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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 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Illustration of the use of modal assurance criterion to detect structural changes in an Orbiter test specimen

The analysis of empirical modal models of structural components using techniques based on the modal assurance criterion (MAC) defined by Ewins (1984) is discussed and demonstrated for the case of the Space Shuttle Orbiter aft bulkhead. Modal models of the bulkhead are constructed before and after environmental acoustic tests equivalent to 30 or 100 missions and compared (by computing their MACs) to detect significant structural changes; subdivision of the modal vector followed by computation of the MAC for each part is used to localize the changes. Numerical data demonstrating the usefulness of the MAC approach are presented in tables and diagrams.

West, Walter M.↗
NASA NTRS2017

Nuclear Cryogenic Propulsion Stage (NCPS) Fuel Element Testing in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

To satisfy the Nuclear Cryogenic Propulsion Stage (NCPS) testing milestone, a graphite composite fuel element using a uranium simulant was received from the Oakridge National Lab and tested in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) at various operating conditions. The nominal operating conditions required to satisfy the milestone consisted of running the fuel element for a few minutes at a temperature of at least 2000 K with flowing hydrogen. This milestone test was successfully accomplished without incident.

Emrich, William J., Jr.↗
NASA NTRS2017

Orion Ammonia Boiler System Preflight Test Preparations

The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

Ammonia↗
NASA NTRS1977

Reliability study of opto-coupled semiconductor devices and Light Emitting Diodes (LED)

Opto-coupler and light emitting diode (LED) failure mechanisms and associated activation energies were determind from the results of environmental and accelerated lift tests of over 2,400 devices. The evaluation program included LED phototransistor opto-couplers from three sources, LED photoamplifier opto-couplers from a single source, and discrete infrared emitting LEDs from two sources. Environmental tests to evaluate device mechanical integrity included power cycling (10,000 cycles), temperature cycling (500 cycles) and a sequence of monitored shock, monitored vibration and constant acceleration. Multiple temperature operating life tests were conducted at ambient temperatures between 25 C and 200 C. Opto-couplers were operated in both the 'on' and 'off' states during life testing.

Maurer, R. C.↗
NASA NTRS1983

Impact resistance of fiber composites: Energy absorbing mechanisms and environmental effects

Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

Chamis, C. C.↗
NASA NTRS1985

Impact resistance of fiber composites - Energy-absorbing mechanisms and environmental effects

Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

Chamis, C. C.↗
NASA NTRS1964

Rocket motor spin data

Flight tests of solid propellant rockets in dynamic spin or roll environments

SOLID PROPELLANT ROCKET ENGINE↗
NASA NTRS1974

Transition Reynolds number comparisons in several major transonic tunnels

Boundary-layer transition and test section environmental noise data were acquired in six major transonic wind tunnels as a part of a broader correlation of the effect of free-stream disturbances on transition Reynolds number. The data were taken at comparative test conditions on a sharp, smooth 10-deg included-angle cone. It was found that aerodynamic noise sources within the test section were the dominant sources of unsteadiness and that transition Reynolds number provided a good indicator for the resulting degradation in flow quality. Amplitudes, frequency composition, directivity, and origin of these disturbances are described.

Dougherty, N. S., Jr.↗
NASA NTRS1985

Space station environmental control and life support systems test bed program - An overview

The successful demonstration of the maturity of the regenerative Environmental Control and Life Support System (ECLSS) is an essential factor in the development of the Space Station. The present paper provides an overview of the Space Station ECLSS Test Bed Program, the mechanism by which the maturity of regenerative ECLSS technologies is demonstrated. Attention is given to the background regarding the ECLSS development, the purpose of the Space Station ECLSS Test Bed Program, the objectives of this program, the three facility elements of the ECLS Test Bed, the technical approach, the design support test phase, the testing of the Regenerative Life Support Equipment (RLSE) systems, advanced prototype testing, fallback testing, and the integrated test phase. The integrated test phase will provide the final demonstration of the regenerative ECLSS technology maturity.

Behrend, A. F., Jr.↗
DOE OSTI2013

The R&D of NSLS-II Girder Profiling

A precise state-of-the-art vibrating wire technique will be adopted to achieve the challenging ±30 μm magnet-magnet positioning requirement in NSLS-II storage ring. However, girder profile variation after relocation will merge all the efforts of precise magnet alignment. Girder profiling, a 2-steps process including baseline establishment and restoration in tunnel which never been applied before in accelerator field, will be implemented to keep the girder profile between magnetic measurement room and tunnel as close as possible. Laser tracker is chosen as the main instrument. Tests in environmentally controlled room indicate that a repeatability accuracy of ±10 μm can be achieved by laser tracker in several days period and it has the resolution of better than ±5 μm if serving as an indicator. Simulations and tests prove that an accuracy of better than ±10 μm can be achieved for both steps; therefore, the final magnet-magnet alignment accuracy can be better than ±20 μm. Most of the R&D activities will be presented.

36 MATERIALS SCIENCE↗
NASA NTRS1967

Microelectronics on ATS

Fabrication, packaging, and testing of microelectronic equipment for Applications Technology Satellite /ATS/ scientific experimental package

ELECTRONIC PACKAGING↗
DOE OSTI2016

In-air and pressurized water reactor environment fatigue experiments of 316 stainless steel to study the effect of environment on cyclic hardening

Argonne National Laboratory (ANL), under the sponsorship of Department of Energy’s Light Water Reactor Sustainability (LWRS) program, is trying to develop a mechanistic approach for more accurate life estimation of LWR components. In this context, ANL has conducted many fatigue experiments under different test and environment conditions on type 316 stainless steel (316SS) material which is widely used in the US reactors. Contrary to the conventional S~N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to develop an understanding of the material ageing issues more mechanistically (e.g. time dependent hardening and softening) under different test and environmental conditions. Better mechanistic understanding will help develop computer-based advanced modeling tools to better extrapolate stress-strain evolution of reactor components under multi-axial stress states and hence help predict their fatigue life more accurately. In this paper (part-I) the fatigue experiments under different test and environment conditions and related stress-strain results for 316 SS are discussed. In a second paper (part-II) the related evolutionary cyclic plasticity material modeling techniques and results are discussed.

Cyclic plasticity material modeling↗
NASA NTRSDate not supplied

Overview of Space Environmental Effects (SEE) Team Electrostatic Discharge (ESD) Testing

Electrostatic discharge (ESD) due to the radiation environment encountered during spaceflight missions is a serious risk that must be mitigated by careful testing and design considerations. The MSFC Space Environmental Effects (SEE) Team has world-class facilities for ESD testing along with decades of experience. The Team has recently conducted successful campaigns for several high-profile projects including Europa Clipper, Exploration Upper Stage, Lunar Gateway, Orion, Docking System, and Human Landing System. This presentation will give a brief overview of ESD causes, hazards, test methods and test deliverables.

Peter Bertone↗
NASA NTRS1964

Solar simulation testing of an earth satellite at Goddard Space Flight Center

The use of solar simulation to evaluate the thermal performance of a spacecraft is still relatively new and controversial. Reference 1 reports successful use of carbon arcs in testing the Telstar spacecraft. Additional information on the use of the carbon arc as a solar source should be useful in evaluating its effectiveness as a thermal design technique. At Goddard Space Flight Center carbon arcs have been used for achieving the solar simulation testing of spacecraft sized for the Delta and Scout boosters. This report presents data and experience from such testing, using the results from the flight backup Ariel II (UK-2/S-52) international satellite as an example.

ENVIRONMENTAL TESTING↗
NASA NTRS2008

LETS: Lunar Environments Test System

The Environmental Effects Branch (EM50) at the Marshall Space Flight Center has developed a unique capability within the agency, namely the Lunar Environment Test System (LETS). LETS is a cryo-pumped vacuum chamber facility capable of high vacuum (10-7 Torr). LETS is a cylindrical chamber, 30 in. (0.8 m) diameter by 48 in. (1.2 m) long thermally controlled vacuum system. The chamber is equipped with a full array of radiation sources including vacuum ultraviolet, electron, and proton radiation. The unique feature of LETS is that it contains a large lunar simulant bed (18 in. x 40 in. x 6 in.) holding 75 kg of JSC-1a simulant while operating at a vacuum of 10-7 Torr. This facility allows three applications: 1) to study the charging, levitation and migration of dust particles, 2) to simulate the radiation environment on the lunar surface, and 3) to electrically charge the lunar simulant enhancing the attraction and adhesion of dust particles to test articles more closely simulating the lunar surface dust environment. LETS has numerous diagnostic instruments including TREK electrostatic probes, residual gas analyzer (RGA), temperature controlled quartz crystal microbalance (TQCM), and particle imaging velocimeter (PIV). Finally, LETS uses continuous Labview data acquisition for computer monitoring and system control.

Vaughn, Jason A.↗