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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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Lightweight polyurethane foam assembled in panels is effective spacer material for construction of self-evacuating multilayer insulation panels for cryogenic liquid tanks. Spacer material separates radiation shields with barrier that minimizes conductive and convective heat transfer between shields.
Mechanism, made of 347 stainless steel, is attached to furnace port by bolted flange. Unit incorporates quick opening, high vacuum valve and associated fittings which provide connections to air lock evacuation and to inert gas supply for quenching specimen after it is withdrawn from furnace into air lock.
Prefabricated multilayered self-evacuating insulation panels using gas with low vapor pressure at cryogenic temperatures for application to storage of cryogens
Gas leak detection in evacuated systems using ultraviolet radiation probe
Self evacuating multilayer insulation system of aluminized Mylar and polyurethane foam for liquid hydrogen tanks
Multilayer insulation systems for cryogenics protection aboard spacecraft, considering mechanical properties, radiation shielding, component evacuation rate and outgassing
Multilayer insulation systems development and selection for cryogenics thermal protection on space vehicles, considering mechanical properties, radiation shielding, components, evacuation rate and outgassing
Small rocket engine tests were conducted for the purpose of obtaining pulse performance data to aid in preliminary design and evaluation of attitude control systems. Both monopropellant and hypergolic bipropellant engines of thrust levels from 1 to 100 lbs were tested. The performance data for the hypergolic propellant rockets are compared with theoretical performance calculated from idealized chamber filling and evacuation characteristics. Electromechanical delays in valve response and heat transfer characteristics were found to cause substantial deviation between theoretical and test performance. The theoretical analysis is modified to obtain a semi-empirical model for hypergolic propellant rockets which is demonstrated to be reasonably accurate for two different engine configurations over a considerable range of duty cycles.
A conceptual design was developed for an MLI system which will meet the design constraints of an ILRV used for 7- to 30-day missions. The ten tasks are briefly described: (1) material survey and procurement, material property tests, and selection of composites to be considered; (2) definition of environmental parameters and tooling requirements, and thermal and structural design verification test definition; (3) definition of tanks and associated hardware to be used, and definition of MLI concepts to be considered; (4) thermal analyses, including purge, evacuation, and reentry repressurization analyses; (5) structural analyses (6) thermal degradation tests of composite and structural tests of fastener; (7) selection of MLI materials and system; (8) definition of a conceptual MLI system design; (9) evaluation of nondestructive inspection techniques and definition of procedures for repair of damaged areas; and (10) preparation of preliminary specifications.
An evacuated high-resolution Czerny-Turner spectrograph, which is described in this paper, has been used to determine the strengths S and self-broadening parameters for lines in the R branch of the nu (sub 3) fundamental of carbon dioxide at 298 and at 207 K. The values of self-broadening parameters at 207 K are greater than those to be expected on the basis of a fixed collision cross section.
Silicone elastomer is placed in evacuating system, heated to 160 C and held at this temperature for 24 hours. Elastomer is then cooled to room temperature in vacuum, producing upgraded, low outgassing polymer of increased molecular weight.
Insulation system of test chamber will reach thermal equilibrium more quickly when it is gassy and least efficient than when evacuated and most efficient.
Multilayer insulations for long term cryogenic storage are described. The development effort resulted in an insulation concept using lightweight radiation shields, separated by low conductive Dacron fiber tufts. The insulation is usually referred to as Superfloc. The fiber tufts are arranged in a triangular pattern and stand about .040 in. above the radiation shield base. Thermal and structural evaluation of Superfloc indicated that this material is a strong candidate for the development of high performance thermal protection systems because of its high strength, purge gas evacuation capability during boost, its density control and easy application to a tank.
Small rocket engine tests were conducted for the purpose of obtaining pulse performance data to aid in preliminary design and evaluation of attitude control systems. Both monopropellant and hypergolic bipropellant engines of thrust levels from 5 to 445 N (1 to 100 lb) were tested. The performance data for the hypergolic propellant rockets are compared with theoretical performance calculated from idealized chamber filling and evacuation characteristics. Electromechanical delays in valve response and heat transfer characteristics were found to cause substantial deviation between theoretical performance and test performance. The theoretical analysis is modified to obtain a semiempirical model for hypergolic propellant rockets.
Hall mobility measurements on a number of single crystal silicon ribbons grown from graphite dies have shown some ribbons to have mobilities consistent with their resistivities. The behavior of other ribbons appears to be explained by the introduction of impurities of the opposite sign. Growth of a small single crystal silicon ribbon has been achieved from a beryllia dia. Residual internal stresses of the order of 7 to 18,000 psi have been determined to exist in some silicon ribbon, particularly those grown at rates in excess of 1 in./min. Growth experiments have continued toward definition of a configuration and parameters to provide a reasonable yield of single crystal ribbons. High vacuum outgassing of graphite dies and evacuation and backfilling of growth chambers have provided significant improvements in surface quality of ribbons grown from graphite dies.
An internal autonomous control system to either completely detumble a spacecraft or lessen the tumbling motions until the rescue craft arrives is discussed. Such a device would become active upon loss of control. The development of a movable mass control system to convert the tumbling motions of a disabled vehicle into simple spin is presented. A simple spin state would greatly facilitate crew evacuation and final despinning by an external means. The system moves a control mass, according to a selected control law, in the acceleration environment created by the tumbling motion. By moving the mass properly, the rotational kinetic energy of the system may be increased or decreased creating simple spin states about the minimum or maximum moment of inertia axis, respectively. The control system is designed for the latter case due to its associated stability in the presence of perturbing forces.
A method and apparatus for removing material and components such as the lens from an eye is described. High speed rotary cutting members at one end of a rod macerate the lens while an annular tubing disposed around the cutting members vibrates ultrasonically to coact with the cutting members in macerating the lens. At the same time, a liquid is supplied to the chamber behind the cornea of the eye. Spiral grooves extending along the rotating rod from the cutting members evacuate the liquid and the macerated material from the eye. An alternate embodiment of the apparatus includes a tube through which liquid is supplied to the operative site of the ultrasonically vibrating tube and the cutting members in the area of the lens.
The adaptation of the Self Evacuating Multilayer Insulation System to the space shuttle orbiter liquid hydrogen tanks was investigated. Small scale material screening tests and subscale panel tests demonstrated the potential of the insulation to withstand the anticipated 100 flight cycles. The composition of the material and the process for producing the finished insulation are described. Results of the various tests to determine the durability of the material are presented.