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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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Temperature and wind data are presented from 70 small meteorological sounding rockets launched from eight selected launch sites in the Western Hemisphere. Table 1 gives a complete listing of the launch sites involved and the altitude of temperature and wind observations successfully completed.
A .005 M solution of fluorescein in cyclohexanol was directionally solidified in a standard 10 x 10 x 45mm UV silica cuvette, using a bottom thermoelectric chilling device. Progress of the experiment was monitored by time lapse photography. During flight (SPAR I) the camera malfunctioned and only one quarter of the expected data were collected. Comparison of flight and ground specimens indicated that: (1) The dark green layer observed ahead of the solid-liquid interface which is most likely the solute-enriched zone, appears to be wider in the flight specimen; (2) Parasitic nucleation ahead of the solid-liquid interface in the flight sample led to an irregularly shaped interface, smaller grain size, equiaxed grain morphology and a larger average macroscopic growth rate; (3) The formation of equiaxed grains ahead of the solid-liquid interface in the flight specimen may be attributed to ordered islands within the liquid, which survived remelting because of the low degree of superheating (approximately equal to 1.5 C), did not settle because of reduced gravity and acted as nuclei during cooling.
Specimens of gas saturated carbon tetrabromide were directionally solidified in a transparent furnace using a gradient freeze technique. The original temperature gradient was 5 C/cm and the cooling rate was 40 C/h. Progress of the experiment was monitored photographically. Gas bubbles were generated at the advancing solidification front in each of the three specimens. The gas bubbles were observed to increase in size, coalesce, and eventually be grown into the solid specimen under low gravity conditions. No bubble detachment from the interface was observed. Identical specimens processed in the laboratory showed bubble nucleation, bubble growth, and eventual bubble detachment due to buoyancy forces. Examination of the specimens showed a significantly greater void content in the low gravity processed samples. The grain size was observed to be finer in the low gravity processed samples.
Observations made from the Viking 1 orbiter show very little water vapor in the Mars atmosphere in the southern hemisphere (0 to 3 precipitable micrometers) with a gradual increase across the equator to northern latitudes. Maximum amounts between 20 and 30 micrometers have been observed in the short period covered by the observations to date. The season, northern midsummer, corresponds to the beginning of the water vapor cycle in that hemisphere. A strong repetitive diurnal cycling between the solid and vapor phase is observed at a site to the east of the Tharsis Ridge at 10 deg north latitude; the vapor lies close to the martian surface and is most probably in saturation equilibrium with a surface haze or fog throughout much of the day.
The purpose of the experiment was objectively to measure sleep quantity and quality during prolonged space flight with the use of automatic equipment for onboard analyses of electroencephalographic (EEG) and electro-oculographic (EOG) activity and telemetry of sleep stage data.
A synthesis of organic matter from atmospheric carbon monoxide or carbon dioxide, or both, appears to take place in the surface material of Mars at a low rate. The synthesis appears to be thermolabile and to be inhibited by moisture.
Experiments were performed to study the effect of a low-gravity environment on the columnar-to-equiaxed transition (CET) during polycrystalline solidification. Solutions of H2O-30 wt% NH4Cl and H2O-37 wt% NH4Cl were solidified in semicylindrical molds with radial heat extraction. Both solutions were quenched from the same soak temperature (90 C); the respective superheat temperatures were, therefore, approximately 57 and 23 C. The lower superheat resulted in a completely columnar structure, and the higher superheat resulted in a 1/3 columnar - 2/3 equiaxed microstructure; these results were independent of the relationship between heat flow direction and gravity. Grain multiplication mechanisms observed were showering, thermal inversion driven convection cells, and compositionally induced density inversion driven convection cells.
There are no author-identified significant results in this report.
Samples of eutectic Bi/MnBi were directionally solidified during a low-g interval aboard the SPAR 6 flight and in a l-g environment under identical furnace velocity and thermal conditions. The Bi/MnBi eutectic is characterized by a regular rod eutectic whose morphology may be sensitive to thermo-solutal convection and by its components, MnBi, which is ferromagnetic. Morphological analyses on samples show statistically smaller interrod spacings and rod diameters with respect to samples grown under identical solidification furnace conditions in l-g. An adjustment between the interrod spacing, growth velocity, and total undercooling at the solidification interface is proposed. Morphological analyses on samples grown in l-g indicate little difference between results for different growth orientations with respect to the gravity vector. The magnetic properties are significantly affected, however, by the presence of a nonequilibrium magnetic phase and the nonequilibrium phase transforms to the equilibrium ferromagnetic phase during isothermal heat treatment.
A focused laser Doppler velocimeter system was developed for the measurement of atmospheric backscatter (beta) from aerosols at infrared wavelengths. The system was flight tested at several different locations and the results of these tests are summarized.
The effects of gravity on Bridgman-Stockbarger directional solidification of off-eutectic Bi/MnBi were studied in reduced gravity aboard the SPAR X flight and compared to normal-gravity investigations and previous eutectic Bi/MnBi SPAR flight experiments. The directional solidification of off-eutectic Bi/MnBi results in either a dendritic structure connected with local cooperative growth or a coupled low volume fraction faceted/non faceted aligned rod eutectic whose Mn macrosegregation, MnBi rod size, interrod spacing, and thermal and magnetic properties are sensitive functions of the solidification processing conditions. Two hypoeutectic and two hypereutectic samples were solidified during 605 sec of furnace travel, with an initial 265 sec low-gravity interval. Comparison Earth-gravity samples were solidified in the same furance assembly under identical processing conditions. Macrosegregation in the low-g samples was consistent with a metastable increase in Mn solubility in the Bi matrix, in partial agreement with previous Bi/MnBi SPAR findings of MnBi volume reduction.
Developed by Army engineer Raul Rodriguez at Camp Century in Greenland during the early 1960s, a Rodriguez Well uses heat exchangers and a submersible pump to create a cavity deep under a glacier’s surface and cycle the heated water up an ice shaft, siphoning a portion of the flow for consumption before sending the rest back down to the well. To evaluate the performance of a Rodriguez Well as one of multiple approaches for extracting water from massive ice deposits on Mars, a series of tests were performed at the Johnson Space Center (JSC) Energy Systems Test Area (ESTA) Facility under Martian equivalent environmental factors such as atmospheric and water surface pressure and density. These values were then used to create an energy balance model for a Martian Rodriguez Well, replacing the terrestrial environmental factors with the found Martian equivalents in a computer model published by the Cold Regions Research and Engineering Laboratory (CRREL). This report documents the test results and the subsequent findings from running the modified code.
As part of the Spring 2021 Engineering Student Trainee rotation with the National Aeronautics and Space Administration (NASA) through the Pathways program at Kennedy Space Center (KSC). I served under KSC’s Engineering directorate as a Pneumatics Engineering Intern for the Environmental and Life support Systems branch (NE-XF). During my Internship, I primarily supported the Exploration Ground Systems (EGS) program under the direct supervision of NE-XF Pneumatics Senior Engineer, Ruben Jaca, and NE-XF matrix supervisor, Stephen M. Anthony. I worked on the completion of a Pressure Vessel and Pressurized System (PVS) certification for a Payload Accommodation Subsystem (PAS) prototype. As part of the Pathways program, I was additionally exposed to various career and skill enhancement activities.
Verification experiment design for satellite-borne geodetic altimeter operating over seas
This report is the final experiment report for the TCSE and summarizes many years of hardware development and analyses. Also included are analyses presented in a number of TCSE papers that were prepared and given at scientific conferences including three LDEF Post-Retrieval Symposiums.
Collection of science experiments selected for solar thermionic flight test vehicle
Wave rotors, used in a gas turbine topping cycle, offer a potential route to higher specific power and lower specific fuel consumption. In order to exploit this potential properly, it is necessary to have some realistic means of calculating wave rotor performance, taking losses into account, so that wave rotors can be designed for good performance. This in turn requires a knowledge of the loss mechanisms. The experiment reported here was designed as a statistical experiment to identify the losses due to finite passage opening time, friction, and leakage. For simplicity, the experiment used a 3-port, flow divider, wave cycle, but the results should be applicable to other cycles. A 12 inch diameter rotor was used, with two different lengths, 9 inches and 18 inches, and two different passage widths, 0.25 inch and 0.54 inch, in order to vary friction and opening time. To vary leakage, moveable end-walls were provided so that the rotor to end-wall gap could be adjusted. The experiment is described, and the results are presented, together with a parametric fit to the data. The fit shows that there will be an optimum passage width for a given wave rotor, since, as the passage width increases, friction losses decrease, but opening-time losses increase, and vice-versa. Leakage losses can be made small at reasonable gap sizes.
There have been few reports on the behavior of software reliability models under controlled conditions. That is to say, most of the reported experience with the models is during the testing phase of actual projects, during which researchers have little or no control over the data with which they work. Give that failure data for actual projects can be noisy, distorted, and uncertain, reported procedures for determining model applicability may be incomplete.