National Aeronautics and Space Administration
Small Business Innovation Research 2001 Program Solicitation

TOPIC E1 Instruments for Earth Science Measurements

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E1.01 Passive Optical
E1.02 Active Optical
E1.03 In Situ Terrestrial Sensors
E1.04 Passive Microwave
E1.05 Active Microwave
E1.06 Passive Infrared - Sub Millimeter
E1.07 Thermal Control for Instruments

NASA's Earth Science Enterprise is studying how our global environment is changing. Using the unique perspective available from space and airborne platforms, NASA is observing, documenting, and assessing large-scale environmental processes, with emphasis on biology and biogeochemistry of ecosystems and the global carbon cycle, global water and energy cycle, climate variability and prediction, atmospheric chemistry, and solid Earth and natural hazards. A major objective of the ESE instrument development programs is to implement science measurement capabilities with small or more affordable spacecraft so that the development programs can meet multiple mission needs and therefore make the best use of limited resources. The rapid development of small, low cost remote sensing and in situ instruments is essential to achieving this objective. Consequently, the objective of the Instruments for Earth Science Measurements SBIR topic is to develop and demonstrate instrument component and subsystem technologies which reduce the risk, cost, size, and development time of Earth observing instruments, and enable new Earth observation measurements. The following subtopics are concomitant with this objective and are organized by measurement technique.

E1.01 Passive Optical
Lead Center: LaRC
Participating Center(s): ARC, GSFC

Proposals are sought for the development of innovative technology for measuring the atmosphere and Earth surface using passive optical techniques. The innovations are intended to increase our understanding of the interacting physical, chemical and biological processes that form the complex Earth system.

Atmospheric measurements of interest include climate and meteorological parameters, such as temperature, amounts of aerosols, clouds, water vapor, carbon dioxide and methane; and, chemical constituents such as ozone, nitrogen dioxide, nitric oxide, carbon monoxide, and hydrocarbons. Surface measurements of interest include vegetation index, multi-spectral imaging, bi-directional reflectance, biological productivity, surface terrain mapping, temperatures of water, land and ice, ocean productivity and ocean color. Technology innovations may include components, subsystems, and complete systems and should address reduced size, weight or power, improved reliability and lower cost. The wavelengths of interest include IR, visible and ultraviolet bands. The innovations should expand the capabilities of airborne systems (manned and unmanned) and the next generation spaceborne systems. Innovative approaches are an important element of competitive proposals under this solicitation. Specific needs include:

System Architectures

• Innovative instrument architectures that provide flexibility in system configuration to address specific measurement requirements. For example, sampling flexibility in either the spectral or spatial domain of an imaging spectrometer focal plane array will provide the ability to trade between spectral and spatial resolution in the context of a specific scientific problem as constrained by limited downlink bandwidth.
• Innovative instrument architectures that expand scientific knowledge and provide significant reductions in the end-to-end implementation. This includes designs and component technologies relating to improved sensors for observations Earth's surface and atmosphere. Examples of instruments include multi-spectral imaging radiometers and flux radiometers for wavelengths from the UV to microwave. Innovative measurement concepts or advances leading to smaller and lower cost instruments will be considered. Technical approaches should include application of un-cooled infrared detectors, non-mechanical choppers, calibration methods and tuned filters.
• High throughput compact systems (f/1-f/2).
• Wide field of view spectrometer systems (e.g., with expandable architectures) with no moving parts.
• Systems with inherent environmental stability.

Component Technologies

• Optical technologies that will enable high spatial resolution (< 10 meter) measurements along track for spacecraft sensors in low Earth orbit. Combinations of high light collection efficiency and instrument throughput, and fast, low noise detector readout are required to provide adequate signal power (SNR > 500) to address multi- and hyper-spectral measurement requirements.
• Wedge filters suitable for space application and capable of spectral resolutions of a few nano-meters over the visible through short-wave IR portions of the spectrum, and angular (IFOV) resolutions on the order of a milli-radian.
• 4 K x 4 K and larger detector arrays sensitive in near UV (300-400 nm) and Near IR (1-3 micron) with large (> 1 million electrons) well depth.
• Ultra-stable spectral calibration techniques for data quality management and the evaluation of long-term sensor degradation trends in space instruments.
• On-board, near real-time processing for atmospheric correction, geo-location, and geometric correction of digital image data.
• Optical imager technologies that will enable lightweight, low cost large aperture optical systems optics for a variety of land, ocean, and atmospheric observations through the elimination of conventional telescopes and focal planes in space based imagers. For example, phased arrays or multi-spectral imagers based on holographic and/or diffractive optics. Instruments should have performance specifications comparable to or better than current imagers such as MODIS aboard NASA's Terra satellite.
• Fast, 1-meter diameter lightweight telescope for space application with minimal distortion in the 0.3- 3-micron wavelength range.
• Ultra-stable remote sensor calibration techniques for long-term trend determination in space instruments.
• Development of innovative techniques and component technologies for measuring polarization of light scattered from the atmosphere.
• Advanced gratings on flat or curved surfaces that maximize efficiency and minimize scatter and ghosts.
• Linear variable filters with extended range, seamlessly stitched filter strips.
• Broadband antireflection methods that can be applied to the photodetector array, in the visible and infrared.
• Novel or improved high-resolution dispersive elements.
• Environmentally robust, electronically variable filters with extended spectral range.

Innovative Optomechanical Designs

• Development of systems capable of off-nadir pointing for the acquisition of multi-angle data, the acquisition of stereo pairs, the frequent imaging of rapidly changing events from orbit scanning and tilting to remove sun reflection off the ocean, and the frequent imaging of rapidly changing events from orbit. Very low mass, power and high speed and flexibility are desired.
• Compact, lightweight optical designs that utilize a minimum number of optical surfaces.
• Non-classical designs utilizing guided wave optics.
• Self-aligning systems or methods of assembly.

E1.02 Active Optical
Lead Center: LaRC
Participating Center(s): JPL, GSFC

Innovative developments are needed in lidar technology for the remote measurement of atmospheric aerosols, clouds, molecular species (ozone, water vapor, carbon monoxide, carbon dioxide, methane, and nitrous oxide), meteorological parameters (density, pressure, temperature, and wind profiles), planetary surface topography, vegetation, and sub-surface ocean layers; for ground-based lidar systems and laser ranging systems that measure atmospheric backscatter, vegetation structure and composition, and pulse time-of-flight to laser transponders or reflectors on satellites. Specifically, technologies for expanding the measurement capabilities of current airborne lidar systems and for the next generation of spaceborne and Unmanned Aeronautical Vehicle (UAV) lidar systems are sought. Technology innovations may include lidar components, subsystems, and complete systems and may address reduced weight or power or increased energy efficiency, reliability, or autonomous operation.

Atmospheric Constituent Measurements

• Solid-state laser technology for tunable and/or fixed frequency, high-energy (> 500 mJ at more than 10 Hz) pulsed lasers for spaceborne applications. This includes solid-state laser materials compatible with diode pumping and high efficiency (> 2.5 percent wallplug) and new or improved optical materials for high efficiency frequency conversion. Of prime interest are long-lifetime, low weight and volume materials and technologies applicable to highly efficient, conductively cooled lasers operating in the 0.28-0.36, 0.47-0.54, 0.7-1.1, and 1.5-2.8 micron regions; also interested in the 3.2-4.7 micron region. Also needed are single-mode, line-narrowed, compact sources for injection seeding in the 0.28-0.36, 0.7-1.1 and 1.5-2.1 micron regions and high reliability, high efficiency, high brightness, conductively cooled diode arrays operating in wavelength regions for pumping solid-state lasers.
• Lidar receiver technology for large (> 3m²), lightweight collection apertures having multiple-wavelength operation from UV to near IR is needed. Inherent spectral selection/dispersion and high peak transmission (50-80 percent), electromagnetically tuned, narrow bandwidth (10-100 pico-meters) filtering is desirable. Small- and large-angle scanning (up to 3 degrees and 30-60 degrees off nadir, respectively) of 0.5 meter and 1.0 meter lidar systems is needed for space. Low mass and few to no moving parts.
• Signal detection and processing subsystems with quick recovery (less than 3 microseconds) from saturation and high-speed, high-quantum efficiency (30-80 percent) detectors with low-noise and good linearity are needed for lidar operation over large dynamic ranges.
• For UAV applications, compact, high repetition rate, narrow line-width laser transmitter systems are needed that produce energies from micro- to milli-Joules per pulse. Laser energies of more than 100 mJ at 30-1000 Hz in the UV and more than 200 mJ at 10-20 Hz in the 355, 936, 944, and 1064 nm region are needed.
• High CW power (> 500 mW - 1 W) single spatial mode laser diodes, based on simplistic structures such as the Fabry-Perot cavity, for core-pumping of fiber lasers. Wavelength regions mainly include 800-810 nm, but also of interest are 780-785 nm, and 980 nm.
• Single-element and array detectors, combined with preamplifier circuitry in a single integrated circuit, for lidar detection at 355nm, 532nm, and 1064nm having several giga-hertz bandwidth, high quantum efficiencies, good linearity, and minimum cooling requirements.
• Optical phased array scanning concepts for programmable beam pointing with high transmission (> 90 percent) and angular deflection capability > 20 degrees. Aperture diameters from 2 cm to 1 m are of interest and preservation of beam quality is a primary requirement.
• Large aperture, ultra light, scanning lidar receivers with high efficiency, narrow field-of-view, and narrowband filtering.
• Scanning lidar transceivers that use aperture sharing and are capable of producing multiple look angles, each with a small field-of-view.

Coherent Wind Measurements in the 1.5-2.5 Micrometer Wavelength Range

• Low mass, compact optics for deflecting a circularly polarized laser beam for a conical scan. Diameters of 5 cm to 1 m with an immediate need of up to 50 cm. Preservation of laser beam quality is required.
• Low mass, 1-m class beam expanding telescope technology with low fabrication cost and long-lived performance in space environment.
• Technology for autonomous operation and alignment maintenance of coherent lidar systems; such as a low-mass, low-power, low-voltage optical element capable of correcting piston, defocus, astigmatism, coma, and spherical aberrations.
• Integrated opto-electronic receiver combining photodetectors, local oscillator laser, beam conditioning and combining, and signal processing components.
• Fast (few tens of microseconds) lag-angle compensation optics technology for precise, reliable steering of the optical axis of a space-based Doppler lidar.
• Single-element and array detectors having high bandwidth, high quantum efficiencies in the 1.5-2.5 micron wavelength band. Bandwidths up to 6 GHz are desired.
• Pulsed, eye safe laser technology having technical path leading to simultaneous characteristics of > 2J energy, > 12 Hz PRF, < 500 W laser power requirement when pulsing, < 2 microsecond duration, < 1 m/s equivalent pulse spectrum, < 1.3 m² beam quality, intermittent operation with periods of 1-10 minutes and duty cycle around 20 percent and minimum "off" power draw and minimum time to restabilize, and which shows potential for 7-year lifetime in space environment.
• Diode-laser arrays operating near 0.79 micrometers having pulse lengths > 1.0 ms, energy densities > 1.3 J/cm², duty cycle > 0.20 and narrow beam divergence.
• High efficiency methods for concentrating the emissions from nominal 1.0 cm square arrays to 4.0 mm diameter spot sizes.
• Tunable single-mode semiconductor lasers or other compact, single frequency sources for use as injection seeders and/or local oscillators, with linewidths 0.1-0.2 MHz operating in the 1.8-2.2 micron and 3.0-3.5 micron regions.

Surface Topography and Oceanic Measurements

• Compact, conductively-cooled, near-infrared laser transmitters with less than 1 nsec pulses, single spatial mode, several milli-joule performance at multi-kilohertz pulse rates.
• Oceanic LIDAR systems or components in the 480-685 nm wavelength region for remote sensing of subsurface ocean layers and fluorescence.
• Quadrant Geiger-mode avalanche, photo diodes or comparable micro-channel plate photomultipliers with a quantum efficiency approaching 40 percent @ 532 nm, less than or equal to 400 psec risetime, and submicro-second gating at 2 kHz rates.
• Silicon avalanche photo diodes, photodiode arrays, and photon counting detectors with quantum efficiency greater than 35 percent at 1064 nm wavelength; and high efficiency, high speed, and low noise detectors for the 1500 to 2200 nm wavelength region.
• Signal detection and processing subsystems with quick recovery (less than 30 micro-sec) from saturation and high-speed, high-quantum efficiency (30-80 percent) detectors with low noise and good linearity are needed for lidar operation over large dynamic ranges.

Direct Detection and Other Measurements

• Laser techniques and component technology for measurement of the wind field and wind shear using direct-detection methods, with high accuracy and high range resolution. Eye safety is a consideration.
• High spectral resolution filters with high throughput, out of band spectral blocking, frequency tunable, and frequency stabilization for direct-detection measurements of winds at 355 nm (1 GHz bandwidth) and 1064 nm (100 MHz bandwidth).
• Compact, power efficient, frequency reference with better than 1 part in 10¹⁴ stability and accuracy; that is suitable for interplanetary missions.
• Adaptive photon-counting correlation range receivers capable of extracting satellite range data with high time resolution (better than 20 psec) during daylight operations.
• High detectivity, spectrally diverse receivers including narrowband notch filters, high transmission narrow bandpass optical filters, and multi-channel array detection.

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E1.03 In Situ Terrestrial Sensors
Lead Center: GSFC
Participating Center(s): ARC, JPL

Proposals are sought for the development of in situ measurement systems that will enhance the scientific and commercial utility of data products from the Earth Science Enterprise program and that will enable the development of new products of interest to commercial and governmental entities around the world. Technologies of interest include:

• Autonomous GPS-located ocean platforms to measure and transmit to remote terminals upper ocean and lower atmosphere properties including temperature, salinity, momentum, light, precipitation, and biology. Similar sensor packages for use onboard ships while under way.
• Autonomous low-cost systems to measure surface and lower atmospheric parameters including soil moisture, precipitation, temperature, wind speed and humidity.
• Small, lightweight instruments suitable for balloons, kites, or small remotely piloted aircraft for in situ measurements of atmospheric trace gasses and cloud radioactive properties including extinction, absorption, scattering phase function and phase function asymmetry.
• Wide-band microwave radiometers capable of high-speed characterization of cloud parameters, including liquid and ice phase precipitation, that can operate in harsh environmental conditions (e.g., on-board ships and aircraft).
• Autonomous GPS-located airborne sensors that remotely sense atmospheric wind profiles in the troposphere and lower stratosphere with high spatial resolution and accuracy.
• Systems and devices for measurement of atmospheric aerosol chemical, microphysical, and radioactive properties. Autonomy is desired for ground-station network applications and deployment aboard aircraft.
• Lightning location techniques to locate VLF sferic sources (5 to 15 kHz) within 100 km at ranges of 2000 km or more.
• Systems for in situ measurement of atmospheric electrical parameters including electric and magnetic fields, conductivity, and optical emissions.
• Systems to measure line- and area-averaged rain rate at the surface over lines of at least 100 meters and areas of at least 100x100 meters.
• Lightweight, low-power systems that integrate the functions of inertial navigation systems and GPS receivers for characterizing the flight path of remotely piloted vehicles.
• Low-cost, stable (< 1 percent over several months) portable radiometric sources for field characterization of spectral radiometers.
• Innovative approaches for the gathering, storing, and forwarding of in situ measurements using common carrier infrastructures.
• Mass spectrometer time-of-flight system with: (1) weight < 1kg, (2) dynamic range > 10⁸, (3) a mass range of 1 - 2000 amu with unit resolution throughout, and (4) innovative ionization techniques with an order of magnitude improvement over current sources.
  

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E1.04 Passive Microwave
Lead Center: GSFC
Participating Center(s): JPL

Proposals are sought for the development of innovative passive microwave technology in support of Earth System Science measurements of the Earth's atmosphere and surface. These microwave radiometry technology innovations are intended for use in the microwave frequency band from, principally about 1 to 300 GHz, but also with applications outside that band. The key science goal is to increase our understanding of the interacting physical, chemical and biological processes that form the complex Earth system. Atmospheric measurements of interest include climate and meteorological parameters, including temperature, water vapor, clouds, precipitation, aerosols; air pollution; and chemical constituents such as ozone, NOX, and carbon monoxide. Earth surface measurements of interest include water, land and ice surface temperatures, land surface moisture, snow coverage and water content, sea surface salinity and winds, and multi-spectral imaging.

Technology innovations are sought that will provide the concepts, components, subsystems, or complete systems to improve Earth System Science measurements. Technology innovations should address enhanced measurement capabilities such as improved spatial or temporal resolution, spectral resolution, or calibration accuracy. Technology innovations should provide reduced size, weight, power, improved reliability and lower cost. The innovations should expand the capabilities of airborne systems (manned and unmanned) as well as next generation spaceborne systems. Highly innovative approaches that open new pathways are an important element of competitive proposals under this solicitation. Specific technology needs include:

• Imaging radiometers, receivers or receiver arrays on a chip, and flux radiometers for microwave wavelengths (1 - 500 GHz).
• Large aperture, deployable antenna systems suitable for highly reliable space deployment with RMS surface accuracy of ~ 1/50th wavelength. Such large apertures can be real or synthetic apertures. Of key importance is the ability for a highly compact launch configuration, followed by a highly reliable erection and resultant surface configuration. Novel approaches to beam steering for these very large aperture antenna systems are also desired.
• On-board data processing capabilities that enable real-time, re-configurable computational approaches that enhance research flexibility. Such approaches should improve image reconstruction, enable high compression ratios; improve atmospheric corrections and the geo-location and geometric correction of digital image data.
• Techniques for the detection and removal of Radio Frequency Interference (RFI) in microwave radiometers are desired. Microwave radiometer measurements can be contaminated by RFI that is within or near the reception band of the radiometer. Electronic design approaches and subsystems are desired that can be incorporated into microwave radiometers to detect and suppress RFI, thus insuring higher data quality.
• New technology calibration reference sources for microwave radiometers that provide greatly improved reference measurement accuracy. High emissivity (near block-body) surfaces are often used as onboard calibration targets for many microwave radiometers. NASA seeks ways to significantly reduce the weight of aluminum core target designs, while reliably improving the uniformity and knowledge of the calibration target temperature. NASA seeks innovative new designs for highly stable noise-diode or other electronic devices as additional reference sources for onboard calibration. Of particular interest are variable correlated noise sources for calibrating correlation-type receivers used in aperture synthesis and polarimetric radiometers.
• New approaches, concepts and techniques are sought for microwave radiometer system calibration over or within the 1 -300 GHz frequency band, that provide end-to-end calibration to better than 0.1 K, including corrections for temperature changes and other potential sources of instrumental measurement drift and error.
• Focal plane array modules for large-aperture passive microwave imaging applications.
• High power (> 5 mW) signal sources and low noise (< 500 K) heterodyne receivers for operation above 100 GHz.
• Multi-GHz. Low power, 4-bit under-sampling analog-to-digital converters and associated digital signal processing logic circuits.
• Low power lightweight microwave radiometers are desired that are able to operate stably over long periods, with DC power consumption of less than 2 W and preferably less than 1 W, not including any mechanisms.
• MMIC LNA for spaceborne microwave radiometers, covering the frequency range of 165 to 193 GHz, having a noise figure of 6.0 dB or better (and with low 1/f noise).
• NASA is developing satellite systems that will use passive and active microwave sensing at L-band and other frequencies to measure sea surface salinity, and soil moisture to a depth of ~ 10 cm. In support of these global research efforts, the following ancillary measurement systems are required:
• Inexpensive approaches to ground sensors are desired that are capable of measuring areas at least 100,000 km², with spatial resolution of 20 km. These ground sensors will be needed to validate those space-borne measurements. Measurement of ground-wave propagation characteristics of radio signals from commercial sources may satisfy that need. Although absolute values of soil moisture are desirable, they are not required if the technique can be calibrated frequently at suitable sites. Cost per covered area, autonomous operation, anticipated accuracy and depth resolution of the soil moisture measurement will be considerations for selection.
• Autonomous GPs-located ocean platforms are needed that can measure upper ocean and lower atmosphere properties including temperature, salinity, momentum, light, precipitation, and biology, and can communicate the resultant data and computational or configuration instructions to and from remote terminals. Similar sensor packages are desired for use onboard ships while under way. This includes the development of intelligent platforms that can change measurement strategy upon receipt of a message from a command center.
• Autonomous low-cost systems are desired that can measure Earth and ocean surface and lower atmospheric parameters including soil moisture, precipitation, temperature, wind speed, sea surface salinity, surface irradiance and humidity.
  

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E1.05 Active Microwave
Lead Center: JPL
Participating Center(s): GSFC

Active microwave sensors have proven to be ideal instruments for many Earth science applications. Some examples include global freeze/thaw monitoring and soil moisture mapping, accurate global wind retrieval and snow inundation mapping, global 3-D mapping of rainfall and cloud systems, precise topographic mapping and natural hazard monitoring, global ocean topographic mapping and glacial ice mapping for climate change studies. For global coverage and the long-term study of Earth's ecosystems, space-based radar is of particular interest to Earth scientists. Radar instruments for Earth science measurements include Synthetic Aperture Radar (SAR), scatterometer, sounder, altimeter and atmospheric radar. The life-cycle cost of such radar missions has always been driven by the resources - power, mass, size, and data rate - required by the radar instrument, often making radar not cost competitive with other remote sensing instruments. Order-of-magnitude advancement in key sensor components will make the radar instrument more power efficient, much lighter in weight and smaller in stow volume, leading to substantial savings in overall mission life-cycle cost by requiring smaller and less expensive spacecraft buses and launch vehicles. On-board processing techniques will reduce data rates sufficiently to enable global coverage. High performance yet affordable radars will provide data products of better quality and deliver them to the users in a more timely and frequent manner with benefits for science, as well as civil and defense communities. Technologies which may lead to advances in instrument design, architectures, hardware, and algorithms are the focused areas of this subtopic. In order to increase the radar remote sensing user community, this subtopic will also consider radar data applications and post processing techniques.

The frequency and bandwidth of the operation are mission driven and defined by the science objectives. For SAR applications, the frequencies of interest include L-band (1.25 GHz), C-band (5.30 GHz), and X-band (9.6 GHz). The required bandwidth varies from 20 MHz to 300 MHz to achieve the desired resolution. The application of the synthetic aperture technique is also applied to other radars, including radar ice sounding and wide swath ocean altimeters. The sounder is a low frequency radar (< 100 MHz) with a very high percentage bandwidth (100 percent). The atmospheric radars operate at very high frequencies (35 GHz and 94 GHz) with only modest bandwidth requirements on the order of a few MHz. Ocean altimeters typically operate at L-band (1.2 GHz), C-band (5.3 GHz) and Ku-band (12 GHz).

The emphasis of this subtopic is on core technologies that will significantly reduce mission costs and increase performance and utility of future radar systems. Specific areas in which advances are needed include:

Synthetic Aperture Radar

• Lightweight, electronically steerable, dual-polarized, phased-array antennas
• Very large aperture antennas (50 m x 50 m) for geosynchronous SAR applications
• Shared aperture, multi-frequency antennas
• Lightweight deployable antenna structures and deployment mechanisms
• High-efficiency, high power, low-cost, lightweight, phase-stable transmit/receive modules
• Advanced transmit/receive module architectures such as optically fed T/R modules, signal up/down conversion within the module and novel RF and DC signal distribution techniques
• Advanced radar system architectures including flexible, broadband signal generation and direct digital conversion radar systems
• Advanced antenna array architectures including scalable, reconfigurable and autonomous antennas; sparse arrays; digital beamforming techniques; time domain techniques; phase correction techniques
• Innovative radar system concepts to achieve wide swath (> 250 km) to enable frequent site revisit and ultra-low-cost radars to enable constellations for global coverage
• Advanced radar component technologies including high-power low-loss RF switches, filters and phase shifters (MEMS devices are of particular interest); thin-film membrane compatible electronics, high-efficiency power converters; high-speed analog-to-digital converters; low-sidelobe chirp waveform generators and optical chirp generators
• Distributed digital beamforming and onboard processing technologies
• SAR data processing algorithms and data reduction techniques
• SAR data applications and post-processing techniques

Radar Ice-Sounder

• Synthetic aperture processing technique to increase resolution
• Lightweight broad-band (100 percent or more) low frequency (< 100 MHz), high gain (> 10 dB) deployable antennas
• Highly efficient, broadband, low frequency (< 100 MHz) transmitter
• Low-power, highly integrated radar components
• Data processing algorithms and data reduction techniques
• Hardware and/or software development for the ionospheric correction in space-borne radar sounders
• Data applications and post-processing techniques

Atmospheric Radar

• Low sidelobe, electronically steerable millimeter wave phased-array antennas and feed networks
• Low sidelobe, multi-frequency, multi-beam, shared aperture millimeter wave antennas
• Large (~300 wavelength), lightweight, low sidelobe, millimeter wave antenna reflectors and reflectarrays
• Lightweight deployable antenna structures and deployment mechanisms
• High power Ka-band and W-band transmitters (10 Kwatt)
• High-efficiency, low-cost, lightweight kA-band and W-band transmit/receive modules
• Advanced transmit/receive module concepts such as optically fed T/R modules
• On-board (real-time) pulse compression and image processing hardware and/or software
• Advanced data processing techniques for real-time rain cell tracking, and rapid 3-D rain mapping

Polarimetric Ocean/Land Scatterometer

• Shared aperture, multi-frequency antennas
• Large, lightweight, electronically steerable reflectarrays
• Dual-polarized antennas with high polarization isolation
• Lightweight deployable antenna structures and deployment mechanisms
• High efficiency, high power, phase stable L-band, C-band and Ku-band transmitters
• Low-power, highly integrated radar components
• Calibration techniques, data processing algorithms and data reduction techniques
• Data applications and post-processing techniques

Wide Swath Ocean and Surface Water Monitoring Altimeters

• Shared aperture, multi-frequency antennas
• Large, lightweight antenna reflectors and reflectarrays
• Lightweight deployable antenna structures and deployment mechanisms
• High efficiency, high power, phase stable C-band and Ku-band transmitters
• Real-time onboard radar data processing
• Calibration techniques, data processing algorithms and data reduction techniques
• Data applications and post-processing techniques

Geosynchronous Ocean Altimeter

• Core radar technologies and signal processing definition
  

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E1.06 Passive Infrared - Sub Millimeter
Lead Center: JPL
Participating Center(s): LaRC

Many NASA future Earth science remote sensing programs and missions require microwave- to submillimeter wavelength antennas, transmitters, and receivers operating in the 3-cm to 100-micron wavelength range (or a frequency range of 10 GHz to 3 THz). General requirements for these instruments include large-aperture (possibly deployable) antenna systems with rms surface accuracy of < 1/50th wavelength (or better); the ability to scan or image many beamwidths on the sky (array receivers); small low-power MMIC radiometers, and high-throughput, low power, backend correlators and spectrometers. The focus is on technology for passive radiometer systems that are more spectrally flexible, lighter, smaller, and use less power. These systems must be of durable design for use on aircraft platforms and at remote/autonomous observatory sites; they must also be suitable for space applications with lifetimes of 5 years or more. Earth remote sensing receivers typically operate at LN2 (or higher) temperatures and require moderate noise performance. Advances in cooler technology will enable use of technology presently used in astrophysics receivers, which are cooled to a few Kelvin for better sensitivity, requiring near quantum-noise-limited performance. For these systems, advancement is needed in primarily three areas: (1) the development of frequency-stabilized, broadband, tunable, fundamental local oscillator sources covering frequencies between 160 GHz and 3 THz; (2) the development of submillimeter-wave mixers in the 300-3000 GHz spectral region with improved sensitivity, stability, and IF bandwidth capability; and (3) the development of higher-frequency and higher-output-power MMIC circuits. Specific innovations are required in the following areas:

• Heterodyne system integration at the circuit and/or chip level is needed to extend monolithic microwave integrated circuit (MMIC) capability into the submillimeter regime. MMIC amplifier development for both power amplifiers and low noise amplifiers at frequencies up to several hundred GHz is solicited. Integration of a local oscillator multiplier chain, mixer, and intermediate frequency amplifier is one example. There is also a specific need to demonstrate radiometer systems using phased-arrays and MMIC radiometers from 60 GHz to approximately 400 GHz.
• Solid-state, phase-lockable local-oscillator sources with flight-qualifiable design approaches are needed with > 10 mw output power at 200 GHz and > 100 micro-watts at 1 THz; line widths should be < 100 kHz. Since heterodyne mixers are relatively broadband, a major limitation of existing local oscillator sources is a narrow tuning range, which requires many devices for the broad spectral coverage. For example, a single local-oscillator source that could tune from 1-2 THz with flat output power in excess of 10 micro-watts would find immediate use. These local oscillator sources should be compact and have direct current power requirements < 20 W.
• Stable local-oscillator sources are needed for heterodyne receiver system laboratory testing and development.
• Multi-channel spectrometers that analyze intermediate frequency signal bandwidths as large as 10 GHz with a frequency resolution of < 1 MHz that are small and lightweight and that use low direct current power (< 5 mw per channel) with high stability.
• Compact and reliable millimeter and submillimeter instrumentation that produces high sensitivity images simultaneously in multiple spectral bands.
• Schottky mixers with high sensitivity at T = 100K and above.
• Superconducting HEB mixers and SIS mixers.
• Receivers utilizing planar diodes or alternative reliable technologies in the 300-3000 GHz spectrum.
• Lightweight and compact radiometer calibration references covering 100-800 GHz frequency range.
• Lightweight, field portable, compact radiometer calibration references covering frequencies up to 200 GHz. The reference must be temperature stable to within 1 Kelvin with a minimum of 3 temperature settings between 250 and 350 Kelvin.
• Low cost, special purpose, ground based receivers to detect signals radiated from active satellites that are in orbit for estimating rain rate, water vapor, and cloud liquid water.
• Large diameter (up to 25-m) deployable antennas suitable for Earth remote sensing at frequencies up to 30 GHz.
• Calibrated radiometer systems that can achieve accuracy and stability of 0.1K.
  

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13.07 Thermal Control for Instruments
Lead Center: GSFC
Participating Center(s): None

Future instruments for NASA's Earth Science Enterprises will require increasingly sophisticated thermal control technology. Optical alignment and sensor needs are requiring ever tighter temperature control, heat flux levels from lasers and other similar devices are increasing, and cryogenic applications are becoming more common. Some applications may require significantly increased power levels while others may require extremely low heat loss for extended periods. The advent of very small instruments may also drive the need for new technologies, particularly since such small instruments will have low thermal capacitance. In general, high performance, versatility, low cost, smaller mass and volume (down to the MEMS level), and high reliability are the prime technology drivers. Furthermore, the drive towards 'off-the-shelf' commercial spacecraft buses presents engineering and technological challenges for instruments. Innovative proposals for instrument thermal control systems are sought in the following areas:

• Miniaturized (down to the MEMS level), cryogenic (3K - 80K) heat transport devices, especially those suitable for cooling sensors and very small electronics.
• Advanced, multi-evaporator, two-phase heat transport devices to isothermalize very large structures such as antennas and telescopes.
• Highly reliable, miniaturized Loop Heat Pipes and Capillary Pumped Loops which allow multiple heat load sources and multiple sinks.
• Advanced thermoelectric coolers capable of providing 100s of milliwatts of cooling at 150 K and below.
• Hybrid cooling systems that make optimal use of radiative coolers.
• Advanced analytical techniques for thermal modeling, focusing on techniques that can be easily integrated with emerging mechanical and optical analytical tools.
  

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