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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 289 records · Page 16

Preliminary greenhouse design for a Martian colony: Structural, solar collection, and light distribution systems

The design of a greenhouse that will be a component of a long-term habitat on Mars is presented. The greenhouse will be the primary food source for people stationed on Mars. The food will be grown in three identical underground modules, pressurized at 1 atm to allow a shirt-sleeve environment within the greenhouse. The underground location will support the structure, moderate the large environmental variations on the surface, and protect the crops from cosmic radiation. The design effort is concentrated on the outer structure and the lighting system for the greenhouse. The structure is inflatable and made of a Kevlar 49/Epoxy composite and a pipe-arched system that is corrugated to increase stiffness. This composite is pliable in an uncured state, which allows it to be efficiently packaged for transport. The lighting system consists of several flat-plate fiber optic solar collectors with dual-axis tracking systems that will continually track the sun. This design is modeled after the Himawari collector, which was designed by Dr. Kei Mori and is currently in use in Japan. The light will pass through Fresnel lenses that filter out undesirable wavelengths and send the light into the greenhouses by way of fiber optic cables. When the light arrives at the greenhouse, it is dispersed to the plants via a waveguide and diffuser system.

Source record↗

Inflatable Reflector For Solar Power And Radio Communication

Report proposes installation of lightweight inflatable reflector structure aboard spacecraft required to both derive power from sunlight and communicate with Earth by radio when apparent position of Earth is at manageably small angle from line of sight to Sun. Structure contains large-aperture paraboloidal reflector aimed toward Sun and concentrates sunlight onto photovoltaic power converter and acts as main reflector of spacecraft radio-communication system.

Sercel, Joel↗

Videogrammetric Model Deformation Measurement Technique for Wind Tunnel Applications

Videogrammetric measurement technique developments at NASA Langley were driven largely by the need to quantify model deformation at the National Transonic Facility (NTF). This paper summarizes recent wind tunnel applications and issues at the NTF and other NASA Langley facilities including the Transonic Dynamics Tunnel, 31-Inch Mach 10 Tunnel, 8-Ft high Temperature Tunnel, and the 20-Ft Vertical Spin Tunnel. In addition, several adaptations of wind tunnel techniques to non-wind tunnel applications are summarized. These applications include wing deformation measurements on vehicles in flight, determining aerodynamic loads based on optical elastic deformation measurements, measurements on ultra-lightweight and inflatable space structures, and the use of an object-to-image plane scaling technique to support NASA s Space Exploration program.

Barrows, Danny A.↗

A Review of Antenna Technologies for Future NASA Exploration Missions

NASA's plans for the manned exploration of the Moon and Mars will rely heavily on the development of a reliable communications infrastructure from planetary surface-to-surface, surface-to-orbit and back to Earth. Future missions will thus focus not only on gathering scientific data, but also on the formation of the communications network. In either case, unique requirements become imposed on the antenna technologies necessary to accomplish these tasks. For example, proximity (i.e., short distance) surface activity applications such as robotic rovers, human extravehicular activities (EVA), and probes will require small size, lightweight, low power, multi-functionality, and robustness for the antenna elements being considered. In contrast, trunk-line communications to a centralized habitat on the surface and back to Earth (e.g., relays, satellites, and landers) will necessitate high gain, low mass antennas such as novel inflatable/deployable antennas. Likewise, the plethora of low to high data rate services desired to guarantee the safety and quality of mission data for robotic and human exploration will place additional demands on the technology. Over the last few years, NASA Glenn Research Center has been heavily involved in the development and evaluation of candidate antenna technologies with the potential for meeting the aforementioned requirements. These technologies range from electrically small antennas to phased arrays and large inflatable antenna structures. A summary of these efforts will be discussed in this paper. NASA planned activities under the Exploration Vision as they pertain to the communications architecture for the Lunar and Martian scenarios will be discussed, with emphasis on the desirable qualities of potential antenna element designs for envisioned communications assets. Identified frequency allocations for the Lunar and Martian surfaces, as well as asset-specific data services will be described to develop a foundation for viable antenna technologies which might address these requirements and help guide future technology development decisions.

Miranda, Felix A.↗

NASA Tech Briefs, March 2010

Topics covered include: Software Tool Integrating Data Flow Diagrams and Petri Nets; Adaptive Nulling for Interferometric Detection of Planets; Reducing the Volume of NASA Earth-Science Data; Reception of Multiple Telemetry Signals via One Dish Antenna; Space-Qualified Traveling-Wave Tube; Smart Power Supply for Battery-Powered Systems; Parallel Processing of Broad-Band PPM Signals; Inexpensive Implementation of Many Strain Gauges; Constant-Differential-Pressure Two-Fluid Accumulator; Inflatable Tubular Structures Rigidized with Foams; Power Generator with Thermo-Differential Modules; Mechanical Extraction of Power From Ocean Currents and Tides; Nitrous Oxide/Paraffin Hybrid Rocket Engines; Optimized Li-Ion Electrolytes Containing Fluorinated Ester Co-Solvents; Probabilistic Multi-Factor Interaction Model for Complex Material Behavior; Foldable Instrumented Bits for Ultrasonic/Sonic Penetrators; Compact Rare Earth Emitter Hollow Cathode; High-Precision Shape Control of In-Space Deployable Large Membrane/Thin-Shell Reflectors; Rapid Active Sampling Package; Miniature Lightweight Ion Pump; Cryogenic Transport of High-Pressure-System Recharge Gas; Water-Vapor Raman Lidar System Reaches Higher Altitude; Compact Ku-Band T/R Module for High-Resolution Radar Imaging of Cold Land Processes; Wide-Field-of-View, High-Resolution, Stereoscopic Imager; Electrical Capacitance Volume Tomography with High-Contrast Dielectrics; Wavefront Control and Image Restoration with Less Computing; Polarization Imaging Apparatus; Stereoscopic Machine-Vision System Using Projected Circles; Metal Vapor Arcing Risk Assessment Tool; Performance Bounds on Two Concatenated, Interleaved Codes; Parameterizing Coefficients of a POD-Based Dynamical System; Confidence-Based Feature Acquisition; Algorithm for Lossless Compression of Calibrated Hyperspectral Imagery; Universal Decoder for PPM of any Order; Algorithm for Stabilizing a POD-Based Dynamical System; Mission Reliability Estimation for Repairable Robot Teams; Processing AIRS Scientific Data Through Level 3; Web-Based Requesting and Scheduling Use of Facilities; AutoGen Version 5.0; Time-Tag Generation Script; PPM Receiver Implemented in Software; Tropospheric Emission Spectrometer Product File Readers; Reporting Differences Between Spacecraft Sequence Files; Coordinating "Execute" Data for ISS and Space Shuttle; Database for Safety-Oriented Tracking of Chemicals; Apparatus for Cold, Pressurized Biogeochemical Experiments; Growing B Lymphocytes in a Three-Dimensional Culture System; Tissue-like 3D Assemblies of Human Broncho-Epithelial Cells; Isolation of Resistance-Bearing Microorganisms; Oscillating Cell Culture Bioreactor; and Liquid Cooling/Warming Garment.

Source record↗

A Review of Antenna Technologies for Future NASA Exploration Missions

NASA s plans for the manned exploration of the Moon and Mars will rely heavily on the development of a reliable communications infrastructure from planetary surface-to-surface, surface-to-orbit and back to Earth. Future missions will thus focus not only on gathering scientific data, but also on the formation of the communications network. In either case, unique requirements become imposed on the antenna technologies necessary to accomplish these tasks. For example, proximity (i.e., short distance) surface activity applications such as robotic rovers, human extravehicular activities (EVA), and probes will require small size, lightweight, low power, multi-functionality, and robustness for the antenna elements being considered. In contrast, trunk-line communications to a centralized habitat on the surface and back to Earth (e.g., relays, satellites, and landers) will necessitate high gain, low mass antennas such as novel inflatable/deployable antennas. Likewise, the plethora of low to high data rate services desired to guarantee the safety and quality of mission data for robotic and human exploration will place additional demands on the technology. Over the last few years, NASA Glenn Research Center has been heavily involved in the development and evaluation of candidate antenna technologies with the potential for meeting the aforementioned requirements. These technologies range from electrically small antennas to phased arrays and large inflatable antenna structures. A summary of these efforts will be discussed in this paper. NASA planned activities under the Exploration Vision as they pertain to the communications architecture for the Lunar and Martian scenarios will be discussed, with emphasis on the desirable qualities of potential antenna element designs for envisioned communications assets. Identified frequency allocations for the Lunar and Martian surfaces, as well as asset-specific data services will be described to develop a foundation for viable antenna technologies which might address these requirements and help guide future technology development decisions

Miranda, Felix A.↗

Accelerated Creep Testing of High Strength Aramid Webbing

A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

Jones, Thomas C.↗

E-Glider: Active Electrostatic Flight for Airless Body Exploration

The environment near the surface of asteroids, comets, and the Moon is electrically charged due to the Sun's photoelectric bombardment and lofting dust, which follows the Sun illumination as the body spins. Chargeddust is ever present, in the form of dusty plasma, even at high altitudes, following the solar illumination. If abody with high surface resistivity is exposed to the solar wind and solar radiation, sun-exposed areas andshadowed areas become differentially charged. The E-Glider (Electrostatic Glider) is an enabling capability foroperation at airless bodies, a solution applicable to many types of in-situ mission concepts, which leverages thenatural environment. With the E-Glider, we transform a problem (spacecraft charging) into an enablingtechnology, i.e. a new form of mobility in microgravity environments using new mechanisms and maneuveringbased on the interaction of the vehicle with the environment. Consequently, the vision of the E-Glider is toenable global scale airless body exploration with a vehicle that uses, instead of avoids, the local electricallycharged environment. This platform directly addresses the "All Access Mobility" Challenge, one of the NASA'sSpace Technology Grand Challenges. Exploration of comets, asteroids, moons and planetary bodies is limitedby mobility on those bodies. The lack of an atmosphere, the low gravity levels, and the unknown surface soilproperties pose a very difficult challenge for all forms of know locomotion at airless bodies. This E-Gliderlevitates by extending thin, charged, appendages, which are also articulated to direct the levitation force in themost convenient direction for propulsion and maneuvering. The charging is maintained through continuouscharge emission. It lands, wherever it is most convenient, by retracting the appendages or by firing a cold-gasthruster, or by deploying an anchor. The wings could be made of very thin Au-coated Mylar film, which areelectrostatically inflated, and would provide the lift due to electrostatic repulsion with the naturally chargedasteroid surface. Since the E-glider would follow the Sun's illumination, the solar panels on the vehicle wouldconstantly charge a battery. Further articulation at the root of the lateral strands or inflated membrane wings,would generate a component of lift depending on the articulation angle, hence a selective maneuveringcapability which, to all effects, would lead to electrostatic (rather than aerodynamic) flight. Preliminarycalculations indicate that a 1 kg mass can be electrostatically levitated in a microgravity field with a 2 mdiameter electrostatically inflated ribbon structure at 19kV, hence the need for a "balloon-like" system. Due tothe high density and the photo-electron sheath and associate small Debye length, significant power is requiredto levitate even a few kilograms. The power required is in the kilo-Watt range to maintain a constant chargelevel.

Electrostatic Flight↗

Creep Testing of Vectran Yarn

NASA and industry are developing inflatable space structures to provide deployable habitable volumes for future exploration missions in space and on the surface of the Moon and Mars. These structures must withstand the constant pressure loading of multi-year missions. These missions therefore require excellent creep resistance in the constituent cordage and webbings that provide the primary structure of the vessel, which is typically constructed using high-strength synthetic materials such as Vectran. Real-time and accelerated creep testing of Vectran webbings has been performed at NASA Langley Research Center (LaRC), however, acceptable correlation between the results of the two approaches has not yet been achieved. Given the additional complexity of the webbing architecture, creep testing at the yarn level is being studied to reduce the number of interacting properties and focus on the core creep behavior to see if better correlation can be achieved between real-time and accelerated tests. To achieve this objective a creep test stand that is able to support simultaneous testing of five Vectran yarns had been previously designed and built. The test stand utilizes two clamp-wrap grips to mount the yarn and has a 10:1 load ratio, via a lever-arm, henceforth, known as the lever-arm test stand. Real-time creep testing (without measuring the strain of the yarn) in this fixture produces yarn ruptures in the gauge section. However, a large scatter in the times to failure was seen in the results across multiple loading conditions. For example, a test at 70% of the ultimate tensile strength (UTS) was found to have specimens that failed within a matter of hours and others that took over 6 weeks to fail. Prior test data on Vectran webbings had indicated high variability in the material strength, leading to higher than average scatter in the creep testing of webbings, which could translate to the scatter in creep behavior at the yarn level as well. However, there was still the possibility that the lever-arm test stand was causing the high scatter in data; specifically, due to potential variability in the loading of each specimen. Therefore, an additional creep test setup was designed and built to attempt to determine if the large scatter in the results was due to inherent material properties, the lever-arm test stand, or both. The newly designed creep test stand, henceforth known as the conventional test stand, utilized the more typical method for creep testing which involved hanging a weight from the yarn with no additional load amplification. The conventional test stand was designed and fabricated in-house at LaRC. High speed cameras were used to validate that the specimens in the conventional test stand failed in the gauge section. Once it was determined that the conventional test stand would provide valid failures in the gauge section, creep tests on the Vectran yarns were run to compare to the lever-arm test stand results. Preliminary results for a 70% UTS creep test have some specimens failing within a number of hours and some failing in excess of 6 weeks. These results are similar to those seen on the lever-arm test stand, pointing towards a large variability inherent in the material. The poster/presentation will focus on the design, fabrication, and validation of the conventional test stand as well as present preliminary results comparing the creep data from the conventional and lever-arm test stands

creep testing↗

Creep Testing of Vectran Yarn

Presentation detailing the creep testing of Vectran yarn using two different test stands.

Inflatable Structures↗

Hybrid Inflatable Pressure Vessel

Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts. Figure 2 depicts selected aspects of the design of a vessel of this type with a toroidal configuration. The bladder serves as an impermeable layer to keep air within the pressure vessel and, for this purpose, is sealed to the central structural core. The web includes longitudinal and circumferential straps. To help maintain the proper shape upon inflation after storage, longitudinal and circumferential straps are indexed together at several of their intersections. Because the web is not required to provide a pressure seal and the bladder is not required to sustain structural loads, the bladder and the web can be optimized for their respective functions. Thus, the bladder can be sealed directly to the rigid core without having to include the web in the seal substructure, and the web can be designed for strength. The ends of the longitudinal straps are attached to the ends of the rigid structural core by means of clevises. Each clevis pin is surrounded by a roller, around which a longitudinal strap is wrapped to form a lap seam with itself. The roller is of a large diameter chosen to reduce bending of the fibers in the strap. The roller also serves to equalize the load in the portions of the strap on both sides of the clevis pin. The lap seam is formed near the clevis by use of a tapered diamond stitch: This stitch is designed specifically to allow fibers in the stitch and strap to relax under load in such a manner that the load becomes more nearly evenly distributed among all fibers in the stitch region. Thus, the tapered diamond stitch prevents load concentrations that could cause premature failure of the strap and thereby increases the strength of the strap/structural-core joint. The lap seam can be rated at >90 percent of the strength of the strap material.

Raboin, Jasen↗