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At least 739 records · Page 41

Cold plasma processing of local planetary ores for oxygen and metallurgically important metals

The utilization of a cold plasma in chlorination processing is described. Essential equipment and instruments were received, the experimental apparatus assembled and tested, and preliminary experiments conducted. The results of the latter lend support to the original hypothesis: a cold plasma can both significantly enhance and bias chemical reactions. In two separate experiments, a cold plasma was used to reduce TiCl4 vapor and chlorinate ilmenite. The latter, reacted in an argon-chlorine plasma, yielded oxygen. The former experiment reveals that chlorine can be recovered as HCl vapor from metal chlorides in a hydrogen plasma. Furthermore, the success of the hydrogen experiments has lead to an analysis of the feasibility of direct hydrogen reduction of metal oxides in a cold plasma. That process would produce water vapor and numerous metal by-products.

Lynch, D. C.↗

Development of the Burst and Transient Source Experiment (BATSE)

The Burst and Transient Source Experiment (BATSE), one of four instruments on the Gamma Ray Observatory, consists of eight identical detector modules mounted on the corners of the spacecraft. Developed at MSFC, BATSE is the most sensitive gamma ray burst detector flown to date. Details of the assembly and test phase of the flight hardware development are presented. Results and descriptions of calibrations performed at MSFC, TRW, and KSC are documented extensively. With the presentation of each calibration results, the reader is provided with the means to access raw calibration data for further review or analysis.

Horack, J. M.↗

Lightning protection of full authority digital electronic systems

Modern electronic systems are vulnerable to transient and they now provide safety critical functions such as full authority digital electronic control (FADEC) units for fly by wire aircraft. Of the traditional suppression technologies available diodes have gained the wider acceptance, however, they lack the current handling capacity to meet existing threat levels. The development of high speed fold back devices where, at a specified voltage, the off state resistance switches to a very low on state one has provided the equivalent to a semiconductor spark gap. The size of the technology enables it to be integrated into connectors of interconnection cables. To illustrate the performance the technology was developed to meet the Lightning Protection requirements for FADEC units within aeroengines. Work was also carried out to study switching behavior with the waveform 5, the 500 us, 10 kA pulse applied to cable assemblies. This test enabled all the switches in a connector to be fired simultaneously.

Crofts, David↗

Integration by parts

This paper describes the unique integration and verification challenges associated with the Space Station Freedom and an approach to solve these problems using Data Management Systems (DMS) Kits. These DMS Kits will help alleviate the complex integration problems inherent in building, assembling and testing the Space Station. Particular emphasis has been placed on utilizing the capabilities and services of the on-board DMS to provide the integration and verification tools, not only for the DMS but for the other on-board distributed systems as well. DMS Kits are provided to system/software developers across the program. These DMS Kits provide a common set of integration and verification tools and hardware. Each system developer can then utilize, through the kits, a simulation of the complete data processing environment which will be available on orbit. The paper describes the evolution of the integration process from the system level to the final integration of multiple launch packages. DMS Kits are used throughout this process, which addresses both the ground and on-orbit aspects of the problem.

Barry, Thomas↗

Preliminary design of an advanced Stirling system for terrestrial solar energy conversion

A preliminary design was generated for an advanced Stirling conversion system (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. Stirling engines are being evaluated for terrestrial solar applications. A two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 h). The ACSC has a long-term cost goal of about $450 per kilowatt, exclusive of the 11-m parabolic dish concentrator. The proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. The major thrusts of the preliminary design are described, including material selection for the hot-end components, heat transport system (reflux pool boiler) design, system thermal response, improved manufacturability, FMECA/FTA analysis, updated manufacturing cost estimate, and predicted system performance.

White, M. A.↗

SP-100 space subsystems development progress

The space technology effort related to SP-100 subsystems is described in terms of the areas of primary focus and most significant progress. The SP-100 is briefly compared to the Voyager, and detailed descriptions of the converter subsystem, the heat-transport system, and the heat-rejection subsystem. Progress on the converter subsystem includes a high-voltage insulator composed of a single sapphire crystal, a compliant pad of coated niobium, an SiGe thermoelectric (TE) module, and a TE cell assembly. The test of the Nb1Zr piping related to the heat-transport subsystem is described, and the development is reported for the TEM pump and the gas separator. It is concluded that the critical technical issues related to the technologies have been addressed although further efforts are required. Future testing is described for the three major components of the space subsystems including the converter, pump, and the radiator.

Mondt, Jack F.↗

Information Flow Analysis of Level 4 Payload Processing Operations

The Level 4 Mission Sequence Test (MST) was studied to develop strategies and recommendations to facilitate information flow. Recommendations developed as a result of this study include revised format of the Test and Assembly Procedure (TAP) document and a conceptualized software based system to assist in the management of information flow during the MST.

Danz, Mary E.↗

A space crane concept for performing on-orbit assembly

The topics are presented in viewgraph form and include: in-space assembly and construction enhances future mission planning flexibility; in-space assembly and construction facility concept; space crane concept with mobile base; fundamental characteristics; space crane research approach; spacecraft component positioning and assembly test-bed; and articulating joint testbed.

John T Dorsey↗

Orbit transfer vehicle engine technology program. Task B-6 high speed turbopump bearings

Bearing types were evaluated for use on the Orbit Transfer Vehicle (OTV) high pressure fuel pump. The high speed, high load, and long bearing life requirements dictated selection of hydrostatic bearings as the logical candidate for this engine. Design and fabrication of a bearing tester to evaluate these cryogenic hydrostatic bearings was then conducted. Detailed analysis, evaluation of bearing materials, and design of the hydrostatic bearings were completed resulting in fabrication of Carbon P5N and Kentanium hydrostatic bearings. Rotordynamic analyses determined the exact bearing geometry chosen. Instrumentation was evaluated and data acquisition methods were determined for monitoring shaft motion up to speeds in excess of 200,000 RPM in a cryogenic atmosphere. Fabrication of all hardware was completed, but assembly and testing was conducted outside of this contract.

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Volume 1. Preliminary design study: AXAF x ray calibration spectrometers. Volume 2. Revised preliminary design study: AXAF x ray calibration spectrometers

The objective of this work was to provide a preliminary design concept for a Flux Monitor Spectrometer (FMS) for use at the X Ray Astrophysics Facility (XRAF) during High Resolution Mirror Assembly (HRMA) testing that met the requirements of SAO-AXAF-88-025 dated July 31, 1991. The calibration test team determined that the spectral resolution of the FMS had to be greater than or equal to twice that of all the AXAF spectrometers throughout the 0.1 to 10 KeV range of x-ray energies. Since this effectively doubled the resolution required by SAO-AXAF-88-025, a change order was approved by the Marshall Space Flight Center and given to Radiation Sciences to revise their study.

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NASA Space Engineering Research Center for utilization of local planetary resources

Because of a change in the NASA funding cycle, the present reporting period covers only the six months from March to September 1991. Nevertheless, remarkable progress was made in a number of areas, some of the most noteworthy of which are: (1) Engineering operation of a breadboard CO2 yields O2 demonstration plant that produced over 10 grams of oxygen per day during several runs of over 100 hours each with a single electrolytic cell. Complete automation of controls, monitoring of various inputs/outputs and critical internal variables, diagnostics, and emergency shutdown in an orderly manner were also included. Moreover, 4-cell and 16-cell units, capable of much higher rates of production, were assembled and tested. (2) Demonstration of a 200 percent increase in the carbothermal reduction of ilmenite through vapor deposition of carbon layers on particles of that material. (3) Demonstration of the deposition of strong iron films from carbonyl chemical vapor deposition, establishing the crucial role of additive gases in governing the process. (4) Discovery of an apparent 800 percent increase in the conversion rates of a modified ilmenite simulant in a plasma-augmented reactor, including direct enhancement by solar radiation absorption. (5) Proof that test specimens of lunar soil with small amounts of metallic additives, recrystallized at moderate temperatures, exhibit an improvement of several orders of magnitude in ductility/tensile strength. (6) Experiments establishing the feasibility of producing silicon-based polymers from indigenous lunar materials. (7) Application of CCD technology to the production of maps of TiO2 abundance, defining primary ilmenite deposits, on the disk of the full moon. (8) Attainment of a discovery rate of approximately 3 new near-Earth asteroids per month by Spacewatch, more than doubling the previous global rate. (9) Coordination of industry and university magma electrolysis investigations in a workshop designed to define remaining problem areas and propose critical experiments.

Ramohalli, Kumar↗

Walking robot: A design project for undergraduate students

The objective of the University of Maryland walking robot project was to design, analyze, assemble, and test an intelligent, mobile, and terrain-adaptive system. The robot incorporates existing technologies in novel ways. The legs emulate the walking path of a human by an innovative modification of a crank-and-rocker mechanism. The body consists of two tripod frames connected by a turning mechanism. The two sets of three legs are mounted so as to allow the robot to walk with stability in its own footsteps. The computer uses a modular hardware design and distributed processing. Dual-port RAM is used to allow communication between a supervisory personal computer and seven microcontrollers. The microcontrollers provide low-level control for the motors and relieve the processing burden on the PC.

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Microelectrode-based technology for the detection of low levels of bacteria

A microelectrode-based electrochemical detection method was used for quantitation of bacteria in water samples. The redox mediator, benzoquinone, was used to accept electrons from the bacterial metabolic pathway to create a flow of electrons by reducing the mediator. Electrochemical monitoring electrodes detected the reduced mediator as it diffused out of the cells and produced a small electrical current. By using a combination of microelectrodes and monitoring instrumentation, the cumulative current generated by a particular bacterial population could be monitored. Using commercially available components, an electrochemical detection system was assembled and tested to evaluate its potential as an emerging technology for rapid detection and quantitation of bacteria in water samples.

Rogers, Tom D.↗

High-temperature, high-pressure optical port for rocket engine applications

This paper discusses the design, fabrication, and test of a window assembly for instrumentation of liquid-fueled rocket engine hot gas systems. The window was designed to allow optical measurements of hot gas in the SSME fuel preburner and appears to be the first window designed for application in a rocket engine hot gas system. Such a window could allow the use of a number of remote optical measurement technologies including: Raman temperature and species concentration measurement, Raleigh temperature measurements, flame emission monitoring, flow mapping, laser-induced florescence, and hardware imaging during engine operation. The window assembly has been successfully tested to 8,000 psi at 1000 F and over 11,000 psi at room temperature. A computer stress analysis shows the window will withstand high temperature and cryogenic thermal shock.

Delcher, Ray↗

Experimental validation of optimization-based integrated controls-structures design methodology for flexible space structures

An optimization-based integrated design approach for flexible space structures is experimentally validated using three types of dissipative controllers, including static, dynamic, and LQG dissipative controllers. The nominal phase-0 of the controls structure interaction evolutional model (CEM) structure is redesigned to minimize the average control power required to maintain specified root-mean-square line-of-sight pointing error under persistent disturbances. The redesign structure, phase-1 CEM, was assembled and tested against phase-0 CEM. It is analytically and experimentally demonstrated that integrated controls-structures design is substantially superior to that obtained through the traditional sequential approach. The capability of a software design tool based on an automated design procedure in a unified environment for structural and control designs is demonstrated.

Maghami, Peiman G.↗

Mars oxygen production system design

This report summarizes the design and construction of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere has been assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer data acquisition and control instrumentation is continuing.

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Atmospheric and spectroscopic research in the far infrared

The University of Oregon (UO) has been a major participant in the development of far infrared spectroscopic research of the stratosphere for the purpose of understanding the ozone layer processes. The UO has had a 15-year collaboration with the Italian group of B. Carli, and have participated in the 1978/79 Sub-millimeter Infrared Balloon Experiment (SIBEX), in the Balloon Intercomparison Campaign, (BIC), in the Infrared Balloon Experiment (IBEX), and in the recently concluded Far Infrared Experiment for UARS Correlative Measurements (FIREX). Both IBEX and FIREX programs were conducted in collaboration with NASA Langley, and were designed as validation flights in support of the Upper Atmosphere Research Satellite (UARS) Program. The technique of atmospheric far infrared spectroscopy offers two important advantages. First, many chemically important species can be measured simultaneously and co-spatially in the atmosphere. Second, far infrared atmospheric spectra can be obtained in thermal emission without reference to the sun's position, enabling full diurnal and global coverage. Recent improvements in instrumentation, field measurements, and molecular concentration retrieval techniques are now making the far infrared a mature measurement technology. This work to date has largely focused on balloon-based studies, but the future efforts will focus also on satellite-based experiments. A program of research in the following general areas was proposed: Laboratory Pressure broadening coefficient studies; specialized detector system assembly and testing; and consultation and assistance with instrument and field support. The proposal was approved and a three-year research grant titled 'Atmospheric and Spectroscopic Research in the Far Infrared' was awarded. A summary of technical accomplishments attained during the grant period are presented.

Park, Kwangjai↗