- API data.nasa.gov | Last Updated 2018-09-07T17:39:46.000Z
<p>Future astrophysics missions require efficient, low-temperature cryocoolers to cool advanced instruments or serve as the upper stage cooler for sub-Kelvin refrigerators. Potential astrophysics missions include Lynx, the Origin Space Telescope, and the Superconducting Gravity Gradiometer. Cooling loads for these missions are up to 300 mW at temperatures of 4 to 10 K, with additional loads at higher temperatures for other subsystems. Due to low jitter requirements, a cryocooler with very low vibration is needed for many missions. In addition, a multi-stage cooler, capable of providing refrigeration at more than one temperature simultaneously, can provide the greatest system efficiency with the lowest mass. Turbo-Brayton cryocoolers have space heritage and are ideal for these missions due to negligible vibration emittance and high efficiency at low temperatures. The primary limitation in implementing Brayton cryocoolers at temperatures below 10 K has been the development of high efficiency turbines. On the proposed program, Creare plans to leverage recent developments in gas bearing technology and low-temperature alternators to realize a high-efficiency, low-temperature turbine. On the Phase I project, we will perform a proof-of-concept demonstration of the turbine technology at temperatures down to 4 K. On the Phase II project, we will build and demonstrate an advanced low-temperature turbine at temperatures of 4 to 10 K.</p>
- API data.nasa.gov | Last Updated 2018-09-07T17:42:46.000Z
There is a vast amount of SAR data that is challenging for scientists to use. We propose a variety of technologies in SAR processing that will accelerate the processing and the use of the science products. Specifically, we will: 1) Develop methods of computational acceleration by exploiting back projection methods on cloud-enabled GPU platforms to directly compute focused imagery in UTM (landsat grid). This will deliver SAR data to users as user-ready products, in a form that is most familiar to them from optical sensors and which has never been done before. It has been a major obstacle for scientists to adopt radar data. Once formed, the data can be accessed on standard GIS platforms. We could greatly reduce the processing complexity for users so they can concentrate on the science, and bring the products seamlessly into the 21st century tools that are rapidly evolving to handle the developing data explosion; 2) Develop python-based framework technologies at the user interface that support a more natural way for scientists to specify products and actions, thereby accelerating their ability to generate science results 3) Extend the ESTO-funded InSAR Scientific Computing Environment framework to uniformly treat polarimetric and interferometric time-series such as those that will be created by the NISAR mission using serialized product-based workflow techniques. There are several key challenges that need to be addressed in parallel: 1) speed and efficiency in handling very large multi-terabyte time-series imagery data files. This requires innovations in multi-scale (GPU, node, cluster, cloud) workflow control; 2) framework technologies that can support the varied algorithms that these data can support, from SAR focusing, interferometry, polarimetry, interferometric polarimetry, and time-series processing; framework technologies that can support heterogeneous, multi-sensor data types (point-clouds and raster) in time and space. NASA’s upcoming radar mission, NISAR, will benefit from this technology after its planned launch in 2021, but first the vast archive of all international missions such as the Sentinel-1 A/B data at the Alaska Satellite Facility can be exploited more fully.
Validation of the NSBRI Astronaut Cardiovascular Health and Risk Modification (ASTRO-CHARM) Integrated Cardiovascular Risk Calculatordata.nasa.gov | Last Updated 2018-09-05T23:04:16.000Z
In 2012, the National Space Biomedical Research Institute (NSBRI) supported the development of an integrated tool, termed the Astronaut Cardiovascular Health and Risk Modification (ASTRO-CHARM) Integrated Cardiovascular Risk Calculator. The initial version of this tool was delivered to NSBRI in February of 2014 and has already been implemented in spaceflight on an ad hoc basis. This project seeks to update and validate the ASTRO-CHARM calculator. <p></p> Specific Aim 1: To refine the ASTROCHARM tool using extended cardiovascular (CV) event data. Version 1 of the ASTROCHARM tool comprised 6782 subjects with a 159 CV events over a mean follow up of 7.5 years. Both the Dallas Heart Study (DHS) and Multiethnic Study of Atherosclerosis (MESA) have now extended their CV event follow up to 10 years. Given the younger age of the cohort and resultant lower event rates, enhancing the endpoint numbers will provide more stability and accuracy for the updated risk score model (ASTRO-CHARM version 2.0). <p></p> Specific Aim 2: To validate the ASTROCHARM tool using the Framingham Heart Study coronary artery calcium (CAC) cohort. The ASTRO-CHARM tool demonstrated robust measures of internal validity when assessed in the original combined cohort. These included accurate event rate calibration, as well as improvement in the c-statistic and clinical risk reclassification compared with traditional risk factors alone. However, external validation in another cohort is essential before broader implementation. The Framingham Heart Study (FHS) is the highly regarded original large U.S.-based population-based cohort, where CV risk scores originated. A cohort of the FHS underwent CAC scanning including 2740 subjects <65 years of age, with a mean 8 years of CV event follow up data, and is an ideal study in which to validate the ASTRO-CHARM model. <p></p> Specific Aim 3: To develop a mobile device application to facilitate broad implementation of the ASTRO-CHARM tool. The near universal availability of mobile technologies has enabled broader use of more sophisticated risk scores. Prior versions such as the Framingham Risk Score initially used tabular formats and adding of integer points, and were infrequently utilized in clinical practice. The Pooled Cohort Equation as part of the New 2013 ACC/AHA (American College of Cardiology/American Heart Association) Cholesterol Guidelines has witnessed brisk uptake of a more complex algorithm, partly due to a well-received mobile app that has witnessed more than 64,000 downloads in its first two months.Once validated, a similar tool developed for the ASTROCHARM will greatly enhance its clinical impact. <p></p> ASTROCHARM Version 2. The investigators have extended endpoint data to include another 145 events (304 total), with a median follow up of 10.9 years. They have used these expanded endpoints to refine the ASTRO-CHARM calculator and assessed measures of internal validity of the new calculator including discrimination and calibration which were all robust. They applied the ASTRO-CHARM model to the Framingham Heart Study CAC cohort (n=2057). The ASTRO-CHARM calculator showed good discrimination (c-statistic 0.79) and calibration (Goodness-of-Fit Chi-square: 13.2, p=0.16) in the Framingham study. The authors developed a prototype iPhone app for the ASTRO-CHARM and demonstrated this tool to NASA/NSBRI in late July of 2016. They are preparing the manuscript for scientific publication and the app for broad dissemination for NASA/NSBRI and terrestrial medicine applications. <p></p>
- API data.nasa.gov | Last Updated 2018-09-07T17:39:50.000Z
<p style="margin-left:0in; margin-right:0in">Busek proposes to develop a new form of passive electrospray thruster control which will enable extremely fast thruster operations and thereby unprecedented minimum impulse bits. Busek’s BET-300-P thruster is under active development as a precision reaction control system (RCS) which will provide orders of magnitude improvements over state-of-the-art alternative attitude control systems (ACS) for CubeSats and small spacecraft. The low inertia of CubeSats combined with vibrational disturbances and resolution limitations of state-of-the-art ACS presently limit precision body-pointing and position control. Busek’s electrospray thrusters aboard the ESA LISA Pathfinder (NASA ST-7) spacecraft, recently demonstrated control of a proof mass location to within ~2nm per root Hz over a wide band. The BET-300-P, enhanced by exploitation of its high-speed dynamic response in this program, seeks to extend that success to small spacecraft platforms.</p> <p style="margin-left:0in; margin-right:0in">Passively fed electrospray thrusters are highly compact, including fully integrated propellant supplies, and are capable of ~100nN thrust precision with 10’s of nN noise. Thrust can be accurately throttled over >30x, up to a scalable maximum of 10’s to 100’s of uN. While typically operated in largely continuous states they are unique in that emission can be electrically stopped/started at ms time scales. Thus, extremely low impulse bits may be achieved over very short durations, permitting throttling from <0.1uNs up to 100’s of uNs. Realization of this fundamental capability of the technology is presently limited by control circuitry. The proposed work seeks to study and overcome these limitations with a new control methodology.</p> <p>These traits, combined with >800s specific impulse, and thereby low propellant mass could enable these systems to replace traditional reaction wheel ACS and high-propellant mass cold gas systems; enabling milliarcsec control authority for CubeSats versus the present arcsec level SOA.</p>
- API data.nasa.gov | Last Updated 2018-09-05T23:06:53.000Z
The Europa Lander mission represents an enormous opportunity to capitalize on scientific discoveries at Europa by enhancing its planned exploration, toward a direct search for signs of life. The full understanding of Europa’s habitability will be established by the Europa Multiple Flyby Mission (EMFM). The EMFM payload, including highly capable imagers, spectrophotometers, mass spectrometers, and particle and wave sensors, will make critical observations of Europa’s subsurface ocean, its complex icy surface, and its surface-bounded exosphere to produce a clear picture of the extent and cycling of its water and chemical inventories. With this foundation, a follow-up lander will then be able to address hypotheses about key astrobiological markers in the icy surface. If deep plume activity is confirmed, the lander could potentially sample fresh, ocean-borne surface deposits for biosignature detection. With these ambitious objectives, relative to the timeframe for lander payload selection, it is absolutely imperative to focus attention on instrument technologies that both (1) address expected complex molecular detection and characterization requirements with exquisite sensitivity and specificity, and (2) are on a realistic technical path to compatibility with the extreme payload resource and environmental constraints of a Europa surface mission. We propose to mature a Europa-specific implementation of the Linear Ion Trap Mass Spectrometer (LITMS) investigation to meet these dual requirements in the search for signs of extant life. LITMS is a dual-ion source precision molecular analyzer derived from the substantial heritage of the Mars Organic Molecule Analyzer (MOMA) investigation under development in our lab for the ExoMars rover. LITMS brings the power of both gas chromatography mass spectrometry (GCMS) and laser desorption mass spectrometry (LDMS) of solid samples to fine spatial scales (sub-mm) with its precision analyses. As on Mars, detection of complex organics at fine scales offers significant advantages in examining features key to distinguishing biogenic and abiogenic molecules, compared to bulk analysis. LITMS further provides enhanced capabilities, compared to MOMA, including detection of both positive and negative ions, a wider range of molecular weights (to over 2 kDa), and direct evolved gas analysis – all of which substantially increase the sensitivity of LITMS to the widest possible range of molecular organic biosignatures within their geochemical context. LITMS has been developed for the past three years with support of the MatISSE program, and will achieve TRL 6 for Mars surface operations at the end of this year. To re-achieve TRL 6 for a Europa lander mission focused on extant life, we will focus our COLDTech effort in three critical areas: (1) Refinement and validation of the precision sampling GCMS + LDMS operational modes for characterization of trace complex molecular biosignatures in cryogenic Europan samples; (2) Analysis, testing, and optimization of the appropriate LITMS hardware and operational mitigation approaches for the intense penetrating radiation at Europa; and (3) Design and development of a flight-like LITMS brassboard for Europa that (3a) rigorously meets PDR-level TRL 6 criteria, and (3b) enables a flight design demonstrably compliant with the most stringent planetary protection and contamination control requirements of the mission. Lacking a requirement to redesign the core LITMS analyzer, which has already been developed at flight scale and meets extremely challenging measurement requirements for Mars missions, our proposed COLDTech development is able to devote significant and necessary attention to the Europa-specific features to minimize technical and cost risk of an eventual flight model. With COLDTech support we anticipate that LITMS could be among the few investigations that would be fully ready for the challenge of contributing to direct detection of life on Europa.
Precision Membrane Optical Shell (PMOS) Technology for RF/Microwave to Lightweight LIDAR Apertures, Phase IIdata.nasa.gov | Last Updated 2018-07-19T16:02:57.000Z
Membrane Optical Shell Technology (MOST) is an innovative combination of 1) very low areal density (40 to 200g/m2) optically smooth (<20 nm rms), metallic coated reflective membrane thin films, 2) advanced fabrication techniques that transform the films into self supporting shells through the introduction of permanent optically relevant double curvature, and 3) discrete active boundary control to enable rigid body alignment and maintainment of surface figure in face of environmental disturbances. Areal densities of better than 2 kg/m2 (including actuators) are projected. Current measured surface figure is ≈1 to 10 microns rms at up to the 15 cm size, and we are poised for further improvements. Demonstrated material and fabrication techniques are scaleable to at least the 2m+ diameter single surface apertures and larger apertures are possible through segmentation techniques. Proven stowage and deployment techniques enable space flight application. We propose advancing 1) the basic fabrication technology and 2) the TRL level of MOST apertures for ground and space based apertures. The key resulting innovation is implementation of low areal density, compact roll stowable approaches to realize low mass, low cost reflective apertures for RF/Microwave to LIDAR. Other NASA and DOD applications are expected as precision and aperture size increase.
- API data.nasa.gov | Last Updated 2018-07-19T09:15:42.000Z
Ridgetop developed an innovative, model-driven anomaly diagnostic and fault characterization system for electromechanical actuator (EMA) systems to mitigate catastrophic failures. Ridgetop developed a MIL-STD-1553 bus monitor and a MIL-STD-1553 bus controller that simulates the aircraft data bus, reads the environmental (i.e., altitude) and operational (i.e., response of system) data of a system and determines if a fault is manifesting; and if true determines the root cause and symptoms of the fault. Once an anomaly is detected, the Model-based Avionic Prognostic Reasoner (MAPR) solves a user-outlined state-space model, symbolically, using a Gauss-Newton optimization method and the information from the MIL-STD-1553 bus. This algorithm outputs a list of best fitting parameters to match the command to the actual performance. Rules are programmed in, based on results from principal component analysis . The rules determine both fault mode and the severity of that fault. The rules can distinguish between two failure modes: Mechanical jam and MOSFET failure, and healthy. The real-time processing will allow for critical evolutions in flight safety and provides a game-changing approach to condition-based maintenance. Once deployed, flight safety can be improved by allowing the on-board flight computers to read from the MAPR and update their control envelope based on its evaluations, reducing damage propagation and increasing operational safety. In Phase 2, we will develop a functioning ground-based prototype of the technology to show the efficacy of the method. A ground-based version of the tool is the best candidate for development to ease adoption by testing in a low-risk environment; this tool will be demonstrated at the end of Phase 2. The MAPR concept is also applicable to any system with a state-space representation but at this point it has been developed with EMAs in mind. The MAPR prototype is at TRL 5 and will reach a TRL 7 by the end of Phase 2.
- API data.nasa.gov | Last Updated 2018-07-19T07:49:57.000Z
Traditional SAR imaging at millimeter wave frequencies can provide excellent, high SNR, 3D images of features inside dielectric solids. However, imaging at these frequencies requires thousands of measurements; raster scanning for data collection is time consuming; and data analysis and image rendering requires additional time. These limitations make millimeter wave SAR imaging for nondestructive evaluation prohibitive outside the lab. We propose to show feasibility of overcoming these restrictions by designing a real-time, high-resolution, portable and 3D imaging system for terrestrial and in-space inspection applications. We will demonstrate ability to produce high-fidelity 3D images from substantially reduced data with minimal image quality degradation. We will also investigate further enhancements via spectral estimation or compressive sensing techniques. In Phase I we will design an adaptive, custom sampled, SAR-based millimeter wave imaging system for nondestructive inspection of complex composites and structures. The design of this imaging system will be based on novel and substantial innovations to a well establish knowledge base. The innovations involve overcoming hardware and software limitations that currently make 3D imaging at millimeter wave frequencies slow, cumbersome and impractical for widespread use. Our goal is to design a system with: center frequency in the millimeter wave range; significant bandwidth; high-spatial and range resolutions; rapid image data collection; real-time image rendering; ability to image multi-layer structures made of different materials; high system dynamic range (high detection sensitivity); electrical and mechanical design allowing adaptation to use in-space; modular and frequency-scalablity to accommodate large structures; user friendly design to allow operation by people of various skill sets. The Phase I effort will include simulations and small-scale testing.
- API data.nasa.gov | Last Updated 2018-07-19T17:54:04.000Z
Anomaly detection has recently become an important problem in many industrial and financial applications. In several instances, the data to be analyzed for possible anomalies is located at multiple sites and cannot be merged due to practical constraints such as bandwidth limitations and proprietary concerns. At the same time, the size of data sets affects prediction quality in almost all data mining applications. In such circumstances, distributed data mining algorithms may be used to extract information from multiple data sites in order to make better predictions. In the absence of theoretical guarantees, however, the degree to which data decentralization affects the performance of these algorithms is not known, which reduces the data providing participants' incentive to cooperate.This creates a metaphorical 'prisoners' dilemma' in the context of data mining. In this work, we propose a novel general framework for distributed anomaly detection with theoretical performance guarantees. Our algorithmic approach combines existing anomaly detection procedures with a novel method for computing global statistics using local sufficient statistics. We show that the performance of such a distributed approach is indistinguishable from that of a centralized instantiation of the same anomaly detection algorithm, a condition that we call zero information loss. We further report experimental results on synthetic as well as real-world data to demonstrate the viability of our approach. The remaining content of this presentation is presented in Fig. 1.
- API data.nasa.gov | Last Updated 2018-07-19T08:28:51.000Z
<p>The Global Aerosol Measurement System (GAMS) project is developing a new, low cost satellite capability for measuring the properties and distributions of particles in the upper troposphere and lower stratosphere (collectively, the UTLS). This altitude region is important because there have been observed increases in the amount of particles in the UTLS. These particles typically reflect sunlight back into space and cool the Earth. GAMS will measure the altitudes and amounts of these particles by looking to the side of the spacecraft, through the thickness of Earth’s atmosphere, and provide detailed information about how particles are changing in the UTLS.</p><p>The goal of the Global Aerosol Measurement System (GAMS) project is to develop needed technologies and observation strategies to optimally measure the distributions and properties of particles in the upper troposphere and lower stratosphere (UTLS). The GAMS concept is based on the limb-scattering measurement techniques used on past sensors, most directly from the heritage of the Ozone Mapping and Profiling Suite (OMPS) Limb Profiler (LP) currently flying on board the Suomi National Polar-orbiting Partnership (NPP) spacecraft. OMPS-LP was launched on Suomi NPP in 2011, with the next planned launch of this instrument in 2022 on the next generation Joint Polar Satellite System-2 (JPSS-2). Because of the length of time between the NPP and JPSS-2 launches there is the potential for a significant data gap for these important measurements. The GAMS concept is intended to be a simple and low cost measurement system that could be ready to fill such a gap.</p><p> </p><p>The current OMPS-LP system measures light reflected by particles in the UTLS by looking behind the Suomi NPP path, looking through the thickness of Earth’s atmosphere (i.e., the limb). Although OMPS-LP has proven capable of detecting the presence of background particles in the UTLS, as well as particles from volcanic eruptions and meteorites entering Earth’s atmosphere from space, it has very limited spatial coverage and suffers from sensitivity issues since it preferentially sees particles in one direct with respect to the sun. GAMS seeks to overcome both limitations by making measurements of reflected light In two or more directions relative to the spacecraft flight. Because GAMS focuses only on the limb profiling capabilities (versus the more comprehensive but more complicated OMPS system) it can be contained in a relatively smaller spacecraft, which will reduce deployment costs. Additional increased spatial coverage can be realized by flying multiple copies of the GAMS instrument in different orbits.</p><p> </p><p>In this stage of the GAMS project we are working to develop capabilities for adding additional spectral channels to our detector system. We initially targeting 350 nm for altitude registration and 675 nm for aerosol detection. We are now developing an extension to include an additional channel at 1020 nm for aerosol detection. This channel will provide additional sensitivity to aerosol in the lower stratosphere, provides heritage overlap with other sensors (e.g., SAGE), and paired with the 675 nm channel provides additional information to recover other aspects of the aerosol distribution (e.g., particle size). We are additionally developing an observation simulator based on model output from the NASA Goddard Earth Observing System (GEOS-5) atmospheric model. This will allow us to prototype assimilation methodologies to ingest the eventual GAMS observations into aerosol prediction models.</p>