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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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Internal pressures of spacecraft compartments in time-varying pressure environment and including outgassing materials
Outgassing studies on polymers for cognizant spacecraft
Radiation induced outgassing with nuclear propelled aerospace vehicles
Outgassing apparatus and gas analysis data for modular nuclear vehicle
Test plan for LH2 insulation outgassing system
Outgassing pressure variation with time near perigee in satellite-borne pressure gages, using Langmuir model of surface adsorption
OGO-6 surface contamination by outgassing in space environment and decontamination by sputtering and desorption
Vacuum environment tests of microwave ovens and various freeze-dried foods cooked in oven to determine outgassing effects
Low outgassing polymeric materials for general service and communication satellite structures
Outgassing of multilayer insulation materials for use in cryogenic fuel tanks
Computer program for selected gases outgassing rates calculation, tabulating and plotting for NERVA fuel elements gas evaluation
Test results and data for achieving a low-outgassing polymer resin suitable for potting or a paint pigment are presented. The resin, prepared in 0.5-kg (1-lb) batches, is acceptable for spacecraft use; its weight loss is less than 0.5 percent, and the volatile condensable materials are less than 0.05 percent. The paint adheres to a primed fiber glass or aluminum substrate. Results of UV irradiation, electron and proton radiation, and thermal cycling are presented.
Methods for analyzing and characterizing outgassing contaminants from such materials as RTV 501 potting compound and S 13 G paint are presented. Fractional distillation of a gross distillate from RTV 501 rubber was carried out and the distilled fractions examined as to their ultraviolet and infrared spectra by gas liquid chromatography. A sensitive technique for structural analysis and molecular identification was found to consist of a gas chromatography-mass spectroscopy system, which was determined to be economically unfeasible at present.
A fluid polydimethylsiloxane resin having improved outgassing properties in the cured state is described. The fluid resin is obtained by pouring, to a height of up to about 2 inches a starting polydimethylsiloxane resin such as RTV-602 silicone resin and devolatilizing the starting resin at a temperature of about 125 to 150 C under a vacuum of at least 0.00001 torr.
Some of the test techniques used to evaluate the outgassing and contamination characteristics of prospective Apollo telescope mount (ATM) materials are reviewed. These include a screening test providing information on weight losses of materials, weights of their condensed outgas products, and white-light scattered by the condensed products. They also include an ultraviolet-region screening test and a comprehensive continuous in situ weight-loss test. Examples are presented of data obtained from each of the tests on various prospective ATM materials.
Spacecraft systems are baked-out under vacuum to remove occluded and adsorbed gases, solvents, water, plasticizer, and other materials acquired during their manufacture. Two bakeouts of solar panels were carried out. Quartz crystal microbalances installed in the vacuum chamber during the tests and held at 273 K (0 C) provided an ongoing measure of the panels' outgassing. From these data, the panels' material weight losses versus time were obtained. A comparison of the total weight loss expected during a relatively long bakeout with that accomplished during a reasonable period of time was used as a criteria for an acceptable duration of the bakeout in order to optimize cost effectiveness.
To investigate the importance to fusion devices of desorption of gas from walls or cryosurfaces under long time operation, preliminary mass spectrometric investigations were carried out on the NASA Lewis Bumpy Torus with a 0.1-2A discharge in D2 at a pressure of 4.0 to 6.6 x 0.00001 torr. During the initial tens of minutes of discharge operation large quantities of a component with mass number 28, believed to be nitrogen, were released. The decrease with time of the nitrogen density after its initial maximum, indicated a diffusion controlled outgassing from cryodeposits or wall material. When cold surfaces were allowed to warm up, large quantities of gas were released. The integrated amount of N2 was typically the same as that released during a discharge, while the amount of H2O was orders of magnitude larger.
In the investigation about 1000 mass spectra were taken with the aid of a quadrupole mass filter. Attention was given to the determination of the densities of impurities as functions of time during operation. Studies of (almost) steady-state spectra were conducted. Analyses of the gas released when cold surfaces were allowed to warm up were also carried out. The results of the investigation suggest that the outgassing is diffusion-controlled.