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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 sourcesNASA NTRSDOE OSTI
NASA NTRS1974

LST and instrument considerations

In order that the LST meet its scientific objectives and also be a National Astronomical Space Facility during the 1980's and 1990's, broad requirements have been levied by the scientific community. These scientific requirements can be directly translated into design requirements and specifications for the scientific instruments. The instrument ensemble design must be consistent with a 15-year operational lifetime. Downtime for major repair/refurbishment or instrument updating must be minimized. The overall efficiency and performance of the instruments should be maximized. Modularization of instruments and instrument subsystems, some degree of on-orbit servicing (both repair and replacement), on-axis location, minimizing the number of reflections within instruments, minimizing polarization effects, and simultaneous operation of the F/24 camera with other instruments, are just a few of the design guidelines and specifications which can and will be met in order that these broader scientific requirements be satisfied.-

Levin, G. M.↗
NASA NTRS1976

Display/control requirements for automated VTOL aircraft

A systematic design methodology for pilot displays in advanced commercial VTOL aircraft was developed and refined. The analyst is provided with a step-by-step procedure for conducting conceptual display/control configurations evaluations for simultaneous monitoring and control pilot tasks. The approach consists of three phases: formulation of information requirements, configuration evaluation, and system selection. Both the monitoring and control performance models are based upon the optimal control model of the human operator. Extensions to the conventional optimal control model required in the display design methodology include explicit optimization of control/monitoring attention; simultaneous monitoring and control performance predictions; and indifference threshold effects. The methodology was applied to NASA's experimental CH-47 helicopter in support of the VALT program. The CH-47 application examined the system performance of six flight conditions. Four candidate configurations are suggested for evaluation in pilot-in-the-loop simulations and eventual flight tests.

Hoffman, W. C.↗
NASA NTRS1990

An airborne compatible photofragmentation two-photon laser-induced fluorescence instrument for measuring background tropospheric levels of NO, NO(x), and NO2

The operating principle, design, and performance of a two-photon LIF (TP-LIF) sensor for simultaneous measurements of NO, NO(x) (NO + NO2), and NO2 are described. In this instrument, NO is first measured by direct spectroscopic TP-LIF detection; NO2 is converted to NO by photofragmentation using an XeF excimer laser operating at 353 nm; and the resulting NO is then detected quantitatively by TP-LIF. The detection limits of the instrument are found to be 3.5 parts per trillion by volume (pptv) of NO and 10 pptv for NO2, with integration times of 2 and 6 min, respectively. The in-flight performance of the instrument was evaluated during the NASA Global Tropospheric Experiment Chemical Instrumentation Test and Evaluation 2 program in summer 1986, as reported by Gregory et al. (1990).

Sandholm, S. T.↗
NASA NTRS1994

Global and regional kinematics with VLBI

Since a VLBI station cannot operate in isolation and since simultaneous operation of the entire VLBI network is impractical, it is necessary to design observing programs with periodic observing sessions using networks of 3-7 stations that, when treated together, will have the necessary interstation data and network overlaps to determine the desired rates of change. Thus, there has been a mix of global, intercontinental, transcontinental, and regional networks to make measurements ranging from plate motions to deformation over a few hundred km. Over time, even networks focusing on regional deformation using mobile VLBI included large stations removed by several thousand km to increase sensitivity, determine EOP more accurately, and provide better ties to the terrestrial reference frame (TRF). Analysis products have also evolved, beginning with baseline components, and then to full three-dimensional site velocities in a global TRF.

Ma, Chopo↗
NASA NTRS2007

The Next Giant Leap: NASA's Ares Launch Vehicles Overview

The National Aeronautics and Space Administration (NASA)'s Constellation Program is developing new launch vehicles (Ares) and spacecraft (Orion) to send astronauts to the Moon, Mars, and beyond. This paper presents plans, projections, and progress toward fielding the Ares I and Ares V vehicles, and the Ares I-X test flight in 2009. NASA is building on both new research and aeronautical capabilities, as well as lessons learned from almost 50 years of aerospace experience. The Ares Projects Office (APO) completed the Ares I System Requirements Review (SRR) in 2006 and the System Definition Review in autumn 2007; and will focus on the Preliminary Design Review in 2008. Ares I is currently being refined to meet safety, operability, reliability, and affordability goals. The Ares team is simultaneously testing Ares I elements and building hardware for Ares I-X, while the Ares V is in the early design stage, with the team validating requirements and ensuring commonality with Ares I. Ares I and V are key to opening the space frontier for peaceful endeavors.

Cook, Stephen A.↗
NASA NTRS1972

The 20 and 30 GHz communications system for the ATS-F millimeter wave experiment.

The first space communications system operating at millimeter wavelengths is planned for the sixth Applications Technology Satellite (ATS-F), scheduled for launch in May of 1973. The ATS-F experiment is designed to provide engineering data on wideband space-to-earth transmissions at 20 and 30 GHz as a function of meteorological conditions and modulation techniques. The system design for both the spacecraft and ground station portions of the experiment is presented, and the unique design characteristics of these relatively new and unexplored frequency bands are emphasized. The experiment is designed to provide wideband 1440-MHz propagation links and 40-Megabit communications links with simultaneous operation at 20, 30, and 4 GHz for link comparisons.

Ippolito, L. J.↗
NASA NTRS1997

Applied Virtual Reality in Reusable Launch Vehicle Design, Operations Development, and Training

Application of Virtual Reality (VR) technology offers much promise to enhance and accelerate the development of Reusable Launch Vehicle (RLV) infrastructure and operations while simultaneously reducing developmental and operational costs. One of the primary cost areas in the RLV concept that is receiving special attention is maintenance and refurbishment operations. To produce and operate a cost effective RLV, turnaround cost must be minimized. Designing for maintainability is a necessary requirement in developing RLVs. VR can provide cost effective methods to design and evaluate components and systems for maintenance and refurbishment operations. The National Aeronautics and Space Administration (NASA)/Marshall Space Flight Center (MSFC) is beginning to utilize VR for design, operations development, and design analysis for RLVs. A VR applications program has been under development at NASA/MSFC since 1989. The objectives of the MSFC VR Applications Program are to develop, assess, validate, and utilize VR in hardware development, operations development and support, mission operations training and science training. The NASA/MSFC VR capability has also been utilized in several applications. These include: 1) the assessment of the design of the late Space Station Freedom Payload Control Area (PCA), the control room from which onboard payload operations are managed; 2) a viewing analysis of the Tethered Satellite System's (TSS) "end-of-reel" tether marking options; 3) development of a virtual mockup of the International Space Welding Experiment for science viewing analyses from the Shuttle Remote Manipulator System elbow camera and as a trainer for ground controllers; and 4) teleoperations using VR. This presentation will give a general overview of the MSFC VR Applications Program and describe the use of VR in design analyses, operations development, and training for RLVs.

Hale, Joseph P.↗
NASA NTRS1990

Innovative operating modes and techniques for the spaceborne imaging radar-C instrument

The operation of the spaceborne imaging radar-C (SIR-C) is discussed. The SIR-C instrument has been designed to obtain simultaneous multifrequency and simultaneous multipolarization radar images from a low earth orbit. It is a multiparameter imaging radar which will be flown during at least two different seasons. The instrument has been designed to operate in innovative modes such as the squint alignment mode, the extended aperture mode, the scansar mode, and the interferometry mode. The instrument has been designed to demonstrate innovative engineering techniques such as beam nulling for echo tracking, pulse-repetition frquency hopping for Doppler centroid tracking, generating the frequency step chirp for radar parameter flexibility, block floating point quantizing for data rate compression, and elevation beamwidth broadening for increasing the swath illumination.

Huneycutt, Bryan L.↗
NASA NTRS1991

Damping and structural control of the JPL phase 0 testbed structure

This paper describes recent advances in structural quieting technology as applied to active truss structures intended for high precision space based optics applications. The active structure incorporates piezoelectric active members which exert control forces internal to the structure and thereby improve the structure's dimensional stability. The control architecture involves two layers of feedback control. The first utilizes collocated measurements of force and velocity at the active member to achieve active damping, the second utilizes noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The local control loops are based on the concept of impedance matching, the global control loops are designed using robust control methods. These two levels of control are intended to operate simultaneously; however, in this paper each approach is applied individually. The combined implementation is left for future work.

Fanson, James L.↗
NASA NTRS1999

Rotor Re-Design for the SSME Fuel Flowmeter

The present report describes the process of redesigning a new rotor for the SSME Fuel Flowmeter. The new design addresses the specific requirement of a lower rotor speed which would allow the SSME operation at 1 15% rated power level without reaching a blade excitation by the wakes behind the hexagonal flow straightener upstream at frequencies close to the blade natural frequency. A series of calculations combining fleet flowmeters test data, airfoil fluid dynamics and CFD simulations of flow patterns behind the flowmeter's hexagonal straightener has led to a blade twist design alpha = alpha (radius) targeting a kf constant of 0.8256. The kf constant relates the fuel volume flow to the flowmeter rotor speed, for this particular value 17685 GPM at 3650 RPM. Based on this angle distribution, two actual blade designs were developed. A first design using the same blade airfoil as the original design targeted the new kf value only. A second design using a variable blade chord length and airfoil relative thickness targeted simultaneously the new kf value and an optimum blade design destined to provide smooth and stable operation and a significant increase in the blade natural frequency associated with the first bending mode, such that a comfortable margin could be obtained at 115% RPL. The second design is a result of a concurrent engineering process, during which several iterations were made in order to achieve a targeted blade natural frequency associated with the first bending mode of 1300 Hz. Water flow tests preliminary results indicate a kf value of 0.8179 for the f-irst design, which is within 1% of the target value. The second design rotor shows a natural frequency associated with the first bending mode of 1308 Hz, and a water-flow calibration constant of kf 0.8169.

Marcu, Bogdan↗
NASA NTRS1972

Multispectral imaging radar

A side-looking radar, installed in a C-46 aircraft, was modified to provide it with an initial multispectral imaging capability. The radar is capable of radiating at either of two wavelengths, these being approximately 3 cm and 30 cm, with either horizontal or vertical polarization on each wavelength. Both the horizontally- and vertically-polarized components of the reflected signal can be observed for each wavelength/polarization transmitter configuration. At present, two-wavelength observation of a terrain region can be accomplished within the same day, but not with truly simultaneous observation on both wavelengths. A multiplex circuit to permit this simultaneous observation has been designed. A brief description of the modified radar system and its operating parameters is presented. Emphasis is then placed on initial flight test data and preliminary interpretation. Some considerations pertinent to the calibration of such radars are presented in passing.

Porcello, L. J.↗
NASA NTRS1982

Interactive digital signal processor

The Interactive Digital Signal Processor (IDSP) is examined. It consists of a set of time series analysis Operators each of which operates on an input file to produce an output file. The operators can be executed in any order that makes sense and recursively, if desired. The operators are the various algorithms used in digital time series analysis work. User written operators can be easily interfaced to the sysatem. The system can be operated both interactively and in batch mode. In IDSP a file can consist of up to n (currently n=8) simultaneous time series. IDSP currently includes over thirty standard operators that range from Fourier transform operations, design and application of digital filters, eigenvalue analysis, to operators that provide graphical output, allow batch operation, editing and display information.

Mish, W. H.↗
NASA NTRS1992

Onset conditions for gas phase reaction and nucleation in the CVD of transition metal oxides

A combined experimental/theoretical study is presented of the onset conditions for gas phase reaction and particle nucleation in hot substrate/cold gas CVD of transition metal oxides. Homogeneous reaction onset conditions are predicted using a simple high activation energy reacting gas film theory. Experimental tests of the basic theory are underway using an axisymmetric impinging jet CVD reactor. No vapor phase ignition has yet been observed in the TiCl4/O2 system under accessible operating conditions (below substrate temperature Tw = 1700 K). The goal of this research is to provide CVD reactor design and operation guidelines for achieving acceptable deposit microstructures at the maximum deposition rate while simultaneously avoiding homogeneous reaction/nucleation and diffusional limitations.

Collins, J.↗
NASA NTRSDate not supplied

Orion Backup Flight Software

Orion Backup Flight Software (BFS) is a joint NASA/Lockheed Martin effort designed to prevent the loss of the Orion crew. BFS will only take over in the event the primary flight software (PFSW) fails to operate properly due to either hardware or software failures. Since the PFSW runs identical software on identical hardware, it is conceivable that a single issue could simultaneously bring down all the PFSW. To minimize the likelihood BFS would be affected by the same issue, BFS was specifically designed to be as different as possible from PFSW: BFS runs on different hardware, a separate operating system, a different compiler, does not share software libraries, and is written by a different team of programmers. This presentation will provide a high-level overview of the Artemis missions and the Orion vehicle, as well as provide additional details of the BFS system (including how BFS is different than the PFSW). The overall BFS capability evolution and timeline (milestones reached as well as work remaining) through the Artemis III mission will be discussed. Additionally, the verification and validation plans for BFS will be presented, describing how we ensure that only validated configuration data is loaded onto the flight vehicle. Finally, the presentation will close with lessons learned and future plans for Orion BFS.

Orion↗
NASA NTRSDate not supplied

Orion Backup Flight Software (BFS)

Orion Backup Flight Software (BFS) is a joint NASA/Lockheed Martin effort designed to prevent the loss of the Orion crew. BFS will only take over in the event the primary flight software (PFSW) fails to operate properly due to either hardware or software failures. Since the PFSW runs identical software on identical hardware, it is conceivable that a single issue could simultaneously bring down all the PFSW. To minimize the likelihood BFS would be affected by the same issue, BFS was specifically designed to be as different as possible from PFSW: BFS runs on different hardware, a separate operating system, a different compiler, does not share software libraries, and is written by a different team of programmers. This presentation will provide a high-level overview of the Artemis missions and the Orion vehicle, as well as provide additional details of the BFS system (including how BFS is different than the PFSW). The overall BFS capability evolution and timeline (milestones reached as well as work remaining) through the Artemis III mission will be discussed. Additionally, the verification and validation plans for BFS will be presented, describing how we ensure that only validated configuration data is loaded onto the flight vehicle. Finally, the presentation will close with lessons learned and future plans for Orion BFS.

CFS↗
NASA NTRS2012

Test Hardware Design for Flight-Like Operation of Advanced Stirling Convertors

NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, the Thermal Energy Conversion branch at GRC has been conducting extended operation of a multitude of free-piston Stirling convertors. The goal of this effort is to generate long-term performance data (tens of thousands of hours) simultaneously on multiple units to build a life and reliability database. The test hardware for operation of these convertors was designed to permit in-air investigative testing, such as performance mapping over a range of environmental conditions. With this, there was no requirement to accurately emulate the flight hardware. For the upcoming ASC-E3 units, the decision has been made to assemble the convertors into a flight-like configuration. This means the convertors will be arranged in the dual-opposed configuration in a housing that represents the fit, form, and thermal function of the ASRG. The goal of this effort is to enable system level tests that could not be performed with the traditional test hardware at GRC. This offers the opportunity to perform these system-level tests much earlier in the ASRG flight development, as they would normally not be performed until fabrication of the qualification unit. This paper discusses the requirements, process, and results of this flight-like hardware design activity.

Oriti, Salvatore M.↗
NASA NTRS2012

Test Hardware Design for Flightlike Operation of Advanced Stirling Convertors (ASC-E3)

NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, the Thermal Energy Conversion branch at GRC has been conducting extended operation of a multitude of free-piston Stirling convertors. The goal of this effort is to generate long-term performance data (tens of thousands of hours) simultaneously on multiple units to build a life and reliability database. The test hardware for operation of these convertors was designed to permit in-air investigative testing, such as performance mapping over a range of environmental conditions. With this, there was no requirement to accurately emulate the flight hardware. For the upcoming ASC-E3 units, the decision has been made to assemble the convertors into a flight-like configuration. This means the convertors will be arranged in the dual-opposed configuration in a housing that represents the fit, form, and thermal function of the ASRG. The goal of this effort is to enable system level tests that could not be performed with the traditional test hardware at GRC. This offers the opportunity to perform these system-level tests much earlier in the ASRG flight development, as they would normally not be performed until fabrication of the qualification unit. This paper discusses the requirements, process, and results of this flight-like hardware design activity.

Oriti, Salvatore M.↗