One year life test of 1-1/2 inch image dissector Final report
Lifetime performance characteristics testing for image dissector tube under simulated loading conditions
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Analysis and evaluation of spacecraft battery life test data
Method for predicting ultimate cycle lives of spacecraft batteries from test data
Kent, J. R.↗
Cycle life test - Evaluation program for secondary spacecraft cells Annual report, period ending 14 Dec. 1969
Performance tests of electrochemical cells
Mains, D. E.↗
Status of life testing, stress testing, and failure analysis and corrective action
Service life/stress testing, failure analysis and corrective action from technical and cost positions
Bland, W. M., Jr.↗
Ion pump and leak life test
The fabrication and long term testing of a flight type ion pump and sintered inlet leak are described. These tests were conducted over a period of one year at an ion pump pressure of approximately 0.000001 torr. These long term tests were conducted to investigate aging of ion pumps and leaks under continuous use. Pumping speed and leak conductance, as well as other parameters, were measured on a weekly basis with ion pump start tests conducted on a monthly basis.
Ierokomos, N.↗
Life tests of small turbine-type flowmeters in liquid hydrogen
A total of 14 turbine-type flowmeters of 2.5- and 4-cm nominal size were operated for 100 or more hours at an average fluid speed in the unobstructed, upstream pipe of 20 m/s for the smaller meters and 9 m/s for the larger meters. Calibration shifts over a 6.1 range of calibration flow rates varied from 0.5 percent to 1 percent after 50 hr of operation. It is concluded that use of ball bearings with glass-filled Teflon retainers is most likely to produce minimal calibration shift with protracted use. Bearing replacement after 50 to 100 hr is recommended, depending on accuracy requirements, for meters used at the fluid speeds of the tests.
Hobart, H. F.↗
Fabrication and life testing of thermionic converters
An unfueled converter containing a chloride-fluoride duplex tungsten emitter of 4.78 eV vacuum work function was tested for 46,647 hours at an emitter temperature of 1973 K and an electrode power output of about 8 watts/sq cm. The test demonstrated the superior and stable performance of the (110) oriented tungsten emitter at high temperatures. Three 90 UC-10 ZrC(C/U = 1.04, tungsten additive = 4 wt %) fueled converters were fabricated and tested at an emitter temperature of 1873 K. Converter containing chloride-arc-cast duplex tungsten cladding showed temperature thermionic performance and slower rate of performance drop than converter containing chloride-fluoride duplex tungsten cladding. This is believed to be due to the superior fuel component diffusion resistance of the arc-cast tungsten substrate used in the fuel cladding. It was shown that a converter containing a carbide fueled chloride-arc-cast duplex tungsten emitter with an initial electrode power output of 6.80 watts/sq cm could still deliver an electrode power output of 6.16 watts/sq cm after 18,632 hours of operation at an emitter temperature of 1873 K.
Yang, L.↗
Long-duration life tests of slip ring capsule assemblies for inertial guidance platforms
Eight slip ring capsules, each having 80 or 100 circuits, were operated for time periods ranging from 14,300 hours to 24,700 hours. The test mode simulated the motion of gimbal axes of the Saturn inertial guidance the platform in an organic free nitrogen environment. Computer-compiled noise data (approximately 45,000 recordings) were graphed as a function of test time and position within the capsules and as extreme probability distributions. Greater than ninety-nine percent of the noise measurements for the capsules with sufficient lubrication were less than 10 milliohms. Capsules with glass dielectrics did not perform significantly differently than those with filled epoxy dielectrics. The initial wear mode of prow formation was followed by rider wear. After 10 to the 8th power wipes, ring wear depth did not exceed the surface finish and the radial rider wear depth was less than 13 microns.
Cole, S. R.↗
Long life testing of spare Mariner Venus '67 hardware
The faultless performance of the Mariner Venus '67 Power Conditioning Electronics (PCE) throughout six years of continuous operation in a simulated space environment is reported. Weekly functional tests supplemented by daily monitoring verified that the PCE equipment can perform to its intended functions for at least six years without apparent performance degradation. Performance throughout the test period was very stable, there are no circuit or redundancy improvements to be considered. When the equipment was examined after the test was completed, there was no evidence of any physical damage nor any difficulty in disconnecting the wiring connectors.
Silverman, S. W.↗
Microchannel plate life tests
The behavior of the gain of a microchannel plate (MCP) during operation of the latter at moderate output currents was investigated. The total charge per unit area, Q, extracted from the MCP is shown to be the relevant quantity for evaluating MCP performance. The shape of the gain versus Q curve provides information on the gain decay process. Long periods of stable gain, frequently exhibited by channeltrons, were not observed in the present experiment.
Sandel, B. R.↗
Traveling-wave tube reliability estimates, life tests, and space flight experience
Methods of estimating the reliability of TWT's are reviewed. Values for the mean time between failure of medium-power and high-power tubes were computed from data in the literature.
Lalli, V. R.↗
Life test results for an ensemble of CO2 lasers
The effects of cathode material, cathode operating temperature, anode configuration, window materials, and hydrogen additives on laser lifetime are determined. Internally oxidized copper and silber-copper alloy cathodes were tested. The cathode operating temperature was raised in some tubes through the use of thermal insulation. Lasers incorporating thermally insulated silver copper oxide cathodes clearly yielded the longest lifetimes-typically in excess of 22,000 hours. The use of platinum sheet versus platinum pin anodes had no observable effect on laser lifetime. Similarly, the choice of germanium, cadmium telluride, or zinc selenide as the optical window material appears to have no impact on lifetime.
Peruso, C. J.↗
Cycle life test
Statistical information concerning cell performance characteristics and limitations of secondary spacecraft cells is presented. Weaknesses in cell design as well as battery weaknesses encountered in various satellite programs are reported. Emphasis is placed on improving the reliability of space batteries.
Harkness, J. D.↗
Life testing of Mallory cells
Tests were performed to assess the effects of storage time, storage temperature, vibration, discharge rate and temperature, and capacity of high-rate, D size, lithium sulfur dioxide cells. Data from these tests are discussed.
Dugan, D.↗
Accelerated life testing effects on CMOS microcircuit characteristics
Modifications and additions to the present process of making CMOS microcircuits which are designed to provide protective layers on the chip to guard against moisture and contaminants were investigated. High and low temperature Si3N4 protective layers were tested on the CMOS microcircuits and no conclusive improvements in device reliability characteristics were evidenced.
Source record↗
Life test of a nickel cadmium battery with a protection/reconditioning circuit
Results are discussed for a Ni-Cd battery test over a period of 8 years, 2 months and 44,213 simulated low Earth orbits. The battery cells were protected against overdischarge and reversal at discharge rates up to 25 amperes (1.25C) by a battery protection and reconditioning circuit. The circuit performed flawlessly during the test, and proved its value, both as a battery reconditioner and a cell protection device. Battery cell failures are also discussed. The test demonstrated the viability of using Ni-Cd batteries at depth-of-discharge up to 25 percent for over 5 years in a low Earth orbit.
Lanier, J. R., Jr.↗
COMSAT Labs life test data for NiH2 cells
Data concerning a ten cell nickel hydrogen battery are presented. The plates are electrochemically impregnated using slurry plaque.
Stockel, J.↗
Cycle life test and failure model of nickel-hydrogen cells
Six ampere hour individual pressure vessel nickel hydrogen cells were charge/discharge cycled to failure. Failure as used here is defined to occur when the end of discharge voltage degraded to 0.9 volts. They were cycled under a low earth orbit cycle regime to a deep depth of discharge (80 percent of rated ampere hour capacity). Both cell designs were fabricated by the same manufacturer and represent current state of the art. A failure model was advanced which suggests both cell designs have inadequate volume tolerance characteristics. The limited existing data base at a deep depth of discharge (DOD) was expanded. Two cells of each design were cycled. One COMSAT cell failed at cycle 1712 and the other failed at cycle 1875. For the Air Force/Hughes cells, one cell failed at cycle 2250 and the other failed at cycle 2638. All cells, of both designs, failed due to low end of discharge voltage (0.9 volts). No cell failed due to electrical shorts. After cell failure, three different reconditioning tests (deep discharge, physical reorientation, and open circuit voltage stand) were conducted on all cells of each design. A fourth reconditioning test (electrolyte addition) was conducted on one cell of each design. In addition post cycle cell teardown and failure analysis were performed on the one cell of each design which did not have electrolyte added after failure.
Smithrick, J. J.↗