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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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At least 1,603 records · Page 89
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Microgravity science experiment integration - When the PI and the PED differ

This paper addresses issues related to the integration of principal investigators (PIs) and payload-element developers (PEDs) for conducting effective microgravity experiments. The Crystal Growth Furnace (CGF) is used as an example to demonstrate the key issues related to the integration of a PI's sample into a facility run by a different organization. Attention is given to the typical preflight timeline, documentation required for experimental implementation, and hardware deliverables. A flow chart delineates the payload-integration process flow, and PI inputs required for an experiment include equipment and procedure definitions, detailed design and fabrication of the experiment-specific equipment, and specifications of the contract-end item. The present analysis is of interest to the coordination of effective microgravity experiments on the Space Station Freedom that incorporate PIs and PEDs from different organizations.

Baer-Peckham, M. S.↗
NASA NTRS1992

NASA's In-Space Technology Experiments Program

The objective of the In-Space Technology Experiments Program is to evaluate and validate innovative space technologies and to provide better knowledge of the effects of microgravity and the space environment. The history, organization, methodology, and current program characteristics are presented. Results of the tank pressure control experiment and the middeck zero-gravity dynamics experiment are described to demonstrate the types of technologies that have flown and the experimental results obtained from these low-cost space flight experiments.

Levine, J.↗
NASA NTRS1984

Spacecraft Control Laboratory Experiment: Status report

The Spacecraft Control Laboratory Experiment (SCOLE) will allow direct experimental comparison of competing control schemes for large flexible spacecraft structures. The experiment was designed to emulate the essential characteristics of a mathematical model design challenge which represents a Space Shuttle with a flexible mast and antenna attached. This experiment represents the third in a series of three flexible structure control experiments used by the Flight Dynamics and Control Division at LaRC. The key problem addressed by the facility is that flexible motion of the mast and antenna must be considered in the slewing and pointing control problems.

Williams, J. P.↗
NASA NTRS1992

Selected results for metals from LDEF experiment A0171

Metal specimens in disk type and ribbon configurations of interest to various programs at the Marshall Space Flight Center were exposed to the LEO environment for 5.8 years on Long Duration Exposure Facility (LDEF) Experiment A0171. Most of the metals flown were well heat sunk in the LDEF experiment tray which experienced benign temperatures, but a few metals were thermally isolated allowing them to experience greater thermal extremes. All metal specimens whose preflight weights were known showed a weight change as a result of exposure. Optical property and mass changes are attributed principally to atomic oxygen exposures. Silver and copper were grossly affected whereas tantalum, molybdenum, and several preoxidized alloys were the least affected. Metals contained in this experiment are shown. Results including mass, surface morphology, and optical property changes from selected evaluations of these metals are presented.

Whitaker, Ann F.↗
NASA NTRS1993

The continuing materials analysis of the thermal control surfaces experiment (S0069)

The long term effects of the natural and induced space environment on spacecraft surfaces are critically important to future spacecraft - including Space Station Freedom. The damaging constituents of this environment include thermal vacuum, solar ultraviolet radiation, atomic oxygen, particulate radiation, and the spacecraft induced environment. The behavior of materials and coatings in the space environment continues to be a limiting technology for spacecraft and experiments. The Thermal Control Surfaces Experiment (TCSE) was flown on the National Aeronautics and Space Administration (NASA) Long Duration Exposure Facility (LDEF) to study these environmental effects on surfaces-particularly on thermal control surfaces. The TCSE was a comprehensive experiment that combined in-space measurements with extensive pre- and post-flight analyses of thermal control surfaces to determine the effects of exposure to the low Earth orbit space environment. The TCSE is the first space experiment to directly measure the total hemispherical reflectance of thermal control surfaces in the same way they are routinely measured in the laboratory. The trend analyses of selected coatings performed as part of the continuing post-flight analysis of the TCSE are described. A brief description of the TCSE and its mission on LDEF are presented. There are several publications available that describe the TCSE, it's mission on LDEF, and initial results in greater detail. These are listed in the TCSE Bibliography.

Wilkes, Donald R.↗
NASA NTRS1993

Atomic oxygen effects on LDEF experiment AO171

The Solar Array Materials Passive Long Duration Exposure Facility (LDEF) Experiment (SAMPLE), AO171, contained in total approximately 100 materials and materials processes with a 300 specimen complement. With the exception of experiment solar cell and solar cell modules, all test specimens were weighed before flight, thus allowing an accurate determination of mass loss as a result of space exposure. Since almost all of the test specimens were thermal vacuum baked before flight, the mass loss sustained can be attributed principally to atomic oxygen attack. The atomic oxygen effects observed and measured in five classes of materials is documented. The atomic oxygen reactivity values generated for these materials are compared to those values derived for the same materials from exposures on short term shuttle flights. An assessment of the utility of predicting long term atomic oxygen effects from short term exposures is given. This experiment was located on Row 8 position A which allowed all experiment materials to be exposed to an atomic oxygen fluence of 6.93 x 10(exp 21) atoms/cm(sup 2) as a result of being positioned 38 degrees off the RAM direction.

Whitaker, Ann F.↗
NASA NTRS1992

The Photovoltaic Array Space Power plus Diagnostics (PASP Plus) Flight Experiment

An overview of the Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) flight experiment is presented in outline and graphic form. The goal of the experiment is to test a variety of photovoltaic cell and array technologies under various space environmental conditions. Experiment objectives, flight hardware, experiment control and diagnostic instrumentation, and illuminated thermal vacuum testing are addressed.

Piszczor, Michael F.↗
NASA NTRS1992

In-step Two-phase Flow (TPF) Thermal Control Experiment

The Two-Phase Flow Thermal Control Experiment is part of the NASA/OAST In-Space Technology Experiments (In-STEP) Program. The experiment is configured for the Hitchhiker Shuttle payload system and consists of a capillary pumped loop, heatpipe radiator, and two-phase flow heat exchanger. The flight experiment design approach, test plan, payload design, and test components are described in outline and graphic form.

Source record↗
NASA NTRS1992

NPB Cesium Space Experiment

Neutral Particle Beam (NPB) weapons systems are planned to perform the ballistic missile defense functions of nuclear weapon/decoy discrimination and warhead kill at appropriate energy levels and ion currents. Negatively charged ions are produced in a specialized ion source and focused into a high quality particle beam. NPB linear accelerators accelerate and steer the negatively charged ions using electric and magnetic fields. After acceleration and steering the neutralizer system strips away extra electrons from ions to form the electrically neutral particle beam. The neutral beam then travels through space to the target unaffected by the Earth's magnetic fields. Continuing technological advances have greatly reduced the size and weight of NPB accelerator systems. Ion current production has been enhanced by over 100 percent with the intermittent addition of cesium at the NPB ion source device. This increase in current is essential to attain the most light weight, compact NPB platforms and minimize expensive launch costs. Addition of cesium into the ion source has been identified by the NPB community as the highest priority risk reduction space experiment necessary prior to planned NPB accelerator experiments and later weapons systems. The NPB Cesium Space Experiment is planned to successfully demonstrate controlled cesium introduction and vaporization into a simulated ion source chamber. Microgravity effects on the cesium deposition will be studied as will the effects of small amounts of cesium on high voltage accelerator components that might be susceptible to electrical insulator break downs. The experiment design will simulate as closely as possible the environment, physical and operational characteristics of the actual NPB ion source.

Parsons, George M., III↗
NASA NTRS1993

LDEF Space Plasma-High Voltage Drainage Experiment post-flight results

The Space Plasma-High Voltage Drainage Experiment (SP-HVDE) was comprised of two identical experimental trays. With one tray located on the leading (ram facing, B10) edge and the other located on the trailing (wake facing, D4) edge of the Long Duration Exposure Facility (LDEF), it was possible to directly compare the effects of ram and wake spacecraft environments on charged dielectric materials. Six arrays of Kapton dielectric samples of 2 mil, 3 mil, and 5 mil thicknesses maintained at +/- 300, +/- 500, and +/- 1000 voltage bias formed the experimental matrix of each tray. In addition, each tray carried two solar cell strings, one biased at +300 volts and the other at -300 volts, to study current leakage from High Voltage Solar Arrays (HVSA). The SP-HVDE provides the first direct, long-term, in-flight measurements of average leakage current through dielectric materials under electric stress. The experiment also yields information on the long term stability of the bulk dielectric properties of such materials. Data and findings of the SP-HVDE are an extension of those from shorter term flight experiments such as the PIX-1 (Plasma Interaction Experiment) and PIX-2 and are therefore valuable in the design and evaluation of long-lived space systems with high voltage systems exposed to the low earth orbital environment. A summary of the SP-HVDE post flight analysis final report delivered to the LDEF Project Office under contract to the National Aeronautics and Space Administration is presented.

Yaung, J. Y.↗
NASA NTRS1993

The middeck 0-gravity dynamics experiment

The Middeck 0-Gravity Dynamics Experiment (MODE), flown onboard the Shuttle STS-48 Mission, consists of three major elements: the Experiment Support Module, a dynamics test bed providing computer experiment control, analog signal conditioning, power conditioning, an operator interface consisting of a keypad and display, experiment electrical and thermal control, and archival data storage: the Fluid Test Article assembly, used to investigate the dynamics of fluid-structure interaction in 0-gravity; and the Structural Test Article for investigating the open-loop dynamics of structures in 0-gravity. Deployable, erectable, and rotary modules were assembled to form three one- and two-dimensional structures, in which variations in bracing wire and rotary joint preload could be introduced. Change in linear modal parameters as well as the change in nonlinear nature of the response is examined. Trends in modal parameters are presented as a function of force amplitude, joint preload, and ambient gravity. An experimental study of the lateral slosh behavior of contained fluids is also presented. A comparison of the measured earth and space results identifies and highlights the effects of gravity on the linear and nonlinear slosh behavior of these fluids.

Crawley, Edward F.↗
NASA NTRS1993

JSC flight experiment recommendation in support of Space Station robotic operations

The man-tended configuration (MTC) of Space Station Freedom (SSF) provides a unique opportunity to move robotic systems from the laboratory into the mainstream space program. Restricted crew access due to the Shuttle's flight rate, as well as constrained on-orbit stay time, reduces the productivity of a facility dependent on astronauts to perform useful work. A natural tendency toward robotics to perform maintenance and routine tasks will be seen in efforts to increase SSF usefulness. This tendency will provide the foothold for deploying space robots. This paper outlines a flight experiment that will capitalize on the investment in robotic technology made by NASA over the past ten years. The flight experiment described herein provides the technology demonstration necessary for taking advantage of the expected opportunity at MTC. As a context to this flight experiment, a broader view of the strategy developed at the JSC is required. The JSC is building toward MTC by developing a ground-based SSF emulation funded jointly by internal funds, NASA/Code R, and NASA/Code M. The purpose of this ground-based Station is to provide a platform whereby technology originally developed at JPL, LaRC, and GSFC can be integrated into a near flight-like condition. For instance, the Automated Robotic Maintenance of Space Station (ARMSS) project integrates flat targets, surface inspection, and other JPL technologies into a Station analogy for evaluation. Also, ARMSS provides the experimental platform for the Capaciflector from GSPC to be evaluated for its usefulness in performing ORU change out or other tasks where proximity detection is required. The use and enhancement of these ground-based SSF models are planned for use through FY-93. The experimental data gathered from tests in these facilities will provide the basis for the technology content of the proposed flight experiment.

Berka, Reginald B.↗
NASA NTRS1993

Glovebox - an Excellent Environment for Microgravity Experiments

The use of the Spacelab Glovebox on the recent First United States Microgravity Laboratory (USML-1) mission and the success with which the facility accommodated a large number of microgravity experiments are discussed. Sixteen Materials Science experiments were developed and successfully operated during the first microgravity usage of this new glovebox in space. This facility has a closed working volume to safely contain loose particles and droplets that may be inadvertently freed in setting up or conducting the experiments. The facility also offers an excellent photographic laboratory for observing and recording science data. The USML-1 Spacelab Globebox was a highly successful project that provided the motivation to begin the development of an Orbiter Middeck Glovebox and also provided valuable experience in setting the requirements for the Space Station Freedom Microgravity Science Glovebox (MSG).

Chassay, Roger P.↗
NASA NTRS1992

Arcing rates for High Voltage Solar Arrays - Theory, experiment, and predictions

All solar arrays have biased surfaces that can be exposed to the space environment. It has been observed that when the array bias is less than a few hundred volts negative, then the exposed conductive surfaces may undergo arcing in the space plasma. A theory for arcing is developed on these high voltage solar arrays that ascribes the arcing to electric field runaway at the interface of the plasma, conductor, and solar cell dielectric. Experiments were conducted in the laboratory for the High Voltage Solar Array experiment that will fly on the Japanese Space Flyer Unit (SFU) in 1994. The theory was compared in detail with the experiment and shown to give a reasonable explanation for the data. The combined theory and ground experiments were then used to develop predictions for the SFU flight.

Hastings, Daniel E.↗
NASA NTRS1992

Design and development of a two-phase reservoir for the Capillary Pumped Loop (CAPL) Flight Experiment

The Capillary Pumped Loop (CAPL) Flight Experiment has undergone numerous design modifications to reflect recent changes in the thermal control system baselined for Earth Observation System (EOS) spacecraft. The experiment redesign has also allowed technological advances in two-phase fluid loop components to be incorporated. The experiment's reservoir is one of the components targeted for redesign. The design and development of a new reservoir for the CAPL Flight Experiment is discussed in this paper. A prototype reservoir is described, and a hydrodynamic analysis of its wick structure is included. Testing of the prototype reservoir is also discussed.

Wolf, David A.↗
NASA NTRS1992

Test results of the SHARE II Mid-deck Flight Experiment

The SHARE II (Space Station Advanced Radiator Experiment II) Mid-deck Experiment was flown on board the Space Shuttle (STS-37) from April 5 to 12, 1991. The purpose of the experiment was to demonstrate the operation of several design changes proposed for the NASA/Grumman SHARE II heat pipe as a result of the lessons learned during the first SHARE flight (STS-29) in March 1989. Two test articles flew during the mission. The first, the Bubble Management Test Article, was a Plexiglas model of the monogroove heat pipe. This test article was primarily used to evaluate the performance of two 0-g bubble management devices; the redesigned evaporator screen artery and the condenser bubble trap. The second, the Blended Manifold Priming Test Article, also constructed of Plexiglas, was used to demonstrate passive self-priming of a heat pipe blended manifold connecting three evaporator legs to a single condenser leg. Both test articles used a 50/50 mixture of ethanol and water as the working fluid. Overall, the experiment was highly successful, with all the major test objectives fulfilled, including blended manifold priming, condenser bubble trap operation, screen artery bubble ingestion, and elimination of hydraulic diameter mismatch.

Brown, Richard F.↗
NASA NTRS1985

Results of an observing system simulation experiment based on the proposed Windsat instrument

Two fraternal twin experiments were conducted as part of this study. A data impact experiment using real data (runs 1 and 2) was conducted to assess the impact that rawin wind observations have on both a 5-day assimilation and a single 5-day forecast generated at the end of each assimilation. An observing system simulation experiment (OSSE) using simulated observations (runs 3, 4, and 5) was conducted in order to first calibrate the OSSE results and second to use this calibration to estimate the 'real world' impact from the contribution of global 3-dimensional wind profiles generated from a space-based lidar system known as Windsat. Each of the three runs in the seond experiment were also 5-day assimilation runs with a 5-day forecast initialized from the last 6-hour update cycle of the assimilation. The data impact study revealed a consistent positive impact when rawin winds were added back into an otherwise complete FGGE data set. Both the 6-hour and 5-day forecasts were improved at all levels, in both hemispheres, and for both the wind and the geopotential height fields. Similar results were obtained from the two parallel simulation runs, 3 and 4. Together with the results from runs 1 and 2, calibration coefficients were generated so as to 'correct' the results determined from the addition of Windsat winds (run 5). The Windsat simulation showed a positive improvement in all cases studied. Even though only the tropics were enhanced with these wind observations, hemispheric rms errors were decreased in both the assimilation and 5-day forecast. The 6-hour forecasts of zonal wind from the assimilation run were improved by as much as 50 pct. on the average, and the single forecast showed an average improvement of near 30 pct. Even though these calibrated values are considered too optimistic, the skill of the forecast generated from this run extended the useful forecast period by 18-24 hours.

Arnold, Charles P., Jr.↗
NASA NTRS1993

Preliminary results of Mn partitioning experiments on Murchison analogues

Eucrites, howardites, and diogenites have Fe/Mn ratios between 30 and 45, while carbonaceous chondrites have much higher values between 90 and 150. Stolper (1977) first showed that basaltic achondrites could evolve from a precursor chondritic material through simple partial melting. These experiments indicated that chondritic material heated to temperatures near 1180 C with a fugacity of one log unit below the iron-wustite buffer curve, produced a eucritic mineralogy that contained olivine, pigeonite, plagioclase, spinel, glass, and metal. The partial melting experiments of Jurewicz et al. (1992) on an hydrous Murchison and Allende also showed that HED compositions were produceable at temperatures between 1130 C and 1325 C with fugacities below and above the iron-wustite buffer curve. However, the MnO abundances of Jurewicz were too low to produce suitable Fe/Mn ratios for HED's. We present below our results of partial melting experiments on Murchison analogues that involved temperatures between 1180 C and 1580 C and fugacities below the iron-wustite buffer curve. Our experiments resulted in MnO abundances nearly twice that of Jurewicz and indicate that the production of basaltic achondrite-like Fe/Mn ratios from precursor chondritic material are possible.

Boesenberg, Joseph S.↗