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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 217 records · Page 12

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NASA NTRS2013

Testing of the Advanced Stirling Radioisotope Generator Engineering Unit at NASA Glenn Research Center

The Advanced Stirling Radioisotope Generator (ASRG) is a high-efficiency generator being developed for potential use on a Discovery 12 space mission. Lockheed Martin designed and fabricated the ASRG Engineering Unit (EU) under contract to the Department of Energy. This unit was delivered to NASA Glenn Research Center in 2008 and has been undergoing extended operation testing to generate long-term performance data for an integrated system. It has also been used for tests to characterize generator operation while varying control parameters and system inputs, both when controlled with an alternating current (AC) bus and with a digital controller. The ASRG EU currently has over 27,000 hours of operation. This paper summarizes all of the tests that have been conducted on the ASRG EU over the past 3 years and provides an overview of the test results and what was learned.

Lewandowski, Edward J.↗

NASA NTRS2011

Crew Field Notes: A New Tool for Planetary Surface Exploration

The Desert Research and Technology Studies (DRATS) field tests of 2010 focused on the simultaneous operation of two rovers, a historical first. The complexity and data volume of two rovers operating simultaneously presented significant operational challenges for the on-site Mission Control Center, including the real time science support function. The latter was split into two "tactical" back rooms, one for each rover, that supported the real time traverse activities; in addition, a "strategic" science team convened overnight to synthesize the day's findings, and to conduct the strategic forward planning of the next day or days as detailed in [1, 2]. Current DRATS simulations and operations differ dramatically from those of Apollo, including the most evolved Apollo 15-17 missions, due to the advent of digital technologies. Modern digital still and video cameras, combined with the capability for real time transmission of large volumes of data, including multiple video streams, offer the prospect for the ground based science support room(s) in Mission Control to witness all crew activities in unprecedented detail and in real time. It was not uncommon during DRATS 2010 that each tactical science back room simultaneously received some 4-6 video streams from cameras mounted on the rover or the crews' backpacks. Some of the rover cameras are controllable PZT (pan, zoom, tilt) devices that can be operated by the crews (during extensive drives) or remotely by the back room (during EVAs). Typically, a dedicated "expert" and professional geologist in the tactical back room(s) controls, monitors and analyses a single video stream and provides the findings to the team, commonly supported by screen-saved images. It seems obvious, that the real time comprehension and synthesis of the verbal descriptions, extensive imagery, and other information (e.g. navigation data; time lines etc) flowing into the science support room(s) constitute a fundamental challenge to future mission operations: how can one analyze, comprehend and synthesize -in real time- the enormous data volume coming to the ground? Real time understanding of all data is needed for constructive interaction with the surface crews, and it becomes critical for the strategic forward planning process.

Horz, Friedrich↗

NASA NTRS1988

Successful completion of a cyclic ground test of a mercury ion auxiliary propulsion system

An engineering model Ion Auxiliary Propulsion System (IAPS) 8-cm thruster (S/N 905) has completed a life test at NASA Lewis Research Center. The mercury ion thruster successfully completed and exceeded the test goals of 2557 on/off cycles and 7057 hr of operation at full thrust. The final 1200 cycles and 3600 hr of the life test were conducted using an engineering model of the IAPS power electronics unit (PEU) and breadboard digital controller and interface unit (DCIU). This portion of the test is described in this paper with a charted history of thruster operating parameters and off-normal events. Performance and operating characteristics were constant throughout the test with only minor variations. The engineering model power electronics unit operated without malfunction; the flight software in the digital controller and interface unit was exercised and verified. Post-test inspection of the thruster revealed facility enhanced accelerator grid erosion but overall the thruster was in good condition. It was concluded that the thruster performance was not drastically degraded by time or cycles. Additional cyclic testing is currently under consideration.

Francisco, David R.↗

NASA NTRS1988

Successful completion of a cyclic ground test of a mercury Ion Auxiliary Propulsion System

Francisco, David R.↗

NASA NTRS1994

A new piston control strategy for segmented mirrors

One approach to the adaptive control of large segmented mirrors involves sending tilt commands to each segment and allowing each segment to minimize the distance between its edges and those of (all or some of) its neighbors. This approach has been adopted in the Phased Array Mirror, Extendible Large Aperture (PAMELA) testbed now located at NASA's Marshall Space Flight Center, Huntsville, AL. This approach minimizes (1) the communication between the sensors and the segment actuators and (2) computations required by the central controlling computer. This report discusses issues that large segmented mirrors built around the PAMELA concept (such as SELENE) will face when they migrate to integrated, and presumably to digital, on-segment computational ability and high bandwidth response.

Olivier, Philip D.↗

NASA NTRS2005

New Applications for the Testing and Visualization of Wireless Networks

Traditional techniques for examining wireless networks use physical link characteristics such as Signal-to-Noise (SNR) ratios to assess the performance of wireless networks. Such measurements may not be reliable indicators of available bandwidth. This work describes two new software applications developed at NASA Glenn Research Center for the investigation of wireless networks. GPSIPerf combines measurements of Transmission Control Protocol (TCP) throughput with Global Positioning System (GPS) coordinates to give users a map of wireless bandwidth for outdoor environments where a wireless infrastructure has been deployed. GPSIPerfView combines the data provided by GPSIPerf with high-resolution digital elevation maps (DEM) to help users visualize and assess the impact of elevation features on wireless networks in a given sample area. These applications were used to examine TCP throughput in several wireless network configurations at desert field sites near Hanksville, Utah during May of 2004. Use of GPSIPerf and GPSIPerfView provides a geographically referenced picture of the extent and deterioration of TCP throughput in tested wireless network configurations. GPSIPerf results from field-testing in Utah suggest that it can be useful in assessing other wireless network architectures, and may be useful to future human-robotic exploration missions.

Griffin, Robert I.↗

NASA NTRS2014

Optical Multi-Gas Monitor Technology Demonstration on the International Space Station

There are a variety of both portable and fixed gas monitors onboard the International Space Station (ISS). Devices range from rack-mounted mass spectrometers to hand-held electrochemical sensors. An optical Multi-Gas Monitor has been developed as an ISS Technology Demonstration to evaluate long-term continuous measurement of 4 gases. Based on tunable diode laser spectroscopy, this technology offers unprecedented selectivity, concentration range, precision, and calibration stability. The monitor utilizes the combination of high performance laser absorption spectroscopy with a rugged optical path length enhancement cell that is nearly impossible to misalign. The enhancement cell serves simultaneously as the measurement sampling cell for multiple laser channels operating within a common measurement volume. Four laser diode based detection channels allow quantitative determination of ISS cabin concentrations of water vapor (humidity), carbon dioxide, ammonia and oxygen. Each channel utilizes a separate vertical cavity surface emitting laser (VCSEL) at a different wavelength. In addition to measuring major air constituents in their relevant ranges, the multiple gas monitor provides real time quantitative gaseous ammonia measurements between 5 and 20,000 parts-per-million (ppm). A small ventilation fan draws air with no pumps or valves into the enclosure in which analysis occurs. Power draw is only about 3 W from USB sources when installed in Nanoracks or when connected to 28V source from any EXPRESS rack interface. Internal battery power can run the sensor for over 20 hours during portable operation. The sensor is controlled digitally with an FPGA/microcontroller architecture that stores data internally while displaying running average measurements on an LCD screen and interfacing with the rack or laptop via USB. Design, construction and certification of the Multi-Gas Monitor were a joint effort between Vista Photonics, Nanoracks and NASA-Johnson Space Center (JSC). Vista Photonics developed the core technology and built the sensor. Nanoracks designed, constructed the enclosure, interfaces, and battery power management circuitry, integrated all subsystems into the enclosure, and then managed the certification tests, documentation and manifesting. The unit was calibrated in the JSC Toxicology Laboratory. The Multi-Gas Monitor is manifested to fly as a technology demonstration to the ISS in November 2013 and will operate for at least 6 months with data sent to the ground for evaluation. The primary goal is to demonstrate long term interference free operation in the real spacecraft environment.

Pilgrim, Jeffrey S.↗

DOE OSTI2020

Design and performance of an in-vacuum, magnetic field mapping system for the Muon g-2 experiment

The Muon g - 2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment, a μ , of the muon with a precision of 140 parts-per-billion. This requires a precise measurement of both the anomalous spin precession frequency, ω α , of muons stored in a magnetic field of 1.45 T, and a precise measurement of that magnetic field in terms of the shielded proton Larmor frequency, ω' ρ . The measurement of ω' ρ with a total systematic uncertainty of 70 parts-perbillion involves a combination of various nuclear magnetic resonance (NMR) probes. There are 378 probes mounted in fixed locations that constantly monitor field drifts. A water-based, cylindrical calibration probe provides the calibration in terms of the shielded proton Larmor frequency. A crucial element for the multi-step measurement of ω' ρ is the regular mapping of the magnetic field over the muon storage region. The former experiment at Brookhaven National Laboratory (BNL) employed an in-vacuum field mapping system equipped with 17 NMR probes, which was developed by the University of Heidelberg. We have refurbished and upgraded this system with new probes and electronics. The upgrades include the addition of 16-bit, 1 MSPS digitization of the NMR signals, which replaced the hardware-implemented zero-crossing counting of the system at Brookhaven. The digitized signals offer new capabilities in the NMR frequency analysis and its related systematic uncertainties. To sustain the higher data rates, a new communication scheme with time-division multiplexing was implemented to separate the important NMR reference clock from the data communication in order to reach the specifications for the accuracy and stability of the reference clock. A new barcode reader provides more precise azimuthal position determination during the measurement and calibration. While the mechanical systems that move the field mapper inside the storage ring have been mostly refurbished from BNL, the motion control system was completely replaced with a custom-built electronics centered around a commercial Galil motion controller. Both the field mapping NMR system and its motion control were successfully commissioned at Fermilab and have been in reliable operation during the first three data taking periods of the experiment at Fermilab. Finally, this article will provide the details of the upgrades of the field mapper and its performance.

47 OTHER INSTRUMENTATION↗

NASA NTRS1976

Research in ground-based near-terminal area 4D guidance and control

This paper describes work being done at NASA, Langley Research Center and at the Research Triangle Institute on advanced, ground-based guidance and control for the near terminal area. Large-scale computer traffic simulations in conjunction with flight experiments with a Boeing 737 aircraft will be used to evaluate various concepts for automated terminal area metering and spacing. The all-digital real-time air traffic simulation model is described. Facilities for aircraft tracking and for interfacing the aircraft with the digital simulation are discussed, along with possible application to other types of experiments.

Britt, C. L., Jr.↗

NASA NTRS1986

Phase-Measuring System

System developed and used at Langley Research Center measures phase between two signals of same frequency or between two signals, one of which is harmonic multiple of other. Simple and inexpensive device combines digital and analog components to give accurate phase measurements. One signal at frequency f fed to pulse shaper, produces negative pulse at time t4. Pulse applied to control input of sample-and-hold module 1. Second signal, at frequency nf, fed to zero-crossover amplifier, producing square wave at time t. Signal drives first one-shot producing narrow negative pulse at t1. Signal then drives second one-shot producing narrow positive pulse at time t2. This pulse used to turn on solid-state switch and reset integrator circuit to zero.

Davis, W. T.↗

NASA NTRS1993

Electromechanical actuation for cryogenic valve control

The design and analysis of the electromechanical actuator (EMA) being developed for the NASA/Marshall Space Flight Center as part of the National Launch System (NLS) Propellant Control Effector Advanced Development Program (ADP) are addressed. The EMA design uses several proven technologies combined into a single modular package which includes single stage high ratio gear reduction, redundant electric motors mounted on a common drive shaft, redundant drive and control electronics, and digital technology for performing the closed loop position feedback, communication, and health monitoring functions. Results of tests aimed at evaluating both component characteristics and overall system performance demonstrated that the goal of low cost, reliable control in a cryogenic environment is feasible.

Lister, M. J.↗

NASA NTRS2011

RATIR: Reionization and Transients Infra-Red Camera. A New Instrument to Identify High Red-Shift GRBs

We are currently constructing the cryogenic infrared portion of the RATIR instrument at NASA's Goddard Space Flight Center (GSFC) in collaboration with University of California, Berkeley (UCB) and The University of Mexico (UNAM). The infrared instrument will consist of two 2048x2048 Hawaii 2RG detectors, one on axis and one off axis using diachronic. The detectors will be operated using state-of-the-art Teledyne SIDECAR (System Image, Digitizing, Enhancing, Controlling, And Retrieving) ASICs (Application- Specific Integrated Circuits) similar to NIRSpec on JWST. The visible portion of the instrument is currently being developed at UCB consisting of two CCD imagining cameras. Once completed, the two sections will be integrated into the RATIR instrument. Mounted on a dedicated, fully-automated 1.5-m telescope, the instrument will provide rapid (<10 min) identification of VHR GRBs allowing high-resolution spectroscopic follow-up observations with large aperture telescopes possible. The hosting Observatorio Astronomico Nacional of the Universidad Nacional Autonoma de Mexico (UNAM), located on the Sierra de San Pedro Martir in Baja California, Mexico, provides great seeing (-1 aresec), good weather, dark skies, and significant sky coverage so that RATIR will detect a significant number of Swift afterglows. While not all GRBs will be at high red shifts, the resulting light curves, combined with X-ray/UV observations, will address several open questions, including the nature of both "dark GRBs" and the GRB emission mechanism.

Rapchun, David A.↗

NASA NTRS2011

Crush Test Abuse Stand

The purpose of this system is to simulate an internal short on battery cells by causing deformation (a crushing force) in a cell without penetration. This is performed by activating a hydraulic cylinder on one side of a blast wall with a hydraulic pump located on the other. The operator can control the rate of the crush by monitoring a local pressure gauge connected to the hydraulic cylinder or a load cell digital display located at the hydraulic pump control area. The internal short simulated would be considered a worst-case scenario of a manufacturer fs defect. This is a catastrophic failure of a cell and could be a very destructive event. Fully charged cells are to have an internal short simulated at the center of the length of the cell (away from terminals). The crush can be performed with a .- to 1-in. (.0.6- to 2.5-cm) rod placed crossways to the cell axis, causing deformation of the cell without penetration. The OCV (open-circuit voltage) and temperature of the cells, as well as the pressure and crushing force, are recorded during the operation. Occurrence of an internal short accompanied by any visible physical changes such as venting, fires, or explosions is reported. Typical analytical data examined after the test would be plots of voltage, temperature, and pressure or force versus time. The rate of crushing force can be increased or decreased based on how fast the operator pumps the hydraulic pump. The size of cylinder used to compress the battery cell can be easily changed by adding larger or smaller fittings onto the end of the hydraulic cylinder based on the battery/cell size being tested. The cell is crushed remotely and videotaped, allowing the operator to closely monitor the situation from a safe distance.

Collins, Jacob↗

NASA NTRS1983

A generalized computer code for developing dynamic gas turbine engine models (DIGTEM)

This paper describes DIGTEM (digital turbofan engine model), a computer program that simulates two spool, two stream (turbofan) engines. DIGTEM was developed to support the development of a real time multiprocessor based engine simulator being designed at the Lewis Research Center. The turbofan engine model in DIGTEM contains steady state performance maps for all the components and has control volumes where continuity and energy balances are maintained. Rotor dynamics and duct momentum dynamics are also included. DIGTEM features an implicit integration scheme for integrating stiff systems and trims the model equations to match a prescribed design point by calculating correction coefficients that balance out the dynamic equations. It uses the same coefficients at off design points and iterates to a balanced engine condition. Transients are generated by defining the engine inputs as functions of time in a user written subroutine (TMRSP). Closed loop controls can also be simulated. DIGTEM is generalized in the aerothermodynamic treatment of components. This feature, along with DIGTEM's trimming at a design point, make it a very useful tool for developing a model of a specific turbofan engine.

Daniele, C. J.↗

NASA NTRS1984

A generalized computer code for developing dynamic gas turbine engine models (DIGTEM)

Daniele, C. J.↗

NASA NTRS2004

Space Station Biological Research Project (SSBRP) Cell Culture Unit (CCU) and incubator for International Space Station (ISS) cell culture experiments

The CCU and Incubator are habitats under development by SSBRP for gravitational biology research on ISS. They will accommodate multiple specimen types and reside in either Habitat Holding Racks, or the Centrifuge Rotor, which provides selectable gravity levels of up to 2 g. The CCU can support multiple Cell Specimen Chambers, CSCs (18, 9 or 6 CSCs; 3, 10 or 30 mL in volume, respectively). CSCs are temperature controlled from 4-39 degrees C, with heat shock to 45 degrees C. CCU provides automated nutrient supply, magnetic stirring, pH/O2 monitoring, gas supply, specimen lighting, and video microscopy. Sixty sample containers holding up to 2 mL each, stored at 4-39 degrees C, are available for automated cell sampling, subculture, and injection of additives and fixatives. CSCs, sample containers, and fresh/spent media bags are crew-replaceable for long-term experiments. The Incubator provides a 4-45 degrees C controlled environment for life science experiments or storage of experimental reagents. Specimen containers and experiment unique equipment are experimenter-provided. The Specimen Chamber exchanges air with ISS cabin and has 18.8 liters of usable volume that can accommodate six trays and the following instrumentation: five relocatable thermometers, two 60 W power outlets, four analog ports, and one each relative humidity sensor, video port, ethernet port and digital input/output port.

NASA Center ARC↗

NASA NTRS1992

Laser-based strain measurements for high temperature applications

The Instrumentation and Control Technology Division at NASA Lewis Research Center has developed a high performance optical strain measurement system for high temperature applications using wires and fibers. The system is based on Yamaguchi's two-beam speckle-shift strain measurement technique. The system automatically calculates surface strains at a rate of 5 Hz using a digital signal processor in a high speed micro-computer. The system is fully automated, and can be operated remotely. This report describes the speckle-shift technique and the latest NASA system design. It also shows low temperature strain test results obtained from small diameter tungsten, silicon carbide, and sapphire specimens. These specimens are of interest due to their roles in composite materials research at NASA Lewis.

Lant, Christian T.↗

NASA NTRS1981

A microcomputer based data acquisition system and experiment controller

A data acquisition system is described. The system monitors and records the signal strength of a radio beacon sent to Earth from a geosynchronous satellite. It acquires data from several devices such as a radar, a radiometer, and a rain gauge which monitor the meteorological conditions along the Earth space propagation path. The acquired data are stored in digital format on magnetic tape for analysis at the computer center. A detailed description of the design and operation of the system's various hardware components is given. Schematic diagrams, the theory of operation, and normal operating procedures are presented.

Ganz, M. W.↗