DESIGN, FABRICATION, AND TESTING OF A CESIUM ION ROCKET ENGINE - PHASE II.
Design, fabrication, and testing of a cesium ion rocket engine - phase ii
CESIUM ENGINE↗
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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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High temperature fatigue behavior of tungsten copper composites
The present study investigates the high-temperature fatigue behavior of a 9-v/o tungsten fiber-reinforced copper matrix composite. Load-controlled isothermal fatigue at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in-phase and out-of-phase between 260 and 560 C, were performed. The stress-strain response under all conditions displayed considerable inelasticity. Strain ratchetting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratchetting was always in a tensile direction, continuing until failure. The ratchetting during the out-of-phase TMF test shifted from a tensile to a compressive direction. For all cases, the fatigue lives were found to be controlled by the damage of the copper matrix. On a stress basis, TMF loading substantially reduced lives relative to isothermal cycling.
Verrilli, M. J.↗
Phase V of the single-breath washout test
A downward-deflecting phase V is often seen following the terminal rise (phase IV) in single-breath washout tests. To investigate the nature of phase V, experiments using simultaneous washouts of N2 and tracer boluses of Ar were performed on eight normal nonsmoking subjects aged 27-41 who exhibited a phase V. Phase V is found to occur in all subjects at expiratory flow rates between 0.1 and 2.0 l/sec shortly after expiration became flow limited. Volumes of both phases IV and V increase with increasing flow rate. The difference between the exhaled volumes at which flow became limited and phase V appeared is shown to be approximately equal to the anatomic dead space. Results support a model of lung emptying in a gravitational field in which flow limitation occurs first in the lower lung regions and then progresses toward the upper regions, causing phase IV. A decrease in the amount of flow from the upper relative to the lower regions after all regions have become flow limited then causes phase V.
Nichol, G. M.↗
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review
This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.
Source record↗
SITE project. Phase 1: Continuous data bit-error-rate testing
The Systems Integration, Test, and Evaluation (SITE) Project at NASA LeRC encompasses a number of research and technology areas of satellite communications systems. Phase 1 of this project established a complete satellite link simulator system. The evaluation of proof-of-concept microwave devices, radiofrequency (RF) and bit-error-rate (BER) testing of hardware, testing of remote airlinks, and other tests were performed as part of this first testing phase. This final report covers the test results produced in phase 1 of the SITE Project. The data presented include 20-GHz high-power-amplifier testing, 30-GHz low-noise-receiver testing, amplitude equalization, transponder baseline testing, switch matrix tests, and continuous-wave and modulated interference tests. The report also presents the methods used to measure the RF and BER performance of the complete system. Correlations of the RF and BER data are summarized to note the effects of the RF responses on the BER.
Fujikawa, Gene↗
Hot gas ingestion characteristics and flow visualization of a vectored thrust STOVL concept
A 9.2 percent scale short takeoff and vertical landing (STOVL) hot gas ingestion model was designed and built by McDonnell Douglas Corporation (MCAIR) and tested in the NASA Lewis Research Center 9- by 15-Foot Low Speed Wind Tunnel (LSWT). Hot gas ingestion, the entrainment of heated engine exhaust into the inlet flow field, is a key development issue for advanced short takeoff and vertical landing aircraft. The Phase 1 test program, conducted by NASA Lewis and McDonnell Douglas Corporation, evaluated the hot ingestion phenomena and control techniques and Phase 2 test program which was conducted by NASA Lewis are both reported. The Phase 2 program was conducted at exhaust nozzles temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/lift improvement devices which reduced the hot gas ingestion. The model support system had four degrees of freedom, heated high pressure air for nozzle flow, and a suction system exhaust for inlet flow. The headwind (freestream) velocity for Phase 1 was varied from 8 to 90 kn, with primary data taken in the 8 to 23 kn headwind velocity range. Phase 2 headwind velocity varied from 10 to 23 kn. Results of both Phase 1 and 2 are presented. A description of the model, facility, a new model support system, and a sheet laser illumination system are also provided. Results are presented over a range of main landing gear height (model height) above the ground plane at a 10 kn headwind velocity. The results contain the compressor face pressure and temperature distortions, total pressure recovery, compressor face temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane temperature and pressure distributions, model airframe heating, and the location of the ground flow separation. Results from the sheet laser flow visualization test are also shown.
Johns, Albert L.↗
Testing and Calibration of Phase Plates for JWST Optical Simulator
Three phase plates were designed to simulate the JWST segmented primary mirror wavefront at three on-orbit alignment stages: coarse phasing, intermediate phasing, and fine phasing. The purpose is to verify JWST's on-orbit wavefront sensing capability. Amongst the three stages, coarse alignment is defined to have piston error between adjacent segments being 30 m to 300 m, intermediate being 0.4 m to 10 m, and fine is below 0.4 m. The phase plates were made of fused silica, and were assembled in JWST Optical Simulator (OSIM). The piston difference was realized by the thickness difference of two adjacent segments. The two important parameters to phase plates are piston and wavefront errors. Dispersed Fringe Sensor (DFS) method was used for initial coarse piston evaluation, which is the emphasis of this paper. Point Diffraction Interferometer (PDI) is used for fine piston and wavefront error. In order to remove piston's 2 pi uncertainty with PDI, three laser wavelengths, 640nm, 660nm, and 780nm, are used for the measurement. The DHS test setup, analysis algorithm and results are presented. The phase plate design concept and its application (i.e. verifying the JWST on-orbit alignment algorithm) are described. The layout of JWST OSIM and the function of phase plates in OSIM are also addressed briefly.
Gong, Qian↗
Test Plan for the Technology Maturation of Supersonic Inflatable Aerodynamic Decelerators
Supersonic inflatable aerodynamic decelerators (IADs) are drag devices intended to be deployed at high Mach numbers. In the application considered here they assist in the descent and landing of spacecraft on Mars. Although promising, present IAD technology is not yet sufficiently mature for use in the near future. This paper describes a technology maturation plan for tension cone IADs using subscale test articles to reduce development costs. As envisioned, the proposed test plan includes three phases: wind tunnel tests (subsonic), unpowered high-altitude flight tests (transonic), and powered high-altitude tests (supersonic). This test plan is based on a building block approach in which successful completion of each phase adds to the understanding of the behavior of IADs and reduces the risk of the subsequent, more expensive phases. By properly scaling the IADs, test articles of the same size and nearly the same construction can be used for all three phases. The final phase is a dynamically scaled flight test with IAD deployment at the same Mach number as the full-scale vehicle on Mars. Two full-scale example cases are presented: one for a single-stage system (15 m dia. IAD to subsonic retropropulsion), and another for a two-stage system (10.5 m dia. IAD to subsonic parachute). Using scale factors of 0.333 and 0.476 yield subscale test IADs of 5 m dia. The dynamically scaled powered flight test starts at Mach 4 and an altitude of 33.5 km. Existing balloons and rocket motors are shown to be adequate to meet the required test conditions.
Kelly, Jenny R.↗
Response of a shroud-enclosed spacecraft to combined acoustic-vacuum environments
Tests were conducted in the launch phase simulator test facility, with the Orbiting Geophysical Observatory structural model and the Nimbus-type shroud being used as test items. Data are given for the acoustic vibratory response of the spacecraft as the ambient pressure external to the shroud was reduced. The results show that at most spacecraft locations, the reduction in ambient pressure causes a significant reduction in the vibration response. There are, however, certain locations on the spacecraft and spacecraft adapter trusses where the reduction in ambient pressure has no effect. The differences in vibration responses obtained in this test can be directly related to two important factors: (1) excitation path - the path through which the external acoustic energy flows (either the mechanical path through structural members, or the air path directly from shroud to spacecraft); and (2) noise reduction of the shroud as a function of ambient pressure. As the pressure external to the shroud is reduced, the vented shroud has a corresponding decrease in internal pressure. The change in internal air density means less energy will be transmitted via the air path.
Bruck, L. R.↗
Feasibility study of a low-energy gamma ray system for measuring quantity and flow rate of slush hydrogen
As part of a study to demonstrate the suitability of an X-ray or gamma ray probe for monitoring the quality and flow rate of slush hydrogen, mass attenuation coefficients for Cd-109 X- and gamma radiation in five chemical compounds were measured. The Ag-109 K rays were used for water and acetic acid, whereas E3 transition from the first excited state at 87.7 keV in Ag-109 provided the probe radiation for bromobenzene, alpha (exp 2) chloroisodurene, and cetyl bromide. Measurements were made for a single phase (gas, liquid, solid) as well as mixed phases (liquid plus solid) in all cases. It was shown that the mass attenuation coefficient for the selected radiations is independent of the phase of the test fluids or phase ratios in the case of mixed phase fluids. Described here are the procedure and the results for the five fluid systems investigated.
Singh, Jag J.↗
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.↗
Formal functional test designs with a test representation language
The application of the category-partition method to the test design phase of hardware, software, or system test development is discussed. The method provides a formal framework for reducing the total number of possible test cases to a minimum logical subset for effective testing. An automatic tool and a formal language were developed to implement the method and produce the specification of test cases.
Hops, J. M.↗
A Little Goes a Long Way
We were a team of five engineers responsible for the command and data systems used during experiment integration and testing of Spacelab payloads. For the most part, we performed component level testing for the experiments, the first phase of testing for Spacelab Program payloads. In the beginning, the members of my team didn't know what to think of me, but as time went by they realized that I was sincere. A relationship of trust developed. Since then, we've all moved on to other projects, but every now and then we run into each other and the bond that we have is still strong. Every good manager wants to do well by the people working on a project. One way to achieve this is simple: Pay attention to the environment in which your employees work. People warn you not to get mired in the details; they say you might miss the big picture. But sometimes it's the details that give you a better view of what the big picture is all about.
Jenkins, Kimberly R.↗
Design/Analysis of Metal/Composite Bonded Joints for Survivability at Cryogenic Temperatures
A major design and analysis challenge for the JWST ISM structure is the metal/composite bonded joints that will be required to survive down to an operational ultra-low temperature of 30K (-405 F). The initial and current baseline design for the plug-type joint consists of a titanium thin walled fitting (1-3mm thick) bonded to the interior surface of an M555/954-6 composite truss square tube with an axially stiff biased lay-up. Metallic fittings are required at various nodes of the truss structure to accommodate instrument and lift-point bolted interfaces. Analytical experience and design work done on metal/composite bonded joints at temperatures below liquid nitrogen are limited and important analysis tools, material properties, and failure criteria for composites at cryogenic temperatures are virtually nonexistent. Increasing the challenge is the difficulty in testing for these required tools and parameters at 30K. A preliminary finite element analysis shows that failure due to CTE mismatch between the biased composite and titanium or aluminum is likely. Failure is less likely with Invar, however an initial mass estimate of Invar fittings demonstrates that Invar is not an automatic alternative. In order to gain confidence in analyzing and designing the ISM joints, a comprehensive joint development testing program has been planned and is currently running. The test program is designed for the correlation of the analysis methodology, including tuning finite element model parameters, and developing a composite failure criterion for the effect of multi-axial composite stresses on the strength of a bonded joint at 30K. The testing program will also consider stress mitigation using compliant composite layers and potential strength degradation due to multiple thermal cycles. Not only will the finite element analysis be correlated to the test data, but the FEA will be used to guide the design of the test. The first phase of the test program has been completed and the preliminary analysis has been revisited based on the test data In this work, we present an overview of the test plan, results today, and resulting design improvements.
Bartoszyk, Andrew E.↗
Thermodynamic Vent System Applied as Propellant Delivery System for Air Force
Responding to a request from the Air Force, NASA Lewis Research Center engineers designed a combination pressure control and propellant delivery system based on thermodynamic vent system (TVS) technology. The Air Force is designing a new type of orbit transfer vehicle that uses energy from sunlight to both propel and power the vehicle. Because this vehicle uses propellant at a substantially slower rate than higher-energy rockets, it needed the Lewis-developed TVS technology for long-duration storage of cryogen propellants. Lewis engineers, in conjunction with industry partners, showed how this TVS technology could also be used to deliver propellant to the thruster. The Air Force has now begun the ground test demonstration phase. After successful completion of ground testing, the Air Force plans to use this technology in a space flight as early as 1999.
Source record↗
Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies
Biofilm formation in spacecraft wastewater systems is a complex and impactful problem. Biomass flowing in these wastewater systems can cause clogging, higher differential pressures, and flow restrictions impacting equipment reliability and function. To explore this issue, the Marshall Space Flight Center’s biofilm test stand was created and has been utilized to examine multiple biofilm mitigation techniques over a long duration test time. This paper is an update to a previous paper, ICES-2021-122, and will serve to discuss the modifications and enhancements to the biofilm test stand. While the previous configuration tested heat treatments and coatings, this phase of testing will examine differing materials, competing bacteria provided by an external bioreactor, a prototype phytoremediation unit, and additional testing with a nutrient filter. Configuration changes include the addition of float switches, adjustment of the drain assembly architecture and additional support hardware for the competing bacteria bioreactor and phytoremediation units.
ECLSS↗
Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies
Biofilm formation in spacecraft wastewater systems is a complex and impactful problem. Biomass flowing in these wastewater systems can cause clogging, higher differential pressures, and flow restrictions impacting equipment reliability and function. To explore this issue, the Marshall Space Flight Center’s biofilm test stand was created and has been utilized to examine multiple biofilm mitigation techniques over a long duration test time. This paper is an update to a previous paper, ICES-2021-122, and will serve to discuss the modifications and enhancements to the biofilm test stand. While the previous configuration tested heat treatments and coatings, this phase of testing will examine differing materials, competing bacteria provided by an external bioreactor, a prototype phytoremediation unit, and additional testing with a nutrient filter. Configuration changes include the addition of float switches, adjustment of the drain assembly architecture and additional support hardware for the competing bacteria bioreactor and phytoremediation units.
ECLSS↗
Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies
Biofilm formation in spacecraft wastewater systems is a complex and impactful problem. Biomass flowing in these wastewater systems can cause clogging, higher differential pressures, and flow restrictions impacting equipment reliability and function. To explore this issue, the Marshall Space Flight Center’s biofilm test stand was created and has been utilized to examine multiple biofilm mitigation techniques over a long duration test time. This paper is an update to a previous paper, ICES-2021-122, and will serve to discuss the modifications and enhancements to the biofilm test stand. While the previous configuration tested heat treatments and coatings, this phase of testing will examine differing materials, competing bacteria provided by an external bioreactor, a prototype phytoremediation unit, and additional testing with a nutrient filter. Configuration changes include the addition of float switches, adjustment of the drain assembly architecture and additional support hardware for the competing bacteria bioreactor and phytoremediation units.
ECLSS↗