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Results for “test effectiveness”

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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

The optimum cost-effective test time for redundant systems with specified reliability and confidence

This paper investigates the optimum test time to determine the number of redundant units needed to achieve high reliability with high confidence. Newly designed systems often have high initial failure rates which can be reduced by testing to find failure modes and remove them by redesign. To accurately estimate the required number of redundant units, the test time must be extended to accurately determine the failure rate. If the measured failure rate is used, there is a 50% chance that the actual hardware failure rate is higher. Using the measured failure rate gives only a 50% confidence that the failure rate and number of spares are not too low. After the test, given the measured failure rate and the desired reliability, the number of spares can be determined and the confidence in the reliability computed. Instead of accepting the reliability results of a fixed duration test, it is possible to set the requirements for both the redundant reliability and the confidence level and then compute the test time needed to minimize the total cost required to achieve these requirements. The confidence that the redundant reliability is not too low is increased by using a higher than measured failure rate to increase the number of spares. The higher number of spares increases cost. Longer test time reduces the variance in the failure rate and the increase in the number of spares, so that test cost increases and spares cost decreases. The total cost is the sum of the cost of the test time and the spares. The optimum test time produces the minimum total cost for the system failure rate, mission length, and required reliability and confidence level. Longer testing is justified by reduced cost. Some examples are given.

Harry W Jones↗
NASA NTRS2021

Linear Systems LSK389 and LSK489 Dual N-Channel JFET Amplifier Total Ionizing Dose and Single-Event Effects Test Report

The purpose of these tests was to characterize the susceptibility of the LSK389 and LSK489 Dual N-Channel JFET from Linear Systems to Single-Event Latchup due to heavy ions and to Total Ionizing Dose (TID) degradation at -65 °C and intermediate dose rate. The test was carried out to assess suitability of the amplifiers for the Ocean Color instrument (OCI) on the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) spacecraft.

Ray Ladbury↗
NASA NTRS2021

Single-Event Effect Test Report Analog Devices LTC1604AIG#90117 ADC

This study is to characterize the destructive single-event latchup (SEL) susceptibility of the LTC1604AIG#90117 (LTC1604) analog/digital converter (ADC). The device was monitored for SEL current events on the power supplies during exposure to a heavy ion beam at Lawrence Berkeley National Laboratory (LBNL) 88-inch Cyclotron. Testing was performed on September 11, 2021.

single-event latchup (SEL)↗
NASA NTRS2023

Single-Event Effect Testing of the Analog Devices AD8041ARZ Operational Amplifier

This study was undertaken to determine the single event transient distribution of a transimpedance amplifier configuration of the AD8041 Operational Amplifier. The AD8041 is made in a bipolar technology and the application of interest has a bipolar supply of ±5 V. The device was monitored for transient events on the output voltage during exposure to a heavy ion beam at Lawrence Berkeley National Laboratory’s (LBNL) 88-inch Cyclotron.

Matthew B. Joplin↗
NASA NTRS2022

AMD Radeon e9173 Low Power PCIE GPU Single Event Effects Test Report

The AMD Radeon Embedded e9170 Graphics Processing Unit (GPU), notably the e9173 Peripheral Component Interconnect Express (PCIE) variant, is of interest to Artemis generation programs with requirements for graphics rendering, compute, artificial intelligence (Ai) with a constraints-requiring piece-part procurement and power consumption of less than 50W. In addition to collecting heavy ion data on this device, a secondary purpose of this test campaign was to validate video capture hardware and software workflows used with GPU, microprocessor and system-on-chip device testing. Five (5) test patterns from the NEPP Processor Enclave (NPE) test suite were used with the e9173. The test patterns covered the operating system’s (OS) idle contribution towards the cross section, matrix math using tensorflow-rocm, two artificial intelligence models developed at NASA GSFC, and an industry standard GPU benchmarking application called Mesa GLXGears.

NASA Technical Memorandum (TM) test report for pos↗
NASA NTRS2023

Single-Event Effects Test Report Linux Operating System Configurations on TUL PYNQ-Z2

This study was undertaken to determine the single-event functional interrupt (SEFI) susceptibility on different Linux operating system configurations. The device-under-test (DUT) was the Xilinx Zynq-7020 SoC on the TUL PYNQ-Z2 board. The device was monitored for kernel panics or hangs, classified as SEFIs, to observe any differences in the SEFI cross sections between operating system configurations. The primary purpose of this experiment was to observe if the number of drivers installed in a Linux system affects its overall execution reliability.

Seth S Roffe↗
NASA NTRSDate not supplied

Solar Array System Combined Environmental Effects Tests: Gateway Power and Propulsion Element

The NASA Lunar Orbital Platform-Gateway (LOP-G), a vital component of NASA’s Artemis program, will serve as a multi-purpose outpost orbiting the Moon. A foundational component of LOP-G is the Power and Propulsion Element (PPE). The PPE is a high-power, +60-kilowatt solar electric propulsion spacecraft that will provide power, high-rate communications, attitude control, and orbital transfer capabilities for the Gateway. The solar array system will utilize 4-junction photovoltaic cell technology on a flexible substrate (roll-out solar array or ROSA) in combination with multiple diode assemblies to combine the power of the solar array strings. NASA’s Marshall Space Flight Center, together with the PPE developer, Maxar, are in the midst of completing a rigorous combined environments test campaign of 3 solar array coupons and 1 array blocking diode board coupon. The campaign includes Ultra-Violet Radiation, Charged Particle Radiation, Ion Erosion, Thermal Cycles, and Electrostatic Discharge tests. The environments are applied in 3 separate incremental stages reflecting the various mission phases: 460 days of Earth-to-Lunar Transit, with much of that time through the Van Allen Belts, 5-years in Lunar Near-Rectilinear Halo Orbit (NRHO) at the Moon, and finally 15-years in Lunar NRHO, which represents the end of the design life. This paper will report on the state of the testing for each coupon, and brief look at the array performance, including some unexpected sensitivities of array blocking diodes.

Gateway↗
NASA NTRS1980

The effect of test system misalignment in the dynamic tension test

The effects of test system misalignment are analyzed for dynamic tension tests using sheet type rectangular 1100-0 aluminum specimens. The strain rate is assumed constant only on the natural axis of the specimen even though the specimen is subjected to a constant strain rate test. The results include: (1) the lower the strain rate, the more significant the misalignment errors become; (2) misalignment errors of 50% are found at the extreme fibers of the specimen; (3) the strain rate variation in the cross section decreases with increasing plastic strain and vanishes at plastic strain equal to 0.8% at the midspan of the specimen; and (4) the neutral axis shifts toward the centerline of the specimen as the plastic strain increases, but it reaches a limit and does not completely move back to the centerline.

Wu, H. C.↗