Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “unit testing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

SSME turbopump technology improvements via transient rotordynamic analysis

The rotordynamic behavior of the high pressure oxygen turbopump and high pressure fuel pump was analyzed for the Space Shuttle Main Engine. The identification of potential rotordynamic problem areas which might arise during operation of these units prior to their testing was accomplished. Alternative procedures for correcting potential rotordynamic problems should they occur were investigated. An adequate analytic and physical understanding of the turbopump rotordynamics was developed to improve the probability of a correct diagnosis of rotordynamic problems from test data. Transient rotordynamic models were developed for both turbopumps. The transient models model the hydrodynamic forces of the turbopump seals. A linear stability analysis was performed for the turbopump rotordynamics models, which included gyroscopic effects, seal forces, speed-dependent bearing characteristics, and internal rotor damping. Results are presented and discussed.

Childs, D. W.↗
NASA NTRS1975

Electronic delay ignition module for single bridgewire Apollo standard initiator

An engineering model and a qualification model of the EDIM were constructed and tested to Scout flight qualification criteria. The qualification model incorporated design improvements resulting from the engineering model tests. Compatibility with single bridgewire Apollo standard initiator (SBASI) was proven by test firing forty-five (45) SBASI's with worst case voltage and temperature conditions. The EDIM was successfully qualified for Scout flight application with no failures during testing of the qualification unit. Included is a method of implementing the EDIM into Scout vehicle hardware and the ground support equipment necessary to check out the system.

Ward, R. D.↗
NASA NTRS1977

Formulation of consumables management models: Test plan for the mission planning processor working model

The test plan and test procedures to be used in the verification and validation of the software being implemented in the mission planning processor working model program are documented. The mission planning processor is a user oriented tool for consumables management and is part of the total consumables subsystem management concept. An overview of the working model is presented. Execution of the test plan will comprehensively exercise the working model software. An overview of the test plan, including a testing schedule, is presented along with the test plan for the unit, module, and system levels. The criteria used to validate the working model results for each consumables subsystem is discussed.

Connelly, L. C.↗
NASA NTRS1978

Mini-BRU/BIPS 1300 watt (sub)e dynamic power conversion system development: Executive summary

The status of the Brayton Isotope Power System (BIPS) is summarized. A 1200 watt sub e ground development unit was built and tested in a 0.000010 torr vacuum environment. Peformance mapping and 1000 hours of proof of concept system testing were completed. Specific components, primarily turbocompressor/alternator and recuperator performed according to predictions, thus achieving the design goal of 25 percent net power conversion efficiency. The system was fabricated from superalloy (Hastelloy-X and Waspaloy) thus placing it entirely within current state-of-the-art technology. The system could be flyable in the early 1980's pending flight qualification.

Source record↗
NASA NTRS1978

Baseline performance of the GPU 3 Stirling engine

A 10 horsepower single-cylinder rhombic-drive Stirling engine was converted to a research configuration to obtain data for validation of Stirling computer simulations. The engine was originally built by General Motors Research Laboratories for the U.S. Army in 1965 as part of a 3 kW engine-generator set, designated the GHU 3 (Ground Power Unit). This report presents test results for a range of heater gas temperatures, mean compression-space pressures, and engine speeds with both helium and hydrogen as the working fluids. Also shown are initial data comparisons with computer simulation predictions.

Thieme, L. G.↗
NASA NTRS1980

Controller for solar-energy systems

Report describes operation and testing of computerized control unit for solar-heating and cooling systems. Unit includes electronics and 'plumbing'. Components are modular. Microprocessor with ROM and RAM operates fans, pumps, and valves, and retains selected data for 32 hours.

Hankins, J. D.↗
NASA NTRS1979

Ancillary data acquisition for LACIE

The design, implementation, and operational functions of the three phases of LACIE supported the data needs of all other elements of the project and required several types of data in addition to LANDSAT multispectral digital data. The nonelectronic data base consisted of statistical data, printed reports, periodicals, ground observed data received from intensive test sites and operational segments, and full-frame multispectral scanner CIR photographs. The following data were collected for the test sites in the United States and Canada: land use inventories, periodic crop observations, solar radiometer measurements, rainfall, and wheat yield for selected fields.

Spiers, B. E.↗
NASA NTRS1980

Accuracy of aircraft velocities from inertial navigation systems for application to airborne wind measurements

An experimental assessment was made of two commercially available inertial navigation systems (INS) with regard to their velocity measuring capability for use in wind, shear, and long-wavelength atmospheric turbulence research. The assessment was based on 52 sets of postflight measurements of velocity (error) during a "Schuler cycle" (84 minutes) while the INS was still operating but the airplane was motionless. Four INS units of one type and two units of another were tested over a period of 2 years after routine research flights similar to air-linetype operations of from 1 to 6 hours duration. The maximum postflight errors found for the 52 cases had a root mean square value of 2.82 m/sec with little or no correlation of error magnitude with flight duration. Using an INS for monitoring ground speed during landway in a predicted high wind shear situation could lead to landing speeds which are dangerously high or low.

Rhyne, R. H.↗
NASA NTRS1979

Altitude-age relationships of the lunar maria

Altitudes and relative ages of mare surface units were compared to test if a systematic correlation in height of lava eruption surfaces and age might reflect a corresponding increase in depth of the magma chamber with time; in addition the altitudes were studied to shed light on the time and place of warping of mare surfaces. The laser altimeter data from the Apollo missions and relative age data based on crater erosion models and crater counts were used for the study. The data were correlated by using the image data bank of the Lunar Geoscience Consortium. Results of the first part of the study are inconclusive as no systematic increase in height of lavas with time could be shown. The data of the second part of the study support the conclusion that mare surfaces may have warped throughout most of the time represented by sample ages from the Apollo missions, and that the lithosphere may have become strong enough to remain stable after the time of Apollo 12 samples around 3 b.y. ago.

Lucchitta, B. K.↗
NASA NTRS1979

Performance advantages of dynamically tuned gyroscopes in high accuracy spacecraft pointing and stabilization applications

The paper compares and describes the advantages of dry tuned gyros over floated gyros for space applications. Attention is given to describing the Teledyne SDG-5 gyro and the second-generation NASA Standard Dry Rotor Inertial Reference Unit (DRIRU II). Certain tests which were conducted to evaluate the SDG-5 and DRIRU II for specific mission requirements are outlined, and their results are compared with published test results on other gyro types. Performance advantages are highlighted.

Irvine, R.↗
NASA NTRS1983

Eddy-Current Damage Test for Carbon Composites

Nondestructive test method detects cracks in materials of low conductivity. Test setup includes eddycurrent unit with frequency of 2 to 20 MHz/ and storage oscilloscope. High frequency required to assure depth of penetration less than substrate thickness, to prevent thickness from influencing reading. Eddy-current analysis confirmed by visual inspection as damaged area was sectioned and evaluated.

Hamilton, A. B.↗
NASA NTRS1982

Automotive Stirling engine development program

Activities performed on Mod I engine testing and test results, progress in manufacturing, assembling and testing of a Mod I engine in the United States, P40 Stirling engine dynamometer and multifuels testing, analog/digital controls system testing, Stirling reference engine manufacturing and reduced size studies, components and subsystems, and computer code development are summarized.

Ernst, W.↗
NASA NTRS1982

EMU battery/SMM power tool characterization study

The power tool which will be used to replace the attitude control system in the SMM spacecraft was modified to operate from a self contained battery. The extravehicular mobility unit (EMU) battery was tested for the power tool application. The results are that the EMU battery is capable of operating the power tool within the pulse current range of 2.0 to 15.0 amperes and battery temperature range of -10 to 40 degrees Celsius.

Palandati, C.↗
NASA NTRS1982

An integrated regenerative air revitalization system for spacecraft

Progress towards development of an air revitalization system (ARS) for spacecraft breathable atmosphere regeneration is assessed, and a preliminary design for a one-person ARS is described. The ARS is considered a necessary component of any permanently manned orbital station, and studies have demonstrated that penalties for expendable air supplies justify an ARS for missions longer than 40 days. CO2 must be removed and O2 returned along with N2, which can be extracted from hydrazine, with the H2 component returning to the operation of the CO2 reduction subsystem. An experimental ARS (ARX-1) features a cabin humidity control unit, a CO2 concentrator, an air-cooled CO2 reduction reactor, an oxygen generator (electrolysis), the hydrazine N2 generator, and a water handling unit. A 120-day test demonstrated one-button startup and 480 hr operation in a normal mode.

Noyes, G. P.↗
NASA NTRS1983

Refrigeration for Cryogenic Sensors

Research in cryogenically cooled refrigerators is discussed. Low-power Stirling cryocoolers; spacecraft-borne long-life units; heat exchangers; performance tests; split-stirling, linear-resonant, cryogenic refrigerators; and computer models are among the topics discussed.

Gasser, M. G.↗
NASA NTRS1984

Constraints on future observing plans

Scheduling considerations in the deployment of transportable laser ranging systems (TLRS) in 1985 are discussed. The new TLRS units will be field tested in North America and Europe first before being sent to remote Mediterranean and South American sites. Six weeks' residence will be required for 600 hr of measurements at each site, although a second crew could bring the necessary time down to four weeks. The surveys are set for periods of the year with the greatest incidence of clear skies. Twelve sites have been selected in the Mediterranean area, although no weather data have been acquired. Site selections are constrained by the need for accessible roads, telephones, and the stability of the terrain. Details of the marker monument layouts are provided.

Coates, R. J.↗
NASA NTRS1985

GPS high dynamic receiver tracking demonstration results

Demonstration results are presented for a high dynamic GPS receiver. The receiver tested is a breadboard unit capable of tracking one simulated satellite signal in pseudorange and range rate. The receiver makes approximate maximum likelihood estimates of pseudorange and range rate each 20 ms, and tracks these observables using a third order filter with a time constant of 0.14 s. Carrier phase is not tracked, which eliminates the typical failure mode of loss of carrier lock associated with PLLs at high dynamics. The receiver tracks with pseudorange lag errors of under 0.06 m when subjected to simulated 50 g turns with 40 g/s peak jerk. Pseudorange errors due to receiver noise alone are approximately 0.6 m rms at a carrier power to noise spectral density ratio of 34 dB-Hz. The tracking threshold SNR is approximately 28 dB-Hz, which provides 12 dB margin relative to the 40 dB-Hz that occurs with minimum specified satellite signal strength, 3.5 dB system noise figure, and 0 dBi antenna gain.

Hurd, W. J.↗