2008 ACT Projects Awarded
NASA’s Science Mission Directorate Awards Funding for 16 Projects Under
the Advanced Component Technologies (ACT) program of the Earth Science Technology Office
(ROSES 2008 Solicitation NNH08ZDA001N-ACT)
11/12/2008 – NASA’s Science Mission Directorate, NASA Headquarters, Washington, DC, has selected proposals for the 2008 Advanced Component Technologies program solicitation (ACT-08) in support of the Earth Science Division (ESD). The ACT-08 will support the development of instrument components and subsystems technologies for Earth Science missions/measurements recommended by National Research Council (NRC) Decadal Survey.
The ESD is awarding 16 proposals, for a total dollar value over a three-year period of approximately $16 million, through the Earth Science Technology Office located at Goddard Space Flight Center, Greenbelt, Md.
The Advanced Component Technologies (ACT) program seeks proposals for technology development activities leading to new component- and subsystem-level airborne and space-based measurement techniques to be developed in support of the Science Mission Directorate’s Earth Science Division. The objectives of the ACT program are to research, develop, and demonstrate component- and subsystem-level technology development that:
- Reduce the risk, cost, size, volume, mass, and development time of Earth observing instruments and platforms, and
- Enable new Earth observation measurements.
The ACT program brings instrument components to a maturity level that allows their integration into other NASA technology programs such as the Instrument Incubator Program. Some of these components are directly infused into mission designs by NASA flight projects and others “graduate” to other technology development programs for further development.
|Michael Dobbs, ITT Industries Space Systems LLC
A Low Cost, Ultra-Lightweight, Optically Fast f/1.2, Corrugated Mirror Telescope Array for Lidar and Passive Earth Science Missions
|Houfei Fang, Jet Propulsion Laboratory
A Large High-Precision Deployable Reflector for Ka- and W-band Earth Remote Sensing
|James Hoffman, Jet Propulsion Laboratory
Advanced Thermal Packaging Technologies for RF Hybrids
|Rainer Illing, Ball Aerospace & Technologies Corporation
PolZero: Time-Domain Polarization Scrambler for Wavelength-Diverse Sensors
|Scott Janz, NASA Goddard Space Flight Center
Hybridized Visible-NIR Blind (Al, In)GaN Focal Plane Arrays
|Michael Krainak, NASA Goddard Space Flight Center
Ultra-Sensitive Near-Infrared Optical Receiver Using Avalanche Photodiodes
|Cathy Marx, NASA Goddard Space Flight Center
Hybrid Doppler Wind Lidar Transceiver
|Matthew McGill, NASA Goddard Space Flight Center
Detector Technology Development for Cloud-Aerosol Transport Lidar
|TK Meehan, Jet Propulsion Laboratory
A GNSS RF ASIC For Digital Beamforming Applications
|Martin Mlynczak, NASA Langley Research Center
Far-Infrared Extended Blocked Impurity Band (FIREBIB) Detectors Optimized for Earth Radiance Measurements
|Mark Phillips, Lockheed Martin Coherent Technologies
CLASS Instrument Technology Maturation for ASCENDS
|Steven Reising, Colorado State University
Advanced Component Development to Enable Low-Mass, Low-Power High-Frequency Radiometers for Coastal Wet-Tropospheric Correction on SWOT
|David Rider, Jet Propulsion Laboratory
In-Pixel Digitization Read Out Integrated Circuit for the Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission
|Paul Siqueira, University of Massachusetts
A Low Power, High Bandwidth Receiver for Ka-band Interferometry
|Robert Taylor, Composite Technology Development
Large Aperture, Solid Surface Deployable Reflector
|Mark Thomson, Jet Propulsion Laboratory
Large Deployable Ka-Band Reflect Array for the SWOT Mission
|Title||A Low Cost, Ultra-Lightweight, Optically Fast f/1.2, Corrugated Mirror Telescope Array for Lidar and Passive Earth Science Missions|
|Full Name||Michael Dobbs|
|Institution Name||ITT Industies Space Systems LLC|
|This “cross cutting” advanced technology component ‘corrugated mirror’ will result in a significantly less expensive and much quicker method to operationalize an optically fast (f/1.2), ultra-lightweight (~7kg/m2), large area (>1m2) telescope which can be applied to several of NASA’s Earth Science (Decadal) and Exploration missions.
A significant number of the Earth Science missions utilize active remote sensing, which requires considerable power-aperture product to meet the science objectives. These include: ICESatII, DENDynI, ASCENDS, ACE, LIST, 3D Winds, and GACM. This provides the mission engineer with a new capability to trade large apertures, which are currently unaffordable, against large, expensive laser power. Mission design studies have demonstrated that upwards of 3 meters of aperture can be accommodated in a mid-class launch vehicle, whereas past efforts have been limited to 1 meter. This technology also enables new configurations of multiple telescopes as an alternative to large scanning telescopes, and their attendant challenges to the spacecraft. In addition, there are passive missions which require large apertures, for which deployable telescopes have been considered, but which are expensive.
ITT has developed and demonstrated the cost, time and mass advantages of the ‘corrugated mirror’ technology using internal funds. ITT has also partnered with NASA under the IPP to test a corrugated mirror under cryogenic conditions. However, these systems are optically slow (f/4) and do not enable the widest range of missions and benefits to NASA that are possible. This effort will demonstrate that the significant cost, schedule and mass advantages of the corrugated technology can be maintained when manufacturing optical fast (f/1.2) systems, which are required to enable the most compact packaging, and thus the largest area for the smallest launch vehicle. This effort will produce an f/1.2 – 0.5 meter diameter mirror and corresponding compact telescope design, suitable for ASCENDS and similar active missions.
|Title||A Large High-Precision Deployable Reflector for Ka- and W-band Earth Remote Sensing|
|Full Name||Houfei Fang|
|Institution Name||Jet Propulsion Laboratory|
|The objectives and benefits of this project are to develop a new generation of large, high RF frequency and high gain in-space deployable reflector technology to enhance the Aerosol/Cloud/Ecosystem (ACE) and enable NEXRAD In Space (NIS) missions. The functionality of a reflector is determined by aperture diameter (D) and surface RMS error (RMS). Larger diameter implies better science performance and smaller RMS indicates higher RF frequency. The best deployable reflector that has been demonstrated thus far is in the vicinity of D/RMS=20,000 to 30,000 [Im, Thomson and et al., 2007] with RF frequency much lower than 10 GHz. This proposed New Generation Reflector Technology (NGRT) will significantly increase the D/RMS ratio and RF frequency to enhance ACE (D/RMS=65,000, 35/94 GHz) and enable NIS (D/RMS=170,000, 35 GHz).
This NGRT will be implemented by leveraging and integrating several recently developed material technologies. These newly developed material technologies include Shape Memory Polymer (SMP) material, high-precision Membrane Shell Reflector Segment (MSRS) casting process, near zero CTE membrane material Novastrat [Poe, 2006], and PVDF electro-active membrane [Fang et al., 2007]. The architecture of this NGRT has a number of high precision MSRSs supported by a SMP tetrahedral truss to form a reflector. A tetrahedral truss offers almost one order of magnitude higher precision than any currently used tensioning cable truss [Hedgepeth, 1982] and can provide a very irregular surface contour (e.g. dual-frequency surface for ACE) that is extremely difficult, if not impossible, for a tensioning cable truss. Compared to the big loss and scattering of the high-frequency RF signal caused by currently used mesh reflective surface, MSRSs form a high definition, smooth and continuous surface to assure very high gain for high RF frequencies.
This project will last for three years and increase the TRL from 2 at entry to 4 at exit.
|Title||Advanced Thermal Packaging Technologies for RF Hybrids|
|Full Name||James Hoffman|
|Institution Name||Jet Propulsion Laboratory|
|RF-hybrid technologies enable smaller packaging and mass reduction in radar instruments, especially for subsystems with dense electronics, such as electronically steered arrays (ESA). Despite benefits from RF-hybrids in spaceborne radars, necessary increases in the power density of these electronics requires improved thermal management and reliability. We will combine our experience developing lower-frequency RF-hybrid T/R modules, with new materials for improved thermal performance of electronics, and a recently completed, SBIR-funded, MMIC L-band T/R module. We will combine advanced substrate and housing materials with a thermal reservoir, and develop new packaging techniques to significantly improve thermal-cycling properties.
The benefits of this work are reduced size and mass, and increased allowable power density of ESAs that use RF-hybrids, with improved reliability for all thermally-cycled RF-hybrids. Successful flight integration of any of these materials is an evolutionary advance in hybrid technology. The synergistic benefits of successfully combining all proposed technologies is a revolutionary advance, and an enabling step for less expensive, more compact, but robust, high power-density ESAs. One such ESA feed is being studied for DESDynI’s (Deformation, Ecosystem Structure, and Dynamics of Ice) radar. These thermally robust and stable RF-hybrids will also greatly benefit development of extremely accurate phase-tracking receivers, such as that proposed for SWOT (Surface Water Ocean Topography).We will design and test a representative phased array tile, using these advanced materials for RF-hybrid fabrication to increase the heat transfer of the electronics to a local thermal reservoir. This will decrease local heating, thermal gradients and thermal variability within the RF-hybrid modules, considerably increasing reliability and/or increasing the tolerance for higher power.
With an entry TRL of 3 and a planned exit of 5 over a three year period of performance, we will model, design, fabricate, and test the phased array tile.
|Title||PolZero: Time-domain polarization scrambler for wavelength-diverse sensors|
|Full Name||Rainer Illing|
|Institution Name||Ball Aerospace & Technologies Corporation|
|Spectroscopic sensors for Earth observation must always deal with the polarization of the incoming light. Failure to account for or eliminate the radiometric effects of instrument polarization sensitivity leads to degraded performance and ambiguous results. The most efficient method for attaining maximum performance is to depolarize the incoming beam near the entrance aperture. A variety of methods have been employed, with varying degrees of success; all rely on scrambling the polarization, either in the spectral (Lyot depolarizer) , spatial (crystal depolarizer), or temporal domain. All have some drawbacks; for instance, the elegant solution employed by OMI, a dual Babinet compensator pseudo-depolarizer, produced four slightly separated polarized beams that are difficult to compensate.
We propose to take the BATC time-domain polarization scrambler (TDPS), demonstrated under BATC funding, to a higher TRL. The TDPS uses high frequency polarization modulation to provide a large number of polarization cycles during a typical imaging integration time, producing a net null polarized beam. The laboratory demonstration unit will be further characterized and evolved, with the aim of incorporating a TDPS into an operating spectrometric system. The objective of the program is to produce a unit that is small and rugged enough to operate in a fieldable UV, Visible or Infrared spectrometer, the PolZero TDPS. A goal of the program is to use a TDPS-enhanced spectrometer in a mobile (possibly aircraft-based) Earth observation field measurement. The TRL of the TDPS will be advanced from TRL 3 (laboratory demonstration) to TRL 5 (demonstration in simulated operational environment) in a two year program.
The technology developed under this ACT program is relevant to UV/VIS spectrometers for ocean color and ozone measurements in particular and UV/VIS/NIR spectrometers and multi-spectral instruments in general. The depolarizer has application on GEOCAPE, GACM, HyspIRI, and ACE.
|Title||Hybridized Visible-NIR Blind (Al, In)GaN Focal Plane Arrays|
|Full Name||Scott Janz|
|Institution Name||Goddard Space Flight Center|
|We propose to design, build, test and evaluate against competing technologies, large format hybridized Al(In)GaN arrays with bandwidths adjusted to meet specific science needs for the next generation hyperspectral Earth remote sensing experiments called out in the National Research Council decadal survey(NRC, 2007). Specifically this technology would enhance the atmospheric sensor incorporated in the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission. Benefits will include stray light control(reducing the cost and complexity of the spectrograph design), ultra-low dark current noise to reduce cooling requirements, and much higher radiation tolerance compared to heritage technologies. The hybrid architecture will also provide higher dynamic range than standard back-thinned silicon arrays to meet signal-to-noise requirements in mixed cloudy/clear scenes.
Based on our successful experience in the design and build of a prototype 256×256 AlGaN array we will first scale this design up to a standard 1024×1024 18 um pixel pitch array appropriate for high spatial/spectral resolution sensors operating in the 270-365 nm range. We will then design and build a 1024×1024 InGaN array which will operate in the 365-480 nm range. Both focal planes will undergo full radiometric characterization and will be incorported into a laboratory spectrograph for demonstration and comparative testing. The period of performance of the proposed work is January 2009 to January 2012 with TRL maturation from level 2 to level 4.
Ultra-sensitive near-infrared optical receiver using avalanche photodiodes
Goddard Space Flight Center
Ultra-sensitive near-infrared optical receivers are required for active optical instruments. The NRC Earth science decadal lidar-based missions including ICESat2, DESDynI, LIST, ASCENDS, ACE, 3D-WINDS and Satellite Laser Ranging will all greatly benefit from high quantum efficiency, very low-noise (near single photon sensitive) optical receivers. Improvements in detector quantum efficiency translate directly to reduced laser energy requirements for active laser instruments. The combination of high efficiency and low-noise permits operation near the fundamental (quantum) limits. This minimizes spacecraft resource requirements (mass, power, volume). We propose to use InAlAs and InGaAs avalanche photodiode (APD) arrays packaged with multi-stage thermo-electric coolers to achieve very high quantum efficiency ultra-sensitive optical receivers. We will use very low-noise transimpedance amplifiers to achieve full high-bandwidth pulse waveform recovery from each pixel. We will demonstrate large arrays that will enable new lidar architectures.
This proposal is a collaboration between NASA Goddard Space Flight Center and Spectrolab Inc. Spectrolab will manufacture the avalanche photodiodes and configure and package the optical receiver The Spectrolab APD structures are based on the separate absorption and charge multiplication (SACM) structure: using InGaAs or InGaAsP as the absorber and either InP or InAlAs as the multiplication layer. The basic structure consists of the absorber layer with a relatively low electric field at operating bias to drift carriers in the proper direction, a multiplication layer with a high internal field which promotes impact ionization of the photocarriers, and a charge layer separating these two layers.
NASA Goddard Space Flight center will perform optical receiver testing and characterization for device design and parameter optimization.
|Title||Hybrid Doppler Wind Lidar Transceiver|
|Full Name||Cathy Marx|
|Institution Name||Goddard Space Flight Center|
|The 3D Tropospheric Winds mission is a high priority Earth Science mission identified by the National Research Council Decadal Survey. The recommended active optical instrument technology is a hybrid Doppler lidar which combines the best elements of a coherent aerosol Doppler lidar operating at 2 um and a direct detection molecular Doppler lidar operating at 0.355 um. The coherent and direct detection lidar techniques generally require different laser and Doppler receiver component technologies. One technology both systems need is a moderate aperture (0.5 m diameter) telescope assembly transceiver which transmits the pulsed laser energy and receives the backscattered laser return from the atmosphere. The science requires four separate fields of view. If the four fields of view are addressed with a single rotating telescope, there are significant power, mass and momentum compensation challenges. We propose a novel, compact, light weighted multi-field of view transceiver where multiple telescopes are used to cover the four fields of view. A small mechanism will sequentially select both the laser transmit and receive field of view. The four fields are combined to stimulate both the 0.355 um receiver and the 2 um receiver. We propose to build a scaled down version of the transceiver which will demonstrate the hybrid approach in a ground based test at the end of the third year. The primary mirrors will incorporate technology which is light weight and low-cost. This technology is suitable for other lidar applications and is especially attractive when multiple copies of identical mirrors are required. The TRL level for this dual wavelength, compact transceiver will advance from 2 to 4. The work is highly leveraged by previous investments of NASA, particularly by ESTO.|
|Title||Detector Technology Development for Cloud-Aerosol Transport Lidar|
|Full Name||Matthew McGill|
|Institution Name||Goddard Space Flight Center|
|Backscatter lidar is a proven useful tool for profiling the structure of atmospheric cloud and aerosol features. In addition to basic intensity information, backscattered photons inherently possess other microphysical attributes, such as Doppler shift caused by the mean motion of the scattering medium. Thus, a lidar system capable of resolving the Doppler shifts inherent to atmospheric motions can simultaneously provide information about both the scattering intensity and the particle motion.
We propose to construct and demonstrate an efficient, photon-counting detection system capable of simultaneously providing information about aerosol loading and motion. This detection system will ultimately become part of a lidar system for cloud-aerosol transport studies. In the long term, we want to construct and demonstrate a Cloud-Aerosol Transport System (CATS) lidar. The CATS lidar will be inherently a cloud-aerosol backscatter lidar but will also provide information on cloud and aerosol height, internal structure, and optical properties (e.g., optical depth). The added capability to derive wind motion will enable studies of aerosol transport and cloud motion. The technology developed will have direct application to future spaceborne missions, such as the proposed Aerosol-Cloud-Ecosystems (ACE) mission, and will provide critical validation capability for future missions. The technology also has potential application to the 3-D winds mission, but our focus is on the nearer-term ACE mission.
The basis for the detection system is a novel holographic optical element developed at NASA-Goddard. Previous investments from ESTO, SBIR, and Goddard IRAD will be leveraged to permit construction of a cost effective yet highly advanced detector subsystem suitable for future inclusion into a CATS lidar instrument. Our goal is to utilize future opportunities, such as the Instrument Incubator Program, to build the CATS aerosol-based lidar for use onboard a high-altitude aircraft to provide demonstration of both technology and measurements.
|Title||A GNSS RF ASIC For Digital Beamforming Applications|
|Full Name||TK Meehan|
|Institution Name||Jet Propulsion Laboratory|
|We will design and build a GNSS (GPS + Galileo+ GLONASS) Multi-frequency Radio Frequency (RF) Hybrid Application Specific Integrated Circuit (ASIC). The objective is to develop a compact low-power radiation resistant component that can be applied to wide ranging remote sensing applications such as atmospheric occultations, ocean reflections and ionospheric soundings. Future GNSS instrumentation will require RF processing at three frequencies; L1 (1575 MHz) L2 (1227 MHz) and L5 (1175 MHz) with many antennas. Each instrument will employ many RF processors for applications where high-gain observations are required. Our GNSS RF ASIC will allow these future systems to be constructed compactly, using much less power and mass than present technology allows. JPL will work closely with an industrial partner for this development effort. High-level design processing functions, specific frequencies and radiometric performance parameters will be defined by the PI and JPL engineers.|
|Title||Far-Infrared Extended Blocked Impurity Band (FIREBIB) Detectors Optimized for Earth Radiance Measurements|
|Full Name||Martin Mlynczak|
|Institution Name||Langley Research Center|
|We propose to demonstrate at TRL 5 new far-infrared (far-IR) detectors applicable to the CLARREO mission defined by the recent Decadal Survey for Earth Science. The CLARREO mission requires accurately calibrated measurements of the spectral radiance from the Earth and its atmosphere from 5 to at least 50 micrometers (um) in wavelength. Extant detector technology for the far-IR (15 to 50 um) consists primarily of low sensitivity devices operating at ambient temperatures or high sensitivity devices that require cooling to liquid helium temperatures. We propose to extend a recent and successful NASA Advanced Technology Initiative award (ATI-QRS-06-3001) in which a new far-IR detector type was demonstrated. The new detector operates at temperatures accessible by existing space-qualified cryocoolers with very high sensitivity, high stability, high linearity, and large bandwidth, and therefore merits serious consideration for the CLARREO mission.
The proposed Far-Infrared Extended Blocked Impurity Band (FIREBIB) detectors are an extension of the well-known class of silicon BIB detectors for the mid-infrared. We will extend the wavelength into the far-IR to at least 50 um (goal 100 um) using the recently demonstrated approach. We will also adapt a detector design and light-trapping detector packaging from another recent detector program to achieve the following target performance levels from 10 to 50 um (with 100 um goal): (i) Unity gain; (ii) Bandwidth > 100 kHz suitable for the CLARREO Fourier transform spectrometer instruments; (iii) Quantum Efficiency (QE) > 99.9% in a trap detector configuration; (iv) Specific Detectivity > 1e+10 cm sqrt(hz) /W (goal > 1e+11 cm sqrt(hz)/W); (v) QE stability against temperature and radiation effects; (vi) Nominal Detector Area (trap acceptance area) of 200 x 200 µm2. These enhancements in detector performance will enable improvements in overall system performance in terms of increased radiometric accuracy, reduced spatial smearing, and simpler calibration approaches for CLARREO.
|Title||CLASS Instrument Technology Maturation for ASCENDS|
|Full Name||Mark Phillips|
|Institution Name||Lockheed Martin Coherent Technologies|
|Lockheed Martin (LM) and JPL propose to jointly advance the technology readiness of the existing state-of-the-art 2-µm coherent CO2 Laser Absorption Spectroscopy Sensor (CLASS) instrument, now proven by multiple airborne campaigns, for consideration on the ASCENDS mission recommended by the 2007 NAS Earth Science Decadal Survey. ESTO funding under JPL’s IIP 2002 award enabled us to advance the CLASS instrument from concept to successful airborne flights that continue today. Under ACT funding we propose to reduce the primary technical obstacle facing the ASCENDS mission sensor, by traceably advancing our laser transmitter optical power output by a factor of 50, from the 100mW used now in our airborne prototype to the 5W we estimate as needed for CLASS to measure CO2 through the PBL at <2ppmv from space on ASCENDS.
We accomplish this component technology advance in two steps. First we demonstrate 5W laser transmitter output power in the lab, cost-effectively leveraging an existing LM commercial METEOR® 2-µm single frequency laser, proven 2-µm COTS fiber amplifier technology, and LM’s high-precision frequency control technology. Then we demonstrate 5W transmitter output power again, but featuring the <1MHz absolute frequency locking that we demonstrated in the airborne prototype and that is needed to meet required CO2 measurement precision on ASCENDS. Secondary objectives include advancing space readiness of a few critical components unique to the CLASS instrument by completing space environment characterization testing, as well as refinement of our point-of-departure instrument design and performance model predictions for CLASS manifested on ASCENDS.
We advance CLASS instrument space-readiness from TRL3+ to TRL4 in year 2 and to just shy of TRL5 in year 3. As a result, we ready CLASS as a leading candidate sensor for ASCENDS, featuring non-cryogenic detectors, broad optical pump bands, relaxed thermal rejection needs, all-fiber amplifier assembly, and integrated pump diode redundancy.
|Title||Advanced Component Development to Enable Low-Mass, Low-Power High-Frequency Radiometers for Coastal Wet-Tropospheric Correction on SWOT|
|Full Name||Steven Reising|
|Institution Name||Colorado State University|
|We propose to develop and demonstrate three component technologies that are critical to reduce the risk, cost, volume, mass, and development time for the high-frequency microwave radiometer needed to enable a wet-tropospheric correction in the coastal zone on the NRC Decadal Survey-recommended Surface Water and Ocean Topography (SWOT) Mission. Development of a new high-frequency radiometer measurement technique for SWOT requires technology development in the following two key areas: (1) the development of a low-power, low-mass and small-volume direct-detection millimeter-wave receiver with integrated calibration sources covering frequencies from 90 to 170 GHz that fits within the overall SWOT mission constraints, and (2) a multi-frequency feed horn covering the same frequency range. To accomplish these objectives, we propose essentially to scale the design of the Advanced Microwave Radiometer (AMR) that is currently flying on the OSTM/Jason-2 altimetry mission. The MMIC-based AMR receiver combines three channels at 18.7, 23.8 and 34.0 GHz into a single unit with a single multi-frequency feed horn. This proposed ACT program will address the development of the following three key component technologies needed to scale the AMR receiver design: a PIN-diode switch for calibration that can be integrated into the receiver front end, a high-Excess Noise Ratio (ENR) noise source and a multi-frequency feed horn. These new components will be integrated into a MMIC-based low-mass, low-power, small-volume radiometer at 92, 130 and 166 GHz. This radiometer will serve as a breadboard demonstration, providing realistic mass, volume and power estimates to feed into the mission concept study. The entry TRL for the high-ENR noise sources above 100 GHz and MMIC PIN-diode switch is 2, and they will have an exit TRL of 4. The entry TRL for the multi-frequency feed horn and MMIC-based direct detection, LNA-front end receivers above 100 GHz is 3 with an exit TRL of 4.|
|Title||In-Pixel Digitization Read Out Integrated Circuit for the Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission|
|Full Name||David Rider|
|Institution Name||Jet Propulsion Laboratory|
|We will demonstrate a high performance read out integrated circuit (ROIC) with an innovative analog-to-digital converter in-pixel that works with the broad class of detectors commonly used to make earth science measurements in the ultra-violet to mid-infrared wavelengths. Our in-pixel digitization approach provides several benefits including substantial reductions in instrument size, mass, power, and accommodation cost, while simultaneously achieving significantly higher performance (high-speed, high-resolution, and low power). Faster frame rates due to the greatly parallelized flow of detector signals enable greater temporal, spectral and spatial coverage for imaging spectrometers. Signal-to-noise is also improved by eliminating the need to send analog signals over long wires to transfer the detector signal to off-chip digitizers. This high-speed, high resolution read out capability for imaging spectrometers will benefit several Decadal Survey missions including GEO-CAPE, GACM, ACE, and HyspIRI, by significantly improving their capability to measure earth’s rapidly changing geophysical characteristics.
An innovative in-pixel current-to-frequency digitization approach will be demonstrated using conventional 0.35 um process circuit design tools proven to successfully develop similar circuits. The resulting 128×128 ROIC design will be fabricated by a commercial foundry and the chips produced will be tested in the JPL CMOS Image Sensor development labs.
To demonstrate ROIC performance in a relevant environment (i.e. an imaging spectrometer), final testing will be done by substituting our ROIC for the detector in the Fourier Transform UV/Vis Spectrometer (FTUVS) at JPL’s Table Mountain Facility which is an operational instrument, routinely measuring total column abundances of OH, NO2, NO3, CO2, BrO and other species. Comparing the ROIC spectra with those normally produced by FTUVS, will demonstrate the utility of the ROIC for atmospheric composition measurements called for in the Decadal Survey.
A three year effort will advance ROIC technology from the current TRL level 2, to the planned exit level of TRL 5.
|Title||A Low Power, High Bandwidth Receiver for Ka-band Interferometry|
|Full Name||Paul Siqueira|
|Institution Name||University of Massachusetts|
|One of the Decadal Survey’s identified missions for the 2013-2016 timeframe is the Surface Water and Ocean Topography (SWOT) mission for measuring sea level and river stage height at a higher spatial resolution and over a wider swath than what is currently available through more traditional altimetric methods. One of the key technologies that will be used for achieving these unprecedented accuracies and spatial coverages will be the implementation of a near-nadir looking Ka-band (35 GHz) interferometer. Implementation of an interferometer at these frequencies allows for a compact spaceborne structure and a high bandwidth (200 MHz), and therefore a high resolution. A challenge that is associated with the use of these high frequencies however is the construction of a high phase and amplitude stable receiver that is capable of making the precision measurements of the received RF signals over this wide bandwidth. As such, two candidate approaches can be used for achieving these performance specifications. One is to use two stages of downconversion to get to baseband, which can then be digitally sampled and fed into an FPGA for noise bandwidth filtering and thermal compensation. The other is to perform direct sampling at an L-band intermediate frequency, and to digitally perform the downconversion, filtering and thermal compensation. While the two-stage downconversion approach is more straight-forward, the large fractional bandwidth that the signal occupies at baseband is likely to be affected more by thermally sensitive variations across the bandpass, especially near the band edges. Conversely, the direct sampling approach, provides considerably more design flexibility but at the cost of higher power. Between these two approaches lies a trade-space which can be explored to find the best solution to the interferometer’s need of a high precision, high bandwidth two-channel receiver for the SWOT mission.
In the work described in this proposal, we will explore these two alternative approaches through the construction of a Ka-band receiver with implementations of both direct and two-stage downconverted signals, and provide metrics of power and performance as a function of the design spaces. The final product will be directly integrable into the overall SWOT instrument architecture.
|Title||Large Aperture, Solid Surface Deployable Reflector|
|Full Name||Robert Taylor|
|Institution Name||Composite Technology Development|
|For NASA to provide the necessary information regarding climate change, weather forecasting, and disaster relief, near-term and future NASA Earth Science missions will require sensors with the capability of providing increased amounts of data, including higher rates and densities, as well as to be capable of measuring multiple variables and signals to provide a more integrated view of the Earth system. As stated in the 2008 NASA ROSES ACT solicitation, “technologies enabling large deployable Ka-band or higher spaceborne reflectors for Decadal Survey missions/measurements” are a high priority. The TEMBO® solid-surface deployable reflectors being developed by CTD exactly meet this need. These reflectors will be lower cost than current deployable reflectors and appear to meet the needs of a variety of missions, including SMAP, SWOT, XOVWM, PATH and SCLP.
Under the proposed program, Composite Technology Development (CTD) will develop a 6 meter deployable solid surface offset fed reflector capable of Ka-band and higher frequencies. A 4 meter engineering unit will be designed, developed and fabricated to demonstrate this technology. This 4 meter engineering unit will be used to demonstrate Ka-band performance and deployment repeatability for an offset fed reflector representing relevant surface contour using available tooling.In summary, this program will advance CTD’s solid surface, offset-fed, deployable reflector technology from a TRL 2 to a TRL 5, enabling the delivery of the first flight-ready reflector within 12 months of the completion of this proposed program and within 9 months on future programs for 25% of the projected cost of a similar mesh reflector. This family of 6+m reflectors will be compatible with many Decadal Survey missions.
|Title||Large Deployable Ka-Band Reflectarray For The Swot Mission|
|Full Name||Mark Thomson|
|Institution Name||Jet Propulsion Laboratory|
|The Jet Propulsion Laboratory (JPL) proposes to design and build an integrated prototype structure and mechanism system to deploy a large Ka-Band reflectarray for use in synthetic aperture radar, wide-swath altimetry, such as the Surface Water and Ocean Topography (SWOT) mission, one of the missions recommended for implementation by NASA by the NRC decadal review report. A stable platform on which to mount the reflectarray is a critical component of a mission that aims to provide critical knowledge about the land surface water and ocean mesoscale and submesoscale processes on Earth And successful completion of this task will significantly mitigate the risks associated with providing that stable platform on which to mount the reflectarray.
A stable platform for the arrays is a critical part of making a radar-mapping mission successful, since the SWOT instrument requires tight pointing requirements and stability in order to meet its mission goals. These requirements can be met in part by minimizing the equipment on the ends of the interferometric mast, but significant challenges remain in designing a stiff, stable antenna deployment structure that can package down into a small space for launch.
Over a period of three years, this task will develop the requirements needed to build a prototype of the deployment mechanism, then design, build, and test the mechanism. This will be done in stages; starting with analysis and design to raise the TRL and understanding in one year, followed by a two year build and test to further raise the TRL level. In addition, valuable models will be created to predict the performance of such a system when the flight unit is built. Building upon the experience of previous work, such as the Wide-Swath Ocean Altimeter (WSOA), this task will move the TRL of the device from level 2 to level 4.