- API data.nasa.gov | Last Updated 2018-07-19T07:45:39.000Z
CoolCAD Electronics has developed a patent-pending technology to design and fabricate Silicon Carbide (SiC) MOSFET opto-electronic integrated circuits (ICs). We both fully design and fabricate these SiC Opto-Electronic ICs in the U.S. using our own design methodologies, SiC process recipes and in-house fabrication facility. We will design, fabricate and test SiC Extreme, Vacuum and Deep Ultraviolet photodetectors. We will prototype PN Junction and Schottky barrier linear photodiodes, as well as low dark count avalanche photodiodes. We will design and fabricate a two-dimensional 256 by 256 passive UV SiC focal plane array. Array elements will be fabricated in-house, out of both PN junction and Schottky barrier detectors, using CoolCAD's process and facilities. We will design and fabricate opto-electronic integrated circuits, where we will integrate various types of detectors with a MOS operational amplifier into a single IC to actively convert the photo current to usable voltage levels. We will also design and fabricate an integrated photodetector and 3-Transistor pixel for active readout. Multiple active pixel readout 3-T circuits will be an array to form a SiC active pixel MOS Deep UV imager. Our in-house fabrication process will also be upgraded. We will automate optical alignment to improve our microfabrication resolution and reduce minimum feature size. We will perform gate oxide anneals to improve carrier mobility. Improving mobility and reducing the minimum feature size will increase MOSFET performance and increase speed of opto-integrated circuits. Furthermore, SiC allows for optoelectronic operation at high temperatures. We will test our circuits up to 500C and utilize special metal contact stacks to enhance high temperature reliability. Finally, we will make our in-house process available to NASA and provide a process development kit for use of our fabrication facility to prototype new application specific SiC integrated circuits.
NCA-LDAS Noah-3.3 Land Surface Model L4 Daily 0.125 x 0.125 degree V2.0 (NCALDAS_NOAH0125_D) at GES DISCdata.nasa.gov | Last Updated 2019-07-01T15:17:21.000Z
The National Climate Assessment - Land Data Assimilation System, or NCA-LDAS, is an integrated terrestrial water analysis system created for sustained assessment, analyses, and dissemination of hydrologic indicators in support of the United States Global Change Research Program's NCA activities. NCA-LDAS features high resolution, gridded, daily time series data products of terrestrial water and energy balance stores, states, and fluxes over the continental U.S., derived from land surface hydrologic modeling with multivariate assimilation of satellite Environmental Data Records (EDRs). The overall goal is to improve scientific understanding, adaptation, and management of hydrologic and related energy resources during a changing climate. This NCA-LDAS version 2.0 data product was simulated for the continental United States for the satellite era from January 1979 to December 2016. The core of NCA-LDAS is the multivariate assimilation of past and current satellite based data records within the Noah Version 3.3 land-surface model (LSM) at 1/8th degree resolution using NASA's Land Information System (LIS; Kumar et al. 2006) software framework during the Earth observing satellite era. The temporal resolution is daily. The file format is NetCDF. Jasinski et al. (2019) provide an overview of NCA-LDAS and also an analysis and evaluation of mean annual hydrologic trends over the conterminous U.S. Details on the data assimilation used in NCA-LDAS are described in Kumar et al. (2018). NCA-LDAS includes 42 variables including land-surface fluxes (e.g. precipitation, radiation and latent and sensible heat, etc.), stores (e.g. soil moisture and snow), states (e.g., surface temperature), and routing variables (e.g., runoff, streamflow, flooded area, etc.), driven by the atmospheric forcing data from North American Land Data Assimilation System Phase 2 (NLDAS-2; Xia et al., 2012). NCA-LDAS builds upon NLDAS through the addition of multivariate assimilation of earth observations such as soil moisture (Kumar et al, 2014), snow (Liu et al, 2015; Kumar et al, 2015a) and irrigation (Ozdagon et al, 2010; Kumar et al, 2015b). The EDRs that have been assimilated into the NCA-LDAS include soil moisture and snow depth from principally microwave sensors such as SMMR, SSM/I, AMSR-E, ASCAT, AMSR-2, SMOS, and SMAP, irrigation intensity estimates from MODIS, and snow covered area from MODIS and from the multisensor IMS snow product.
- API data.nasa.gov | Last Updated 2018-07-19T08:50:38.000Z
<p>Superconducting transition-edge sensors (TESs) are the state-of-the art technology for microcalorimeter and bolometer applications across the electromagnetic spectrum. We propose to design, fabricate, and test what we call a magnetically-tuned TES (or MTES). The leading theoretical TES physics understanding predicts our MTES concept will take the current state of the art TES and (1) Increase the signal, (2) Decrease the pulse recovery time, (3) Reduce the noise, and (4) Increase the energy resolving power.<br /> </p> <p>The magnetically-tuned TES (or MTES) takes characteristics that we have only recently come to understand are present and important in all state-of-the-art TES sensors and uses them in an interesting new combination. Magnetic tuning simply changes the resistive transition of the TES sensor.</p><p>Our research program will answer the following questions in turn. Does an MTES reduce the relative sensitivity of the resistive transition in current? Does a MTES reduce the relative sensitivity of the resistive transition in current while maintaining a large relative sensitivity of the resistive transition in temperature? Does the MTES resistive transition depart from the weak-link theoretical model and if so in what ways?</p>
- API data.nasa.gov | Last Updated 2018-09-07T17:42:54.000Z
We propose to develop a passive and active source neutron and gamma-ray spectrometer to characterize the abundance of near-surface hydrogen and rock-forming elements on a variety of spacecraft missions to planetary bodies (Moon, Mars, NEOs, comets). The instrument (initially at TRL-2) will use a new type of scintillator, Cs2YLiCl6:Ce (CLYC). CLYC is self-annealing at room temperature and provides both high efficiency detection of neutrons and excellent energy resolution for gamma-rays. The proposed work will investigate the use of a CLYC scintillator with a cosmic-ray background source as well as with an active pulsed neutron generator (PNG) source of neutrons for geochemical analysis. Our goal is to progress the overall instrument package (detector and PNG) to TRL-4. The ability of CLYC to detect both neutrons and gamma-rays (with a photomultiplier tube) has been demonstrated via a previously awarded NASA SBIR to RMD, thus we assert CLYC at TRL-3. The use of CLYC with a PNG is at TRL-2, and our proposal will develop timing-based electronics for the coupled system and perform testing in a laboratory environment, resulting in an overall instrument at TRL-4. Description of Methodology to be used: Task 1: Monte-Carlo modeling to determine optimal detector size based on minimum planetary radius and mission parameters as well as a science trade study of D-D vs. D-T pulsed neutron source with variable pulse rates and length. Task 2: Development of methods for maintaining high-performance characteristics of a CLYC detector in the space environment. Task 3: Development of integrated detector and electronics modules capable of operating in both passive and active source modes. Task 4: Testing of the integrated detector and electronics system with an isotopic and pulsed neutron source. Description of Relevance to PICASSO: This work supports the goals of PICASSO as it increases the TRL of a platform-independent (orbital or surface) instrument that is well suited for several medium-class planetary missions in NASA's Decadal Survey. For example, several science mission objectives specifically referred to by NASA are geochemical characterization during a comet sample return mission, a Trojan Tour and Rendezvous mission, and a rover-based Lunar South Pole-Aitken Basin sample return mission. The geochemical data provided by this instrument would directly address NASA's goals and objectives to 'characterize the chemical composition of comets', and to 'determine water resources in lunar polar regions and near-Earth asteroids'.
- 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 low-cost, lightweight Hall Effect Thruster (HET) Power Processing Unit (PPU) at targeted 1kW/kg power density with more than 97% efficiency. The proposed PPU solution adopts advanced GaN power MOSFETs and PCB based planar magnetics technology to enable high switching frequency operation. Reduced headcount of magnetics, semiconductors and associated driver integrated circuits will allow for significant size reduction of all passive components to support ultra-high power density designs. This innovation will further miniaturize HET PPUs from today’s state-of-art by an anticipated 30% in volume and mass, with cost reductions exceeding 50% versus SOA solutions.</p> <p style="margin-left:0in; margin-right:0in">The unique advantages of the proposed system can be summarized in three parts. First, the system utilizes a novel single-core multi-port circuit topology which integrates all the PPU subsystems through a single stage power conversion using a single multi-winding transformer. This significantly reduces system volume, weight, and cost. Second, the power flow control for each subsystem is fully independent regardless of power stage sharing. Each subsystem has its own phase shift control to regulate the desired output voltage and current. Third, the proposed PPU circuit topology is essentially a soft-switching DC-DC converter which can ensure zero-voltage-switching operation for all the switching devices. The proposal adopts the advanced GaN power MOSFETs and PCB based planar magnetics technology to enable high switching frequency operation, which supports a 30% size reduction of magnetics and other passive components in the high-efficiency and high-power density design.</p> <p style="margin-left:0in; margin-right:0in">In Phase II Busek will characterize the breadboard PPU with sub-kilowatt Hall thrusters and develop a proto-flight brass-board level unit using GaN devices. At the conclusion of Phase II, Busek will deliver a PPU to NASA for additional characterization testing.</p>
- API data.nasa.gov | Last Updated 2018-07-19T08:03:09.000Z
We propose an innovative, low coherence probe for rapid measurement of free-form optical surfaces based on a novel method of spectrally controlled interferometry. The key innovations are the use of a new interferometric modality and a novel non-contact optical probe that together measure high surface slope acceptance angles to nanometer sensitivity. When the probe is integrated with a precision motion, x, y, & z metrology frame (Phase II) (see Figure-1), it will meet NASA's need to measure free-form optical surfaces from 0.5 cm to 6 cm diameter ranging from F/2 to F/20, including slopes up to 20 degrees (with potential for 60 degrees), with an uncertainty targeted at 2 nm RMS. The probe operation does not require tilting to measure slopes. This results in this simplified cartesian metrology frame, also critical to achieve 2 nanometer measurement uncertainty. These features: nanometer resolution and 20 degree slope acceptance angle, have up to this time not been found in a single probe or sensor, non-contact or contact. This proposal integrates the spectrally controlled source and breadboard probe developed under a previous SBIR to develop a practical detection method reading the technology for a successful SBIR Phase II project.
- API data.nasa.gov | Last Updated 2018-07-19T13:08:36.000Z
Current and future programs of near-Earth and deep space exploration performed by NASA and Department of Defense require the development of reconfigurable, high-speed intra-satellite interconnect systems based on switching fabric active backplane architecture with high-speed serial interfaces. Electrical and/or optical transponders operating with Space Wire, Fire Wire, or Gigabit Ethernet protocols are required to support the associated data interconnects. The systems must be easily upgradeable, power-efficient, fault-tolerant, EMI-protected, and capable to operate effectively for long periods of time in harsh environmental conditions including radiation effects. To address the described needs, Advanced Science and Novel Technology Company proposes to develop a basic concept of the novel, optical, radiation-tolerant transponder, which will be implemented as a hermetically-sealed pigtailed multi-chip module with an FPGA-friendly parallel interface and will feature an improved radiation tolerance, high data rate, low power consumption, and advanced functionality. The transponder will utilize the company's patent-pending current-mode logic library of radiation-hardened-by-architecture cells. 8B10B encoding will be used to achieve data disparity equal to 0 and perform a reliable clock recovery. The encoder and decoder will utilize the company's patented half-rate architecture that improves radiation tolerance. The proposed characteristics will be achieved by utilization of an advanced SiGe BiCMOS technology.
- API data.nasa.gov | Last Updated 2018-07-19T09:59:24.000Z
<p>Over the past year, the X-Band Atmospheric Doppler Ground-based Radar (X-BADGER) transmitter has undergone a major upgrade from a high voltage traveling-wave tube to a solid-state power amplifier (SSPA). For X-BADGER to reach its highest potential, the addition of a digital receiver is necessary to utilize the recent hardware upgrade. The small size and mobility of X-BADGER makes it attractive for field deployment for ground validation (GV) of spaceborne missions involving precipitation and the hydrological cycle, such as the Global Precipitation Measurement (GPM) mission, Surface Water and Ocean Topography (SWOT), and the Soil Moisture Active Passive (SMAP) mission.</p> <p>The X-BADGER system is based on the ER-2 Doppler (EDOP) radar, which was built in 1994, flown in multiple field campaigns, and worked consistently as a ground-based vertically pointing radar with an antenna on the rooftop of Building 33 from 2007 until 2011. The objective of this year’s IRAD project is to complete the creation of a new solid-state radar with two digital receivers. One digital receiver will be dedicated for the zenith beam and the other will be dedicated for the horizontal and vertical channels for the dual polarimetric forward pointing beam. In the previous EDOP system, the data required post-processing after the transmitter stopped. The addition of digital receivers will allow for real-time processing of data and creation of Quicklooks in near real-time, which is crucial for field campaign performance. An additional benefit of upgrading to a digital receiver is that all of the radars in the Microwave Sensors Lab use the same type of digital receiver.</p><p>As soon as the installation of the two digital receivers to X-BADGER is complete, the radar will move to Wallops for long-term deployment as part of the GPM Wallops Precipitation Research Facility (PRF) for Error Characterization led by Dr. Walt Petersen (GPM Ground Validation Science Manager). The radar will be used for studies involving precipitation error characterization, variability in satellite field of view (FOV), and precipitation vertical profile physics. In the future, it is envisioned that X-BADGER could be deployed as part of the existing GSFC/WFF PRF multi-frequency radar infrastructure for support of additional future mission field campaign studies. We are poised to obtain funding for the GPM OLYMPEX field campaign in FY16 if X-BADGER is completed and initial testing of the radar in an operational setting is completed during FY15.</p><p> </p>
- API data.nasa.gov | Last Updated 2018-07-19T07:36:15.000Z
Space-borne radar platforms are becoming increasingly prevalent in current and planned missions by NASA and partner organizations (e.g. the European Space Agency [ESA]) for a number of microwave remote sensing applications in the terrestrial and space domains. Examples of such missions include the Mars Express, Mars Reconnaissance Orbiter (MRO), BIOMASS, JUICE, Global Precipitation Measurement system, CloudSat, and Cassini. Depending upon the specific application, certain frequency ranges are typically deemed more optimal than others. In applications wherein the radar signal must achieve deep penetration through layers such as ice, vegetation, and top-soil, low-frequency radar systems (typically sub-500MHz) such as those of the MRO, Mars Express, JUICE, and BIOMASS are typically favored over higher-frequency alternatives like those used in CloudSat and Cassini due to lower signal loss associated with conductive ground layers. Despite this advantage of low-frequency signals, when using such signals to perform terrestrial and Martian remote sensing operations from space, the ionosphere will distort propagating electromagnetic (EM) fields, with these distortive effects exacerbating as the frequency reduces. Without adaptive, robust distortion prediction and mitigation techniques, the ionosphere will continue posing a barrier to current and future NASA/ESA remote sensing missions seeking to probe deep into ice, vegetation, and ground layers. Furthermore, despite the presence of external data sources such as the Global Positioning System to perform ionospheric mapping, it may be desired to map the ionosphere in real-time using the same low-frequency radar to capture instantaneous snapshots of the ionosphere’s properties during the radar’s flight path to provide more accurate information to bias mitigation algorithms. Therefore, the development of robust, low-frequency ionospheric mapping techniques represents an equally important and complementary pursuit to developing bias correction techniques. Similar issues will assume relevance when sounding extraterrestrial sub-surface environments containing media exhibiting exotic EM properties, potentially hindering the success of underground water and hydrocarbon detection without proper mitigation measures. However, these efforts all hinge upon accurate modeling of the environments EM characteristics to better understand the signal-environment interaction and its dependence upon the specific radar system used, which is the central theme of my proposed research. I will first extend and unify a number of isolated models concerning EM wave propagation in complex media into a comprehensive model that more accurately predicts the received EM fields at the radar platform. I will then implement this model in numerical EM codes to study how the ionosphere and complex sub-surface topologies can be expected to distort low-frequency EM waves propagating through these environments. Numerical results and conclusions on signal distortions incurred, as well as on the performance limits of current ionospheric mapping and sub-surface sounding techniques, as a function of center operating frequency, signal bandwidth, antenna geometry, and environmental topology, are expected to be the final outcomes of this research, which are expected to markedly aid NASA/ESA mission-related trade and performance studies while stimulating development of comprehensive, robust low-frequency ionospheric mapping and environmental distortion mitigation techniques.
- API data.nasa.gov | Last Updated 2018-07-19T11:12:30.000Z
NASA's strategic goals call for innovation in space technology for our nation's explorative future. Early phase paraffin fuel technology could enable practical hybrid motor use by producing high regression rates. Further, the creation of a robust and novel fuel, that overcomes paraffin mechanical property drawbacks, would produce high payoffs. The proposed research specifically will investigate polymer addition to paraffin grains, study the particle entrainment theory, evaluate hydride and metal additives, and demonstrate hypergolic ignition. We hope to find that polymers strengthen the low mechanical properties of paraffin. We will design, build, and demonstrate an experiment in which particle entrainment can be seen and understood. We will evaluate additives to increase performance and facilitate reliable and hypergolic ignition. Outreach to student run clubs and undergraduate engineers will also play an integral role demonstrating the promise of paraffin propellants through sounding rockets. A high performance paraffin based grain is a game-changing technology that could lead to the economical use of hybrid rockets.