- 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.
- API data.nasa.gov | Last Updated 2019-06-03T15:17:07.000Z
This data set provides a time series of global peatland carbon balance and carbon dioxide emissions from land use change throughout the Holocene (the past 11,000 yrs). Global peatland carbon balance was quantified using a) a continuous net carbon balance history throughout the Holocene derived from a data set of 64 dated peat cores, and b) global model simulations with the LPX-Bern model hindcasting the dynamics of past peatland distribution and carbon balance. CO2 emissions from land-use change are based on published scenarios for anthropogenic land use change (HYDE 3.1, HYDE 3.2, KK10) covering the last 10,000 years. This combination of model estimates with CO2 budget constraints narrows the range of past anthropogenic land use change emissions and their contribution to past carbon cycle changes.
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 2019-04-22T02:52:42.000Z
These data are the Goddard Satellite-based Surface Turbulent Fluxes Version-2c (GSSTF2c) Dataset recently produced through a MEaSUREs funded project led by Dr. Chung-Lin Shie (UMBC/GEST, NASA/GSFC), converted to HDF-EOS5 format. The stewardship of this HDF-EOS5 dataset is part of the MEaSUREs project. GSSTF version 2b (Shie et al. 2010, Shie et al. 2009) generally agreed better with available ship measurements obtained from several field experiments in 1999 than GSSTF2 (Chou et al. 2003) did in all three flux components, i.e., latent heat flux [LHF], sensible heat flux [SHF], and wind stress [WST] (Shie 2010a,b). GSSTF2b was also found favorable, particularly for LHF and SHF, in an intercomparison study that accessed eleven products of ocean surface turbulent fluxes, in which GSSTF2 and GSSTF2b were also included (Brunke et al. 2011). However, a temporal trend appeared in the globally averaged LHF of GSSTF2b, particularly post year 2000. Shie (2010a,b) attributed the LHF trend to the trends originally found in the globally averaged SSM/I Tb's, i.e., Tb(19v), Tb(19h), Tb(22v) and Tb(37v), which were used to retrieve the GSSTF2b bottom-layer (the lowest atmospheric 500 meter layer) precipitable water [WB], then the surface specific humidity [Qa], and subsequently LHF. The SSM/I Tb's trends were recently found mainly due to the variations/trends of Earth incidence angle (EIA) in the SSM/I satellites (Hilburn and Shie 2011a,b). They have further developed an algorithm properly resolving the EIA problem and successfully reproducing the corrected Tb's by genuinely removing the "artifactitious" trends. An upgraded production of GSSTF2c (Shie et al. 2011) using the corrected Tb's has been completed very recently. GSSTF2c shows a significant improvement in the resultant WB, and subsequently the retrieved LHF - the temporal trends of WB and LHF are greatly reduced after the proper adjustments/treatments in the SSM/I Tb's (Shie and Hilburn 2011). In closing, we believe that the insightful "Rice Cooker Theory" by Shie (2010a,b), i.e., "To produce a good and trustworthy 'output product' (delicious 'cooked rice') depends not only on a well-functioned 'model/algorithm' ('rice cooker'), but also on a genuine and reliable 'input data' ('raw rice') with good quality" should help us better comprehend the impact of the improved Tb on the subsequently retrieved LHF of GSSTF2c. This is the Daily (24-hour) product; data are projected to equidistant Grid that covers the globe at 1x1 degree cell size, resulting in data arrays of 360x180 size. A finer resolution, 0.25 deg, of this product has been released as Version 3. The GSSTF, Version 2c, daily fluxes have first been produced for each individual available SSM/I satellite tapes (e.g., F08, F10, F11, F13, F14 and F15). Then, the Combined daily fluxes are produced by averaging (equally weighted) over available flux data/files from various satellites. These Combined daily flux data are considered as the "final" GSSTF, Version 2c, and are stored in this HDF-EOS5 collection. There are only one set of GSSTF, Version 2c, Combined data, "Set1" The "individual" daily flux data files, produced for each individual satellite, are also available in HDF-EOS5, although from different collections: GSSTF_Fxx_2c, where Fxx are the individual satellites (F08, F10, etc..) The input data sets used for this recent GSSTF production include the upgraded and improved datasets such as the Special Sensor Microwave Imager (SSM/I) Version-6 (V6) product of brightness temperature [Tb], total precipitable water [W], and wind speed [U] produced by the Wentz of Remote Sensing Systems (RSS), as well as the NCEP/DOE Reanalysis-2 (R2) product of sea skin temperature [SKT], 2-meter air temperature [Tair], and sea level pressure [SLP]. Relevant to this MEaSUREs project, these are converted to HDF-EOS5, and are stored in the GSSTF_NCEP_2c collection. Please use these
- 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 2018-07-19T05:28:43.000Z
This dataset contains RAW DATA of the STEINS flyby Phase from 4 August 2008 until 5 September 2008. The closest approach (CA) took place on 5 September 2008
- 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.