Werner Sell equipment development
High temperature oven with fast-circulated hot air as possible equipment for spacecraft
Sell, W.↗
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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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Design considerations for microwave heating of space food
Reliability, weight, size, and power supplies as factors in designing microwave ovens for spacecraft
Stone, W.↗
A traverse gravimeter for the lunar surface
A semi-automatic, self-levelling lunar gravimeter was designed for the purpose of measuring gravity at predetermined stops along the route of a lunar rover vehicle to obtain a gravity profile. The traverse gravimeter is completely self-contained and is powered by an internal battery. The gravity sensor is a vibrating string accelerometer (VSA) which is enclosed in a precision oven. Gravity data are obtained by initiating a measurement. After the gravimeter has levelled, the VSA difference frequency is counted down and a gate is generated to enable a crystal-controlled clock to a BCD counter. The BCD counter stores the data which are a measurement of gravity. These data, displayed upon command by the astronaut, are transmitted by voice back to earth. It is expected that the accuracy of the gravimeter will be better than one milligal. Low power, light weight, reliability, and simplicity of operation are major considerations in the design of the gravimeter.
Mamon, G.↗
Development of self extinguishing Durette and/or Nomex fabric
A treatment was developed for Nomex or Durette fabric which renders it self-extinguishing in a 70% oxygen, 30% nitrogen atmosphere at 5 psia. The treatment does not degrade the physical and textile properties of the fabric excessively and does not outgas or have an objectional odor. The treatment is permanent and does not lose its fire protecting qualities after laundering. The treatment utilizes a mixture of formaldehyde, phosphorous acid, and tri-methyl phosphate in methanol. The cloth to be treated is held in a boiling solution of the above reagents for 24 hours, removed, air dried, and then heated to 120 C in a circulating air oven for 90 minutes. The treatment turns Nomex a pale yellow but does not have an appreciable effect on drape or hand. One inch wide strips of treated cloth failed in tension at 192 lbs, while untreated controls broke at 215 lbs. To remove any excess reagents, the cloth is processed in a home laundry through one wash and dry cycle without the use of any detergents. The thermal shrinkage of the treated material is 23% compared to a control of 40% for unwashed Stern Nomex HT 90-40.
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In situ analysis of planetary surfaces for organic materials.
Discussion of the possibility of investigating the physical, chemical, and biological state of other planets in the hope of encountering one or more that is presently in a state prior to or just after the evolution of living systems. It may then be possible to observe the chemistry at and near the surface, evaluate the sources of energy available, and search for the presence or absence of living systems, and their degree of similarity to terrestrial ones. The mass spectrometry technique is considered to be the most appropriate. A system consisting of a series of sample ovens which can be consecutively attached to the gas stream of a small gas chromatograph which is in turn connected to a mass spectrometer via a carrier gas separator has been developed for the exploration of the surface of Mars.
Biemann, K.↗
A traverse gravimeter for the lunar surface.
A semiautomatic, self-leveling lunar gravimeter has been designed for the purpose of measuring gravity at predetermined stops along the route of a Lunar Rover Vehicle to obtain a gravity profile. The Traverse Gravimeter is completely self-contained and is powered by an internal battery. The gravity sensor is a vibrating string accelerometer (VSA) which is enclosed in a precision oven. Gravity data are obtained by initiating a measurement. After the gravimeter has leveled, the VSA difference frequency is counted down and a gate is generated to enable a crystal-controlled clock to a BCD counter. The BCD counter stores the data which are a measurement of gravity. These data, displayed upon command by the astronaut, are transmitted by voice back to earth.
Mamon, G.↗
The effects of various cure cycles upon the viability of Bacillus subtillis var. niger spores within solid propellant.
Saturethane solid propellant was used in all tests. The spore inoculum was evenly distributed in the propellant. Samples weighing approximately 5 g were aseptically removed, placed into curing ovens, and exposed to cure temperatures. Initial tests were conducted at 82 and 93 C. Analysis of the obtained data indicated that the survivor curves were not linear. Exposure of the inoculated propellant samples to 93 C reduced the initial population to less than 0.01% in about 20 hours. At 82 C, approximately 168 hours were required for a similar reduction. Tests involving curing temperatures of 105 and 115 C were also conducted. It is pointed out that changes in the mechanism of spore inactivation due to chemical and physical changes in the propellant could account for the nonlinear survivor curves obtained.
Brewer, W. A.↗
Manufacture of large, lightweight parabolic antennas
Antenna was produced in segments. Parabole sections were built up as aluminum foil sandwich with core bonded by film adhesive; whole structure was oven-cured after assembly. Structure was assembled with special tool for splice-bonding segments into complete dish, and inflatable bladder to apply pressure at joints during cure.
Hooper, S. W.↗
Design and development of pressure and repressurization purge system for reusable space shuttle multilayer insulation system
The experimental determination of purge bag materials properties, development of purge bag manufacturing techniques, experimental evaluation of a subscale purge bag under simulated operating conditions and the experimental evaluation of the purge pin concept for MLI purging are discussed. The basic purge bag material, epoxy fiberglass bounded by skins of FEP Teflon, showed no significant permeability to helium flow under normal operating conditions. Purge bag small scale manufacturing tests were conducted to develop tooling and fabrication techniques for use in full scale bag manufacture. A purge bag material layup technique was developed whereby the two plys of epoxy fiberglass enclosed between skins of FEP Teflon are vacuum bag cured in an oven in a single operation. The material is cured on a tool with the shape of a purge bag half. Plastic tooling was selected for use in bag fabrication. A model purge bag 0.6 m in diameter was fabricated and subjected to a series of structural and environmental tests simulating various flight type environments. Pressure cycling tests at high (450 K) and low (200 K) temperature as well as acoustic loading tests were performed. The purge bag concept proved to be structurally sound and was used for the full scale bag detailed design model.
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Traverse gravimeter experiment
A semiautomatic self-leveling lunar gravimeter has been designed for the Apollo 17 mission. This traverse gravimeter, which is completely self-contained and powered by an internal battery, was used to measure gravity at predetermined stops along the route of the Lunar Rover Vehicle. The gravity sensor is a vibrating string accelerometer (VSA) enclosed in a temperature-controlled oven and gimballed leveling assembly. This instrument is capable of resolving gravity differences as small as 0.035 milligal (1 mgal = 0.001 cm/s) on the moon and yet also is able to measure the earth's gravity field of 980,000 milligals. Twenty-two measurements were taken on the moon during the Apollo 17 mission, during which the VSA temperature never varied more than 0.005 C. The flight results indicate an instrument accuracy of better than 2 mgal.
Buck, S. W.↗
Services provided in support of the planetary quarantine requirements of the National Aeronautics and Space Administration
The project to evaluate thermal sterilization for unmanned landers is reported. A temperature controlled oven with a nitrogen gas supply containing a known concentration of water is discussed. The studies show that bacillus lentus, bacillus brevis, bacillus coagulans, atypical bacillus spp., and actinomycete are isolated heat survivors. The thermal resistance is given for naturally occurring airborne bacterial spores collected on exposed teflon ribbons.
Favero, M. S.↗
Cleaning and activation of beryllium-copper electron multiplier dynodes.
Description of a cleaning and activation procedure followed in preparing beryllium-copper dynodes for electron multipliers used in sounding-rocket experiments to detect auroral electrons. The initial degreasing step involved a 5-min bath in trichloroethylene in an ultrasonic cleaner. This was followed by an ultrasonic rinse in methanol and by a two-step acid pickling treatment to remove the oxides. Additional rinsing in water and methanol was followed by activation in a stainless-steel RF induction oven.
Pongratz, M. B.↗
Thermally-stable, syntactic pyrrone foams
Foam formulations may be readily emplaced in honeycomb structures after heating to soft, doughlike consistency and forcing heated mixture into honeycomb cells. Final cure can be accomplished by simple oven cure, with no need for containment or restriction of foam formulation during cure.
Kimmel, B. G.↗
Development of autoclavable addition type polyimides
Two highly promising approaches to yield autoclavable addition-type polyimides were identified and evaluated in the program. Conditions were established for autoclave preparation of Hercules HMS graphite fiber reinforced composites in the temperature range of 473 K to 505 K under an applied pressure of 0.7 MN/m2 (100 psi) for time durations up to four hours. Upon oven postcure in air at 589 K, composite samples demonstrated high mechanical property retention at 561 K after isothermal aging in air for 1000 hours. Promise was shown for shorter term mechanical property retention at 589 K upon exposure in air at this temperature.
Jones, R. J.↗
Filament winding S-glass/polyimide resin composite processing studies
The work performed in selecting a TRW A-type polyimide resin that would be suitable for fabrication of filament wound reinforced plastic structures is described. Several different formulations were evaluated after which the P105AC formulation was selected as the most promising. Procedures then were developed for preparing P105AC/S-glass roving prepreg and for fabricating filament wound structural composites. Composites were fabricated and then tested in order to obtain tensile and shear strength information. Small, closed-end cylindrical pressure vessels then were fabricated using a stainless steel liner and end fittings with a P105AC/S-glass polar wound overwrap. These pressure vessels were cured in an air circulating oven without augmented pressure. It is concluded that the P105AC resin system is suitable for filament winding; that low void content, high strength composites are obtained by the filament winding process; and that augmented pressure is not required to effect the fabrication of filament wound P105AC composites.
Vaughan, R. W.↗
TRW A-type polyimide resin for filament winding
Studies were conducted to select a TRW A-type polyimide resin that would be suitable for fabrication of filament wound reinforced plastics structures. Several different formulations were evaluated after which the P105AC formulation was selected as the most promising. Procedures were developed for preparing P105AC/S-glass roving prepreg and for fabricating filament wound structural composites. Composites were fabricated and then tested in order to obtain tensile and shear strength information. Small, closed-end cylindrical pressure vessels then were fabricated using a stainless steel liner and end-fittings with a P105AC/S-glass polar-wound overwrap. These pressure vessels were cured in an air circulating oven without augmented pressure. It was concluded upon completion of this study that the P105AC resin system is suitable for filament winding; that low void content, high strength composites are obtained by the filament winding process; and that augmented pressure is not required to effect the fabrication of filament wound P105AC composites.
Vaughan, R. W.↗
Results of the long range position-determining system tests
The long range position-determining system (LRPDS) has been developed by the Corps of Engineers to provide the Field Army with a rapid and accurate positioning capability. The LRPDS consists of an airborne reference position set (RPS), up to 30 ground based positioning sets (PS), and a position computing central (PCC). The PCC calculates the position of each PS based on the range change information provided by each Set. The positions can be relayed back to the PS again via RPS. Each PS unit contains a double oven precise crystal oscillator. The RPS contains a Hewlett-Packard cesium beam standard. Frequency drifts and off-sets of the crystal oscillators are taken in account in the data reduction process. A field test program was initiated in November 1972. A total of 54 flights were made which included six flights for equipment testing and 48 flights utilizing the field test data reduction program. The four general types of PS layouts used were: short range; medium range; long range; tactical configuration. The overall RMS radial error of the unknown positions varied from about 2.3 meters for the short range to about 15 meters for the long range. The corresponding elevation RMS errors vary from about 12 meters to 37 meters.
Rhode, F. W.↗
An aneroid pressure sensor for constant-level balloons
The pressure sensor for the Tropical Wind Energy conversion and Reference Level Experiment (TWERLE) is described. Key design features of the sensor are: capacitive coupling, reference at midrange, up-down counting, passive oven, storage at flight pressure and prelaunch calibration. Sensor specifications are given which are based on the production results of 440 units. Drift, as estimated from simulated life tests, is 1 mb per 6 months. The overall weight of the sensor, including thermal package, is 180 g.
Levanon, N.↗