arises how to combine the times of the individual clocks to form the time scale. One might naively be tempted to suggest the expedient of averaging the times of the individual clocks, but a simple thought experiment demonstrates the inadequacy of this approach. Suppose a time scale is composed of two noiseless clocks having equal and opposite frequencies. The mean time scale has zero frequency. However if either clock fails, the time-scale frequency immediately changes to the frequency of the remaining clock. This performance is generally unacceptable and simple mean time scales are not used. First, previous time-scale developments are reviewed and then some new methods that result in enhanced performance are presented. The historical perspective is based upon several time scales: the AT1 and TA time scales of the National Institute of Standards and Technology (NIST), the A.1(MEAN) time scale of the US Naval observatory (USNO), the TAI time scale of the Bureau International des Poids et Measures (BIPM), and the KAS-1 time scale of the Naval Research laboratory (NRL). The new method was incorporated in the KAS-2 time scale recently developed by Timing Solutions Corporation. The goal is to present time-scale concepts in a nonmathematical form with as few equations as possible. Many other papers and texts discuss the details of the optimal estimation techniques that may be used to implement these concepts.

Stein, S. R.↗

NASA NTRS2010

Suited Occupant Injury Potential During Dynamic Spacecraft Flight Phases

In support of the Constellation Space Suit Element [CSSE], a new space-suit architecture will be created for support of Launch, Entry, Abort, Microgravity Extra- Vehicular Activity [EVA], and post-landing crew operations, safety and, under emergency conditions, survival. The space suit is unique in comparison to previous launch, entry, and abort [LEA] suit architectures in that it utilizes rigid mobility elements in the scye (i.e., shoulder) and the upper arm regions. The suit architecture also utilizes rigid thigh disconnect elements to create a quick disconnect approximately located above the knee. This feature allows commonality of the lower portion of the suit (from the thigh disconnect down), making the lower legs common across two suit configurations. This suit must interface with the Orion vehicle seat subsystem, which includes seat components, lateral supports, and restraints. Due to the unique configuration of spacesuit mobility elements, combined with the need to provide occupant protection during dynamic vehicle events, risks have been identified with potential injury due to the suit characteristics described above. To address the risk concerns, a test series has been developed in coordination with the Injury Biomechanics Research Laboratory [IBRL] to evaluate the likelihood and consequences of these potential issues. Testing includes use of Anthropomorphic Test Devices [ATDs; vernacularly referred to as "crash test dummies"], Post Mortem Human Subjects [PMHS], and representative seat/suit hardware in combination with high linear acceleration events. The ensuing treatment focuses on test purpose and objectives; test hardware, facility, and setup; and preliminary results.

Dub, Mark O.↗

NASA NTRS2017

Proton Testing of nVidia Jetson TX1

Single-Event Effects (SEE) testing was conducted on the nVidia Jetson TX1 System on Chip (SOC); herein referred to as device under test (DUT). Testing was conducted at Massachusetts General Hospitals (MGH) Francis H. Burr Proton Therapy Center on October 16th, 2016 using 200MeV protons. This testing trip was purposed to provide a baseline assessment of the radiation susceptibility of the DUT as no previous testing had been conducted on this component.

Proton testing↗

NASA NTRS2017

Proton Testing of nVidia GTX 1050 GPU

Proton testing↗

NASA NTRS2018

Proton Testing of nVidia GTX 1050 GPU, Part 2

Single-Event Effects (SEE) testing was conducted on the nVidia GTX 1050 Graphics Processor Unit (GPU); herein referred to as device under test (DUT). Testing was conducted at Massachusetts General Hospital's (MGH) Francis H. Burr Proton Therapy Center on April 28th, 2018 using 200-MeV protons. This testing trip was purposed to provide additional radiation susceptibility data from payloads compiled in Q3FY18. While not all radiation-induced errors are critical, the effects on the application need to be considered. More so, failure of the device and an inability to reset itself should be considered detrimental to the application. Radiation effects on electronic components are a significant reliability issue for systems intended for space.

Single-Event Effects (SEE)↗

NASA NTRS2026

Long-Term Evaluation of Landsat 9 Oli Data Product Uniformity at Focal Plane Module-Boundaries Using Earth Scenes

The uniformity performance characteristic in remote sensing data products is a metric that helps evaluate how an image accurately represents radiometric responses to geophysical variability at the Earth’s surface or within the atmosphere. These uniformity attributes are used in Earth remote sensing science applications such as investigating water quality, land-cover/land-use classifications, and crop health assessments. To ensure these applications perform effectively, it is crucial to maintain and regularly assess the uniformity of calibrated remote sensing data products. In the Landsat missions, data from the onboard radiometric reference Solar diffuser device are used as the standard approach to derive the calibration parameters, ensuring the maintenance of both absolute radiance and radiometric uniformity through quarterly updates. This publication presents an alternative approach that leverages Earth scene data to assess the on-orbit uniformity performance of the Landsat 9 (L9) mission. The analysis characterizes uniformity at a specific set of spatial positions (the focal-plane boundary zones) that are intrinsic to the Operational Land Imager (OLI) focal plane design. By employing these Earth data statistics, the article further explores the temporal trends in the radiometric uniformity results. The results shown in this article demonstrate that for pushbroom imaging design systems with staggered sensor chip focal plane architectures, the co-registered pixels, i.e., overlapping measurements of the same ground target viewed by different detectors, offer a self-contained mechanism for assessing product uniformity. Remarkably, this alternative approach achieves a level of radiometric quality comparable to that delivered by a stable, well-characterized onboard Solar diffuser calibration device. The findings demonstrate the potential and capability of such Earth scene statistics in maintaining radiometric uniformity in calibrated data products to better than 1% (1-sigma) throughout the mission’s operational lifetime.

trend↗

NASA NTRS2004

High-Temperature Probe Station Developed to Characterize Microwave Devices Through 500 C

A photograph and a block diagram of the high-temperature probe station are shown. The system consists of the ceramic heater mounted on a NASA shuttle tile insulator, a direct current power supply, a personal-computer-based data acquisition and temperature controller, microwave probes, a microscope, and a network analyzer. The ability to perform microwave tests at high temperatures is becoming necessary. There is now a need for sensors and communication circuits that can operate at 500 C and above for aircraft engine development and monitoring during flight. To address this need, researchers have fabricated devices using wide bandgap semiconductors such as SiC with targeted operating temperatures of 500 to 600 C. However, the microwave properties of these devices often change drastically with temperature, so any designs that are intended to be used in such an environment must be characterized at high temperatures. For some reliability, lifetime, and direct-current testing, the device under test can be packaged and characterized in an oven. However, for RF and microwave measurements, it is usually not possible to establish a calibrated reference plane at the device terminals within a package. In addition, the characteristics of the package would vary over a 500 C temperature range, and this would have to be accounted for when the data were analyzed. A high temperature probe station allows circuits and devices to be characterized through on wafer measurements across a broad temperature range with known reference plane. The conventional, commercially available thermal wafer-probe stations that are used to evaluate microwave devices across a controlled temperature range have a typical upper limit of 200 C. Standalone thermal heating chucks are available with an extended upper temperature range of 300 to 400 C. To effectively characterize devices at temperatures up to and surpassing 500 C, Glenn researchers developed a custom probe station. In the past, custom probe stations have been developed to test devices under other extreme environments, such as cryogenic temperatures as low as 37 K. Similarly, this custom probe station was specifically modified for high-temperature use. It allows devices to be measured quickly and flexibly, without the use of wire bonds and test fixtures. The probe station is shown making scattering parameter measurements from 1 to 50 GHz with a Hewlett-Packard 8510C Network Analyzer. There is a half-wafer of silicon directly on top of the heater to provide a uniform heated platform for our sample. A quarter wafer of silicon carbide forms the substrate for our test circuit of several transmission lines.

Downey, Alan N.↗

NASA NTRS1984

Inertial storage for satellites

A new system is being developed that performs satellite attitude control, attitude reference, and energy storage utilizing inertia wheels. The baseline approach consists of two counter rotating flywheels suspended in specially designed magnetic bearings, spin axis motor/generators, and a control system. The control system regulates the magnetic bearings and spin axis motor/generators and interacts with other satellite subsystems (photovoltaic array, star trackers, Sun sensors, magnetic torquers, etc.) to perform the three functions. Existing satellites utilize separate subsystems to perform attitude control, provide attitude reference, and store energy. These functions are currently performed using reaction or momentum wheels, gyros, batteries, and devices that provide an absolute reference (Sun sensors and star trackers). A Combined Attitude, Reference, and Energy Storage (CARES) system based on high energy density inertial energy storage wheels (flywheels) has potential advantages over existing technologies. Even when used only for energy storage, this system offers the potential for substantial improvements in life, energy efficiency, and weight over existing battery technologies. Utilizing this same device for both attitude control and attitude reference would result in significant additional savings in overall satellite weight and complexity.

Eisenhaure, D.↗

NASA NTRS2002

Thermocouple Boundary Layer Rake

Apparatus and method for providing a velocity flow profile near a reference surface. A measuring device utilizes a plurality of thermojunction pairs to provide the velocity flow profile in accordance with behavior of a gas relative to a constant thickness strut which stands vertically from the reference surface such that the span is normal to the surface, and the chord is parallel to the surface along the initial flow direction. Each thermojunction is carried on either side of a heater formed on a measuring surface in a constant thickness portion of a strut. Additionally, each thermojunction of a given pair is located at a predetermined height from the reference surface. Gas velocity data obtained from temperature differentials from one side of the heater to the other at each successive height is utilized to generate the velocity and turbulence level profiles.

Danny P Hwang↗

NASA NTRS1999

Subsonic Aerodynamic Assessment of Vortex Flow Management Devices on a High-Speed Civil Transport Configuration

An experimental investigation of the effects of leading-edge vortex management devices on the subsonic performance of a high-speed civil transport (HSCT) configuration was conducted in the Langley 14- by 22-Foot Subsonic Tunnel. Data were obtained over a Mach number range of 0.14 to 0.27, with corresponding chord Reynolds numbers of 3.08 x 10 (sup 6) to 5.47 x 10 (sup 6). The test model was designed for a cruise Mach number of 2.7. During the subsonic high-lift phase of flight, vortical flow dominates the upper surface flow structure, and during vortex breakdown, this flow causes adverse pitch-up and a reduction of usable lift. The experimental results showed that the beneficial effects of small leading-edge vortex management devices located near the model reference center were insufficient to substantially affect the resulting aerodynamic forces and moments. However, devices located at or near the wiring apex region demonstrated potential for pitch control with little effect on overall lift.

Campbell, Bryan A.↗

NASA NTRS1982

Aeroacoustic performance of an externally blown flap configuration with several flap noise suppression devices

Small scale model acoustic experiments were conducted to measure the noise produced in the flyover and sideline planes by an engine under the wing externally blown flap configuration in its approach attitude. Broadband low frequency noise reductions as large as 9 dB were produced by reducing the separation distance between the nozzle exhaust plane and the flaps. Experiments were also conducted to determine the noise suppression effectiveness in comparison with a reference configuration of three passive types of devices that were located on the jet impingement surfaces of the reference configuration. These devices produced noise reductions that varied up to 10 dB at reduced separation distances. In addition, a qualitative estimate of the noise suppression characteristics of the separate devices was made. Finally static aerodynamic performance data were obtained to evaluate the penalties incurred by these suppression devices. The test results suggest that further parametric studies are required in order to understand more fully the noise mechanisms that are affected by the suppression devices used.

Mckinzie, D. J., Jr.↗

NASA NTRS2011

Performance of the Micropower Voltage Reference ADR3430 Under Extreme Temperatures

Electronic systems designed for use in space exploration systems are expected to be exposed to harsh temperatures. For example, operation at cryogenic temperatures is anticipated in space missions such as polar craters of the moon (-223 C), James Webb Space Telescope (-236 C), Mars (-140 C), Europa (-223 C), Titan (-178 C), and other deep space probes away from the sun. Similarly, rovers and landers on the lunar surface, and deep space probes intended for the exploration of Venus are expected to encounter high temperature extremes. Electronics capable of operation under extreme temperatures would not only meet the requirements of future spacebased systems, but would also contribute to enhancing efficiency and improving reliability of these systems through the elimination of the thermal control elements that present electronics need for proper operation under the harsh environment of space. In this work, the performance of a micropower, high accuracy voltage reference was evaluated over a wide temperature range. The Analog Devices ADR3430 chip uses a patented voltage reference architecture to achieve high accuracy, low temperature coefficient, and low noise in a CMOS process [1]. The device combines two voltages of opposite temperature coefficients to create an output voltage that is almost independent of ambient temperature. It is rated for the industrial temperature range of -40 C to +125 C, and is ideal for use in low power precision data acquisition systems and in battery-powered devices. Table 1 shows some of the manufacturer s device specifications.

Patterson, Richard L.↗