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Happe, R. A.

Publications and source records attributed to Happe, R. A..

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Containerless preparation of advanced optical glasses: Experiment 77F095

Containerless processing of optical glasses was studied in preparation for space shuttle MEA flight experiments. Ground based investigation, experiment/hardware coordination activities and development of flight experiment and sample characterization plans were investigated. In the ground based investigation over 100 candidate glass materials for space processing were screened and promising compositions were identified. The system of Nb2O5-TiO2-CaO was found to be very rich with containerless glass compositions and as extensive number of the oxides combinations were tried resulting in a glass formation ternary phase diagram. The frequent occurrence of glass formation by containerless processing among the compositions for which no glass formations were previously reported indicated the possibility and an advantage of containerless processing in a terrestrial environment.

Happe, R. A.↗
NASA NTRS1981

Containerless processing of glass

Ground-based research on the containerless melting of glass and experiments performed during a flight on the SPAR 6 are described. Experiments leading to selection of the flight sample composition, a silica-modified gallia/calcia glass, and the preparation of a one quarter inch diameter flight sample are described. During the flight experiment, a sample of the glass was containerless melted and cooled to a clear glass in a single axis acoustic positioning apparatus. The functioning of the flight experimental hardware was evaluated. The evaluation of the sample is presented.

Happe, R. A.↗
NASA NTRS1974

Oxide glass processing in space

The experimental work performed thus far has resulted in the preparation of new glass compositions not reported heretofore in the open literature. Recent experiments which have resulted in the formation of 1/4-inch-diameter glass samples from two compositions, suggest that containerless melting and cooling as envisioned for space operations is of real technological significance. To date studies of space glasses have by choice been confined to oxide glasses only. It is felt that the applications for such glasses are more readily predictable than for the other materials, and that many of the principles that will evolve from a study of oxide glasses, which can be melted in air, permit a more direct approach to non-oxide materials in the future. The compositions being studied are all very simple in terms of traditional glass practices, none of them containing more than three major constituents. Future efforts should be concerned with more complex compositions, both to cover a broader range of optical properties and to enhance glass-forming tendencies.

Happe, R. A.↗
NASA NTRS1974

Experiments leading to the production of new glasses in space

A number of oxide compositions were prepared as ceramic rods which were melted in a CO2 laser beam while spinning. The molten droplets which were spun off the rods were allowed to free-fall cool. Many of the compositions selected were obtained as glasses of never-before-reported composition. It can be concluded that it is possible to obtain spherules of glasses from oxide compositions that have never before been obtained in the 'glassy state.' These initial experiments encourage future attempts to prepare larger sized glass boules by containerless melting and cooling in space or in appropriately simulated space.

Happe, R. A.↗
NASA NTRS1972

Experiments leading to the production of new glasses in space.

Report on an experimental program aimed at verifying proposed concepts of glassmaking in space from substances that to date have been observed only in a crystalline condition. A summary is presented on the results of experiments conducted by laser melting of ceramic rods of chosen composition and allowing the droplets ejected from the spinning rod to cool by free falling. This technique should permit an early evaluation of which compositions are most suitable for subsequent more expensive space experiments.

Happe, R. A.↗
NASA NTRS1972

Study of the production of unique new glasses

A number of high new oxide glasses have been prepared by a laser-spin melting technique where droplets are ejected from a molten mass. Techniques have been developed for measuring the optical properties of most of the new glasses so produced. A preliminary study of processing equipment for producing new glasses in a zero gravity environment onboard manned space laboratory is reported. Induction and laser melting emerge as preferred techniques for melting spheroids of new glass compositions in space. Sample calculations for power required to induction melt new glass compositions are presented. Cooling rate calculations show that radiation cooling of the high melting materials results in very short cooling times for 1/2 inch diameters to temperatures where the spheroids can be handled.

Happe, R. A.↗