Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The objective of the Phase II effort will be an affordable demonstrated full-scale design for a thermally stable multi-meter submillimeter reflector. The Phase I effort resulted in a design for a thermally stable reflector which by analysis should survive the launch environment and satisfy the as manufactured surface tolerance and on orbit thermal stability requirements for operation at 660 GHz, as in a CAMEO SMLS type mission. The Phase I effort motivates the Phase II effort to demonstrate with flight-like hardware the thermal stability of the design developed in Phase I. The Phase I study answered fundamental questions about the important parameters affecting the hygro-thermal stability of a reflector. In the Phase II, we plan to develop the technology required to realize the important parameters for thermal stability and then demonstrate the predicted thermal stability with a flight-like test article.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
This proposal describes an Application Coherency Manager that implements and manages the interdependencies of simulation, data, and platform information. It will also enforce a simulation configuration profile submission that includes the specification of the interdependency requirements. To describe these interdependences, a general-purpose language will serve as the basis for higher-level rules that are assembled using a higher-level graphical user interface. We propose to implement a graphical user interface that allows the user to manage and assemble rule-profiles. A rule profile would be created by assembling and parameterizing one or more low-level code modules. This user interface would then be able to save these profiles into a revision archive, perhaps alongside the applications and the data sources. These profiles could then be checked out, and used. Locking the version of such a profile would freeze it in a known state. Leaving it unlocked would allow it to evolve. The profiles themselves would likely be stored as XML-based documents that refer to the low-level data-source checker modules
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Advanced Materials Technology, Inc (AMTI) responds to the NASA solicitation S2 "Advanced Telescope Systems" under subtopic S2.05, "Optics Manufacturing and Metrology for Telescope Optical Surfaces". The proposed program is aimed at developing large, ultra-lightweight mirror substrate, including membrane optics for very large aperture space telescopes. The novel materials offer considerable weight and cost savings. In order to prevent significant figure error, mirror substrate materials should have very low (ideally zero) coefficient of thermal expansion (CTE), low coefficient of moisture expansion (CME), low cure shrinkage, low internal stresses, low outgassing, and high thermal and environmental stability. The ultimate goal of the proposed Phase I program is to develop thin mirror substrate materials that will meet the desired requirements. Once the feasibility of the proposed technology is demonstrated in Phase I, we shall scale-up the thin mirror substrate technology in a Phase II program to meet the NASA requirements.
Highly Efficient, Compact, Wavelength Converters for Pulsed and CW Laser Sources Used in Lidar-Based Remote Sensing and Ranging Systems Project
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
AdvR, Inc. proposes the development of a highly efficient, fiber pigtailed, waveguide-based UV frequency converter module. This UV module will be an important element in future NASA sponsored Doppler lidar and High Spectral Resolution Lidar (HSRL) aerosol missions. The key innovation is the use of dual-element periodically poled waveguides embedded in a nonlinear optical substrate. This innovation results in a vast improvement in the measurement capabilities of lidar systems by enabling the use of a single stabilized laser to both operate a high power transmitter and generate low power frequency tripled light for synchronous calibration and frequency locking of the Fabry Perot filter on the lidar receiver. To be used in a space-based system, the UV module must be rugged and must perform optimally in a radiation environment over the mission lifetime. To achieve this goal, the proposed dual-element structure will be packaged in a compact, robust fiber-pigtailed package which will readily lend itself to future space qualification for mechanical stability of the package and radiation damage resistance of the non-linear optical material.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
In Phase 1, CRG demonstrated the feasibility of a novel approach to prepare cyanate ester based elastomers. This approach polymerizes in-situ siloxane within a reactive elastomer precursor matrix in order to achieve an elastomeric material with highly tunable and desired mechanical properties. This methodology shows great potential in materials development for applications such as space deployable structures, space seals, and aeroshells. Using this methodology CRG was able to show that elastomeric cyanate ester materials having a vary broad range of thermal and mechanical properties could be formulated using a relatively small amount of CRG's synthesized monomers and other low-cost, commercially available components, such as low-cost, low molecular weight silicone materials. The cyanate ester elastomer materials exhibited excellent thermal stability, maintaining their elastomeric properties to temperatures below -100 C and as high as 300 C. The proposed Phase 2 effort will leverage Phase 1 results and CRG's other extensive R&D in elastomeric material technologies to bring the methodology to readiness for transition to operational use.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
NASA's next generation of x-ray observation missions require x-ray calorimeters with superior energy resolution. Semimetallic HgTe has already proven itself as an excellent soft x-ray absorber material due to its low heat capacity. Hg0.834Cd0.166Te was shown in Phase 1 to have a heat capacity superior to that of HgTe. Hence Hg0.834Cd0.166Te-based microcalorimeter arrays are expected to have an energy resolution superior to that of HgTe-based ones. We propose the growth of single crystal Hg0.834Cd0.166Te layers by molecular beam epitaxy on Si substrates. Mercury vacancies will be filled after growth to reduce the possibility of them acting as acceptors and introducing a significant electronic heat capacity. The samples will be characterized by x-ray diffraction to assess their structural quality and crystallinity, FTIR mapping to confirm the uniformity of their energy gaps and alloy compositions, Hall measurements to assess their electrical transport properties, etch pit density counts to determine dislocation densities, transmission electron microscopy to determine microscopic structural information, and heat capacity and thermalization efficiency measurements at mK temperatures. These assessments will further test their promise as high energy resolution quantum calorimeters and will help optimize material and processing parameters. The thermal property measurements will be performed on samples specially processed to remove some or all of the Si substrates and CdTe buffer layers. Finally, the development of a broadband infrared/mm wave reflective coating will be undertaken. The produced samples will be compatible with incorporation into microcalorimeter arrays for NASA missions.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
CU Aerospace and its University of Illinois teammate propose the design, sub-component fabrication and preliminary test of an UltraSail "Cubesat" 20 m2 solar sail spacecraft leading to a flight test in low Earth orbit. The complete flight test program consists of: preliminary design and sub-component tests; fabrication and assembly of a University of Illinois Cubesat spacecraft bus adapted to solar sail deployment; spaceflight qualification testing; and the flight test. The proposed innovation will demonstrate a scalable flight test in a 3 kg package of a high performance 200 m long solar sail plus two Cubesats to achieve a solar sail areal density of 5 gm/m2, and a large cost reduction factor for flight test of advanced solar sails. Successful development of the UltraSail solar sail will enable very high energy inner heliosphere and interstellar scientific missions with large scientific payloads. In addition, near-earth missions, such as Heliostorm for early warning of solar storms, will provide more warning margin as the solar sail performance is increased with UltraSail technology.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The combination of smart devices and embedded metadata and networked (wire and wireless) technologies present real opportunities for significant improvements in reliability, cost-benefits, and safety for remote testing, performance measurement, and facility management. Adding robust and autonomous network protocol for routing will further simplify testing installation process and increase test facility reliability. However, the realization of a practical autonomous facility test system requires the synthesis of several technologies. One must bring together knowledge in the fields of sensors, data processing, distributed systems, and networks. Mobitrum proposes to develop "an autonomous facility health-enabled test instrumentation" for characterization and measurement of ground test facilities. The proposed device includes: (1) facility health-enabled sensor, (2) signal conditioning and analog-to-digital (digital-to-analog) conversion, (3) microprocessor, (4) on-board memory (e.g., Flash or EEPROM) for metadata storage and executable software, and (5) embedded network interfaces to create a powerful, scalable, re-configurable, and reliable distributed test instrument. Autonomous facility health-enabled test instrumentation is built upon an open-system architecture with standardized protocol modules easily to interface with industry standards.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Planetary exploration missions, such as those planned by NASA and other space agencies over the next few decades, require advanced chemical and biological marker measurement technologies that will help answer fundamental questions about the composition of the Solar System and the possibility of past and present extraterrestrial life. Electrical/electrochemical array-based systems are highly suited for space and terrestrial applications because of their robustness, high-sensitivity, low-power requirement, miniaturization capability, and diverse transducer mechanisms which permit detection of a broad range of target analytes. Scribner Associates Inc. will leverage its expertise in measurement science, analytical instrumentation for arrays, and impedance spectroscopy to develop a prototype high measurement channel density array impedance analyzer for use with existing (e.g., Mars Oxidant Instrument) and future chemical and biological sensor arrays for planetary exploration. The proposed low mass instrument has hundreds of measurement channels for use with arrays with a large number of sensors. The analyzer is capable of conducting DC and swept-frequency AC impedance measurement. Successful development of the impedance array analyzer will facilitate multiple mission deployments with arrays tailored to specific mission objectives therefore ensuring efficient investment of NASA resources.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Water electrolyzer stacks are a key component of regenerative fuel cells, designed to replace batteries as a means of storing electric energy on the lunar surface. The design and demonstration of an innovative water electrolyzer cell is proposed. The cell design will be significantly smaller and lighter than previous aerospace electrolyzers designed and built by Giner Electrochemical Systems, LLC. The new cell will support high-efficiency electrolysis at pressures up to 2,000 psi. Test data will be used to calibrate electrolyzer performance models. These models will, in turn, be used to guide design decisions for regenerative fuel cells relative to the electrolyzer stack and maximum operating/gas-storage pressures of the regenerative fuel cell. A preliminary analysis of an advanced cell frame new thermoplastic material will be conducted to determine its suitability for use in water electrolyzers. Successful completion of the first phase will lead to the development of a demonstration stack in a second phase.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
We propose an initial architectural and preliminary hardware design study for a high-rate receiver capable of decoding modulation suites specified by CCSDS 413.0-G-1 April 2003 (www.ccsds.org) and new advanced modulation suites. We propose to detail a design which can provide a throughput of greater than 300 Mbits/sec and 7 bits/sample output.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Robots are expected to fulfill an important role in manned exploration operations. They will perform precursor missions to pre-position resources for manned missions. They will assist astronauts in site preparation, buildup, and maintenance of a lunar outpost. To support these roles, new forms of human-robot interaction are needed. Task-level commanding and predictive interaction are promising for tasks where time delay and limited bandwidth make tele-operations difficult. Supervised autonomy has potential to make better use of human resources by reducing the mission preparation time for routine tasks. But these new types of operations require human operators to support new types of tasks. TRACLabs proposes to develop a software framework that facilitates human-robot teaming. This software framework will provide tools for human supervisors to use when monitoring the performance and health of robots. The framework also will assist task coordination by applying operational protocols for information communication and allocation of control during remote distributed operations. This work is an innovative combination of technologies to support the new human tasks that arise when operating robots at different levels of autonomy. For performance monitoring, we propose to develop tools for users to define and adjust monitoring conditions, computations, and summaries in response to changing situations and missions. Additionally we will provide software to aid understanding of operational events and their relationship to underlying data. To support coordinating tasks, we propose to integrate our existing agent technology for role-based notification using communication protocols with new technology for authorizing the handover of robotic control. Phase II will produce a software framework for human-robot teaming.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The objective of this project is to develop a physics-based pneumatic hammer instability model that accurately predicts the stability of hydrostatic bearings operating in a turbulent, compressible fluid. In phase 2, the rig will be fabricated and assembled, design of experiment will be executed. The empirical data will be used to determine if a particular variable, or input parameter, was a contributor to pneumatic hammer instability. If not, the variable is eliminated. If the variable is determined to be a contributor, it is non-dimensionalized and included in the equations of motion to develop a physics-based stability criteria. The resulting criteria will then be validated using test data. If the criteria is not validated, a gap assessment will be completed and the process is repeated. Once the criteria is validated, it is implemented.
Lightweight High Temperature Beta Gamma Alloy/Process Development for Disk and Blade Applications Project
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The primary material and manufacturing limitations of gamma TiAl alloys include processing difficulties, requiring costly non-conventional processing requirements, and large lamellar grains, which reduces damage tolerance. We have developed a new class of TiAl-based alloys, called beta gamma, which would remove such barriers. Unlike existing gamma alloys, beta gamma alloys are designed such that the ductile b phase is adequate at elevated temperatures (for processing) but negligible at the anticipated use temperatures (for performance). The alloys also feature significant grain refinement and compositional homogeneity. This program is aimed to utilize such beneficial beta-phase distribution and microstructure features observed in small (0.7kg) samples into forged disks from medium size (25kg) ingots. The process-ability will be validated by employing a conventional forging process, and refined lamellar microstructures will be generated through usual alpha treatments. The significance of this innovation is that beta gamma alloy disks can not only be produced by conventional forging, but also show improvements in RT strength and ductility and may retain other attributes (density, creep and oxidation) of conventional gamma alloys.
Spectrally-Tunable Infrared Camera Based on Highly-Sensitive Quantum Well Infrared Photodetectors Project
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
We propose to develop a SPECTRALLY-TUNABLE INFRARED CAMERA based on quantum well infrared photodetector (QWIP) focal plane array (FPA) technology. This will build on the handheld QWIP camera we DELIVERED to NASA in Phase 1 which featured a 320x256 QWIP FPA with fixed spectral response, as proof of this novel sensor technology. Phase 2 will broaden spectral coverage (~ 6 - 12 microns), expand array format to 640x512 (for wider field-of-view), shrink pixel pitch (for higher image spatial resolution), and incorporate a cooled filter wheel with 6 to 8 spectral bands. We will integrate the FPA with dewar/cooler/electronics/optics and deliver the resulting wideband camera to NASA for spectroscopic/imaging studies in this spectral range
Transmission and Distribution of Photosynthetically Active Radiation (PAR) for Biomass Production in Exploration Missions [7226-270] Project
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Physical Sciences Inc. (PSI) proposes to develop a plant lighting system which collects, transmits and distributes photosynthetically active radiation (PAR) for biomass production in planetary and transit missions. In this system, solar light or electric lamp light is collected by reflector optics and focused at the end of an optical fiber cable. The light is filtered by a selective wavelength filter to reject the non-PAR spectra to minimize heat generation within the plant growth chamber. The PAR spectra are transmitted to the plant growth chamber where the light is uniformly distributed over the plant growth area at optimum intensities. Key features of the proposed system are: (1) the PAR can be transmitted via a flexible optical fiber cable to plants away from the light source; (2) only the PAR will be transmitted to the plant, minimizing the thermal loading in the plant growth chamber, while the non-PAR spectra can be converted to electricity by means of low band-gap PV cells; (3) the low profile light diffuser makes more volume available for plant growth; and (4) the electric light source can be chosen for the best system efficiency and can be placed at the location best suited for thermal control.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
In situ wind and turbulence measurements play a key role in the support and validation of Earth science missions using spaced-based technology. NASA has been using Unmanned Aerial Vehicles (UAVs) in support of these Earth science missions, but the current UAVs do not have sensor packages to make science quality measurements of parameters including three-dimensional wind, turbulence, temperature, humidity, and pressure. AeroTech will develop 3-Dimensional Wind and Turbulence Measurement System for UAVs that is based on thermal anemometer technology and that will measure and resolve science quality wind vector and turbulence information throughout the flight envelope. The System will provide high quality data that will improve NASA's ability to validate, verify, and supplement spaced-based measurements taken during missions. Phase I will assess the capability of the thermal anemometer sensor portion of the system and finalize the system design. By the end of Phase II, the prototype system will have been developed, integrated into a UAV, and flight-tested.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Agiltron together with Prof. Michael Rubner's group at MIT is developing a new family of nanoporous, low refractive index coatings for next generation NASA UV anti-reflection (AR) application on large plastic optics. The initial application is intended for 2.5 m diameter PMMA Fresnel lenses which NASA anaticipates as part of the EUSO mission cosmic ray telescope. The new thin film technology combines MIT advances in nano-structured, self-assembled, low index multilayer structures with Agiltron's recently developed mist deposition process, a method for applying large area thin films at low temperature with precise layer thickness control. The proposed UV AR coatings consist of inter-connected oxide nanoparticles in the form of a 3D nanoporous network able to produce stable films with refractive indices as low as 1.1 and high transparency in the visible - UV. In Phase I of this program we successfully demonstrated AR coatings on PMMA substrates with UV reflectance less than 1% at 300-400 nm (compared to 5% for bare PMMA substrates). In Phase II, Agiltron intends to further develop the coatings to a higher technical readiness level (TRL) by improving the robustness and abrasion resistance of the films and engineering the deposition techniques to enable multilayer coatings of tuned refractive index (graded index) for broader band AR performance. By the end of Phase II, nanoporous films deposited by the mist process will possess high transparency, good environmental stability, and excellent abrasion resistance and mechanical integrity. The material can be applied conformally on large area glass and plastic substrates (polycarbonate, PMMA) using low annealing temperatures. Mist deposition is fundamentally inexpensive and may have commercial applications to the plastic optics industry for eyeglasses or cellphone camera lenses.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
ProtoInnovations, LLC proposes to develop a new type of planetary rover called a Lunar All-terrain Utility Vehicle ("Lunar ATV") to assist extra-vehicular activities in future lunar missions. The vehicle will operate unmanned or with an astronaut driving onboard. It will have a roughly 4 m2 footprint and be able to about twice as fast as an astronaut can walk on the Moon. The vehicle will feature four-wheel, all-terrain mobility with traction control. A multi-purpose tool interface and interchangeable cargo bays will support a variety of mission payloads. The Lunar ATV will be used for mission such as site preparation, emplacing beacons, equipment and commodity distribution, and sampling. It will also be useful for human/robot interaction experiments taking place at NASA research centers. The primary innovations of this effort are: ? A high-efficiency, long-life, lunar-relevant traction drive system ? A simplified steer / suspension chassis built for speeds over 1 m/s without sacrificing weight or maneuverability ? A multi-purpose tool interface for earthmoving, sampling, emplacing, etc. ? Traction control software to maximize performance in earthmoving and negotiating rough terrain ? CLARAty-compatible vehicle and tool interfaces to leverage NASA-developed teleoperation and autonomy software ProtoInnovations brings an impressive amount of experience to the task of designing the Lunar ATV. Working at Carnegie Mellon University, members of our team have developed robots to operate in some of the harshest environments on Earth: surveying Antarctic ice fields, traversing the Atacama Desert, exploring into an Alaskan volcano and mapping Chernobyl. In total, our robots have traveled roughly 500 km through some of the most difficult terrain on Earth. We've accomplished these tasks by building robots that are, above all else, controllable and reliable. Our team has experience building all of the subsystems involved in this project.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The overall objective of this research program is to improve the affordability, survivability, and service life of next generation aircraft through the use of ADAPT --- an integrated adaptive diagnostic and prognostic toolbox. The specific focus of the research effort is adaptive diagnostic and prognostic algorithms for systems with slowly-varying dynamics. Model-based machinery diagnostic and prognostic techniques depend upon high-quality mathematical models of the plant. Modeling uncertainties and errors decrease system sensitivity to faults and decrease the accuracy of failure prognoses. However, the behavior of many physical systems changes slowly over time as the system ages. These changes may be perfectly normal and not indicative of impending failures; however, if a static model is used, modeling errors may increase over time, which can adversely affect health monitoring system performance. Clearly, one method to address this problem is to employ a model that adapts to system changes over time. The risk in using data-driven models that learn online to support model-based diagnostics is that the models may "adapt" to a system failure, thus rendering it undetectable by the diagnostic algorithms. An inherent trade-off exists between accurately tracking normal variations in system dynamics and potentially obscuring slow-onset failures by adapting to failure precursors that would be evident using static models. The proposed ADAPT will feature an innovative new parameter estimation algorithm and new adaptive observer / Kalman filter techniques designed specifically for health monitoring. The research team of Barron Associates, Inc., the University of Virginia, and Lockheed Martin Aeronautics Company will demonstrate ADAPT using a high-fidelity electro-hydrostatic actuator simulation.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a resonant cavity. Such structure would exhibit an ultra-narrow, high-throughput band in the middle of a wide, low-transmission stop-band. During Phase I, through an extensive and detailed analysis, we performed a feasibility study to establish the operational characteristics and performance of the proposed tunable filter. Following this, we assembled and tested a breadboard and demonstrated filter tunability over 4 cm 1 with bandpass close to 0.25 cm-1, rejection level better than 23 dB, and acceptance angle of about 1 degree at 10.6 microns. The acquired data demonstrated our optimal approach for designing and constructing an ultra-narrow tunable optical bandpass filter. During Phase II, we will design, build, deliver to NASA, and perform field testing of a compact and robust prototype module of a 1" diameter narrowband filter with a tunability range of 10 cm-1, a bandpass range of 0.1 cm-1, background rejection of 30 dB, and transmittance better than 50%. A rugged and monolithic filter design will allow this instrument to be incorporated in air- or space-based platforms providing stable performance in harsh operating environments.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
This proposal addresses NASA's need for improved TPS materials. The incumbent CEV heatshield TPS for Orion's Block II lunar return is PICA, a low-density carbon fiber infiltrated with phenolic resin. Variants of PICA with improved thermomechanical properties would benefit future missions. This effort will create a series of "mid-density" ablative materials to fill the gap between low-density PICA and high-density Carbon-Carbon. Touchstone's carbon foam (CFOAM<SUP>REG</SUP>) has excellent thermomechanical properties, can be tailored to a range of densities (12 to 95 lbs/cu-ft), and has an open-cell structure allowing infiltration of high-temperature materials. Aspen Aerogels recently completed a Phase II subcontract with Touchstone demonstrating the capability of fully infiltrating CFOAM<SUP>REG</SUP> with phloroglucinol-furfuraldehyde carbon aerogels with chemistry similar to PICA's. Phase I will use carbon aerogel infiltration in CFOAM<SUP>REG</SUP> samples of 3 densities from 17 to 35 lb/cu-ft to be calcined at Touchstone to carbonize the aerogel, creating a mass of amorphous carbon within the pore structure. Filling CFOAM<SUP>REG</SUP> pores with pure carbon yields an inherent reduction in the TPS radiant heat transfer. Fully carbonized samples will be re-infiltrated with PICA phenolic resin, and sample characterization will be conducted via SEM to demonstrate the capability of producing small-scale Carbon Foam-Aerogel/Phenolic composites at various densities. At the end of Phase I, the TRL will be 3-4 and then 4-5 by the conclusion of Phase II.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
The main purpose of this NASA SBIR Phase II proposal is development of a novel type of high resolving power diffraction gratings based on volume Bragg gratings technology. The key innovation, which was used for creation of these gratings, is based on patented technology of production of high efficiency volume diffractive elements in photo-thermo-refractive (PTR) glass on which OptiGrate has an exclusive license from the University of Central Florida. The significance of the innovation is that volume diffractive gratings in PTR glass have diffraction efficiency more than 95% and resolving power up to 20,000 in spectral range from 400 to 2700 nm. These gratings have 25 mm-long standard aperture with possibility to increase it up to 50 mm with the spectral resolution less than 50 pm. This, to the best of our knowledge, exceeds parameters of all comparable gratings worldwide. Moreover, as a result of Phase I project performance, a combination of high resolution Bragg grating with Fabri-Perot etalon provides additional increasing of spectral selectivity and enables the further increasing of spectral resolution power. This approach will be used for development of narrow band filters for detection of O2 (766 nm), H2O (935 nm), CO2 (1571 nm) and CH4 (1650 nm) with spectral width well below 1 nm (100 ? 200 pm), aperture 25 mm, throughput exceeding 90% in both reflecting and transmitting geometries. An additional task in Phase II would be a development of a scanning technology within a narrow line about 100 pm with resolution in the range from 1 to 10 pm. Aperture 25 mm, selected radiation should be focused to a photoreceiver of about 200 um.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
Space-based interferometry missions have the potential to revolutionize imaging and astrometry, providing observations of unprecedented accuracy. Realizing the full potential of these interferometers poses significant technological challenges, including the efficient maneuvering of multiple collectors to various baselines; regulating the path-length of science light from the collecting telescopes to the combining instrument with nanometer accuracy, despite the presence of vibration; and demonstrating through hardware-in-the-loop simulation that spacecraft sub-systems can be coordinated to perform such challenging observations in a precise, efficient, and robust manner. We propose the Synthetic Imaging Maneuver Optimization (SIMO) program to develop a methodology, calibrated through hardware-in-the-loop testing using the SPHERES testbed, to optimize spacecraft maneuvers to more efficiently synthesize images for missions such as Stellar Imager. Time and fuel-optimal maneuvers are only a part of the optimization problem. Selecting the maneuver waypoints (number and location) determines the quality of the synthesized image. The number of spacecraft, the size of the sub-apertures, and the type of propulsion system used also impacts imaging rate, propellant mass, and mission cost. Capturing all of these mission aspects in an integrated mission optimization framework helps mission designers to select the most appropriate architecture for meeting the needs and constraints of future missions.
Published By National Aeronautics and Space Administration
Issued más de 9 años ago
Summary
Description
To meet the increasing power demand of today's spacecraft systems, an integrated power electronics system capable of interfacing, and simultaneously controlling, three power ports is proposed in this project. This new proposed power electronic architecture employs a single-stage power topology, thus allowing cost-effective control of power flow with improved efficiency, power density, and reliability. The project is developing an innovative, dc-dc converter which can effectively manage the interface of a source, a load, and an energy storage function within a single-stage, three-port topology. Modern advances in digital control, in conjunction with a novel power processing concept make this logical next-step possible. This unique topology and controller function together to realize three power processing paths which simultaneously utilize the power devices, allowing increased functionality while promising reduced losses and enhanced power densities. Control objectives include battery charge regulation, solar array peak power tracking, and/or load voltage regulation. The Phase I efforts completed the preliminary analysis and the proof-of- concept prototyping. A demonstration test was successfully conducted substantiating feasibility. Phase II will focus on system level control in order to demonstrate the concept in a relevant application with a solar array source, a lithium-Ion battery, and an electronic load bank as the bus.