Four programs, i.e. TRMM, ADEOS2, ASTER, and ALOS are going on in Japanese Earth Observation programs. TRMM and ASTER are operating well, and TRMM operation will be continued to 2009. ADEOS2 was failed, but AMSR-E on Aqua is operating. ALOS (Advanced Land Observing Satellite) was successfully launched on 24^th Jan. 2006. ALOS carries three instruments, i.e., PRISM (Panchromatic Remote Sensing Instrument for Stereo Mapping), AVNIR-2 (Advanced Visible and Near Infrared Radiometer), and PALSAR (Phased Array L band Synthetic Aperture Radar). PRISM is a 3 line panchromatic push broom scanner with 2.5m IFOV. AVNIR-2 is a 4 channel multi spectral scanner with 10m IFOV. PALSAR is a full polarimetric active phased array SAR. PALSAR has many observation modes including full polarimetric mode and scan SAR mode. After the unfortunate accident of ADEOS2, JAXA still have plans of Earth observation programs. Next generation satellites will be launched in 2008-2012 timeframe. They are GOSAT (Greenhouse Gas Observation Satellite), GCOM-W and GCOM-C (ADEOS-2 follow on), and GPM (Global Precipitation Mission) core satellite. GOSAT will carry 2 instruments, i.e. a green house gas sensor and a cloud/aerosol imager. The main sensor is a Fourier transform spectrometer (FTS) and covers 0.76 to 15 μm region with 0.2 to 0.5 cm^-1 resolution. GPM is a joint project with NASA and will carry two instruments. JAXA will develop DPR (Dual frequency Precipitation Radar) which is a follow on of PR on TRMM. Another project is EarthCare. It is a joint project with ESA and JAXA is going to provide CPR (Cloud Profiling Radar). Discussions on future Earth Observation programs have been started including discussions on ALOS F/O.

This paper summarizes the initial PALSAR calibration and validation results, which were being carried out after the first activation of the PALSAR image on Feb. 15 2006. The PALSAR calibration and validation consists of the sensor characterization, SAR processor tuning, and image quality evaluation. During the three month initial calibration phase and two month initial calibration phase, sensor characterization through the raw data evaluation for most of the sensor modes were conducted for interpretation of the performance. In this paper, we focus on the results that were gained during first 7 months after the ALOS launch. Although three months remained by the ALOS operation start, the report may cover almost of the PALSAR CAL/VAL.

The Advanced Land Observing Satellite (ALOS) was successfully launched on January 24^th, 2006. This paper introduces the preliminary results of calibration and validation for two optical sensors of ALOS i.e., the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and the Advanced Visible and Near Infrared Radiometer type-2 (AVNIR-2). PRISM consists of three independent panchromatic radiometers, and is used to derive a digital surface model (DSM) with high spatial resolution, which is also an objective of the ALOS mission. So, the geometric calibration is important in generating a highly accurate DSM by stereo pair image of PRISM. The radiometric calibration is also important for AVNIR-2 as well as PRISM. The relative radiometric calibration is carrying out using acquired images over homogeneous targets such as ocean, deserts, ice and snow areas and the nighttime observation. The absolute radiometric calibration is applied the cross calibration method using calibrated satellite images i.e., MODIS onboard Terra/Aqua satellites, ASTER, SPOT-5 etc. In this paper, results of the first images acquisition and preliminary analysis for calibration and validation are described.

One of the series of satellite for the Global Change Observation Mission (GCOM) is the GCOM-W that will carry the Advanced Microwave Scanning Radiometer (AMSR) follow-on instrument. To keep the continuous observation by the current AMSR for the EOS (AMSR-E) on the Aqua satellite, an earliest launch date is desired. Current proposed launch year is 2010 in Japanese fiscal year. The AMSR-E instrument has been successfully operated for about 4-years and expected to continue providing measurements with high-spatial resolution and in C-band channels that are used to estimate all-weather sea surface temperature and land surface soil moisture. The total dataset period will be over 20-years if the AMSR-E observation can last until the GCOM-W launch. Among the GCOM mission objectives, GCOM-W will focus on the long-term observation of variations in water and energy circulation. In addition, further practical uses including numerical weather forecasting, maritime and meteorological monitoring, and ice applications will be promoted. The AMSR follow-on instrument will be a six-frequency, dual polarized passive microwave radiometer system to observe water-related geophysical parameters. It takes over the basic sensor concept of the AMSR-E instrument with some essential improvements on the calibration system and mitigation of radio-frequency interference (RFI) in C-band channels. Regarding the calibration system, some issues particularly for the warm load target will be investigated and improved based on the AMSR and AMSR-E experiences. Although mitigating the RFI problem is a difficult issue, some preliminary aircraft measurements of anthropogenic radio emissions have performed in Japan and used for assessing the possibilities of sub-band configuration in C-band. Prototyping the several critical components including the above has already started in the last Japanese fiscal year.

The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concluded that many collectiveobservations gave a aspect of a global warming and other changes in the climate system. It is very important to understand thisprocess accurately, and to construct the model by whom an environmental change is accurately forecast. Future earthobservation using satellite data should monitor global climate change, and should contribute to social benefits. Especially, human activities has given the big impacts to earth environment. This is a very complex affair, and nature itself also impacts the clouds,namely the seasonal variations. JAXA (former NASDA) has the plan of the Global Change Observation Mission (GCOM) formonitoring of global environmental change. SGLI (Second Generation GLI) onboard GCOM-C (Climate) satellite, which is one of this mission, is an optical sensor from Near-UV to TIR. SGLI can provide the various high accuracy products of aerosol, cloud information, various biophysical parameters (Biomass, Land Cover, Albedo, NPP, Water Stressed Vegetation, LST, etc.), coastal information (CDOM, SS, PAR, CHL, SST, etc.), and cryospheric information (Albedo, Snow/Ice Cover, NDII, Sea ice type, Snow Grain Size, NDSI, Snow Surface Temperature, etc.). This paper shows the introduction of the unique aspects and characteristics of the next generation satellite sensor, SGLI/GCOM-C, and shows the preliminary research for this sensor.

Recent developments in the fields of detectors on one hand and a significant change of national and international political and commercial constraints on the other hand led to a large number of proposals for spaceborne sensor systems focusing on Earth observation in the last months. Due to the commercial availability of TDI lines and fast readable CCD-Chips new sensor concepts are feasible for high resolution sensor systems regarding geometry and radiometry und their data products. Systemic approaches are essential for the design of complex sensor systems for dedicated tasks. Starting with system theory optically, mechanical and electrical components are designed and deployed. Single modules and the entire system have to be calibrated using suitable procedures. The paper gives an overview about current activities at German Aerospace Center on the field of innovative sensor systems for photogrammetry and remote sensing.

Millimeter and Sub-mm-wave imagers/sounders are considered for future meteorological geostationary satellite missions. A novel interferometric Geostationary Atmospheric Sounder (GAS) has been developed and a concept demonstrator is under construction. The concept is a response to the requirements of observations for nowcasting and short range forecasting in 2015-2025, as determined by EUMETSAT for post-MSG operational satellites observations. Prioritized parameters include vertical profiles of temperature and humidity with high temporal and horizontal resolution (15 min and 30 km) under all weather conditions. Frequency bands around 53GHz, 118GHz, 183GHz, 380GHz have the highest user priority and are all supported by GAS. The instrument relies on an innovative configuration of interferometer elements which enables the use of a sparse array and simplifies calibration.

A balloon-borne wide-band Fourier transform spectrometer named REFIR-PAD (Radiation Explorer in the Far InfraRed, Prototype for Applications and Development) has been developed at CNR-IFAC to perform the characterisation of the Earth's outgoing long-wave radiation in the far-infrared region. The spectroscopic characterisation of this region is expected to increase greatly our level of knowledge of the radiative effects of water content in the upper troposphere. The REFIR-PAD instrument provides spectrally-resolved nadir-sounding radiance measurements in the 100-1400 cm^-1 range, with a 0.5 cm^-1 resolution, covering the most part of the Earth's long-wave emission and including both the far-infrared and the better known middle-infrared region. REFIR-PAD was flown as a piggy-back payload on the CNES IASI-LPMAA stratospheric balloon gondola in June 2005 from Teresina, Brazil. The data collected in this mission, will provide valuable information for the development of a future space mission aimed to the operational monitoring of the upper troposphere water vapour and clouds in order to identify their climate signatures.

MARSCHALS is the airborne simulator of a proposed future satellite instrument to measure millimetre-wave limb emission from O₃, H₂O, CO and other trace gases in the upper troposphere and lower stratosphere. To achieve comparatively high vertical resolution and pointing stability, MARSCHALS scans the atmospheric limb in 1km vertical steps using a 235mm diameter antenna controlled by a dedicated inertial measurement unit. A quasi-optical network directs radiation from the antenna or an ambient (~300K) or cold (~90K) calibration target into three front-end receivers and suppresses each unwanted side-band by >30dB using multi-layer frequency selective surfaces. Each receiver comprises a waveguide mixer pumped subharmonically by a phase-locked LO and a wideband IF preamplifier. The IF outputs are directed to channeliser spectrometers of 200MHz resolution which instantaneously and contiguously cover 12GHz wide (RF) frequency bands centred near 300, 325 and 345GHz. To identify clouds, images of near-IR sunlight scattered into the limb direction are recorded concurrently by an 850nm wavelength camera. MARSCHALS has been built under ESA contract by a consortium led by Rutherford Appleton Laboratory in the UK, and had its first flights on the Russian Geophysica (M55) aircraft during 2005, culminating in a deployment during the SCOUT-O3 campaign based in Darwin, Australia. This paper describes the MARSCHALS instrument and an initial assessment of its performance, determined on ground and during flight.

The purpose of NASA's Science Mission Directorate's Earth Science Division (ESD) is to develop a scientific understanding of Earth's system and its response to natural or human-induced changes, and to improve prediction of climate, weather, and natural hazards. ESD conducts and sponsors research, collects new observations from space, develops technologies and extends science and technology education to learners of all ages. We work closely with our global partners in government, industry, and the public to enhance economic security, and environmental stewardship, benefiting society in many tangible ways. We conduct and sponsor research to answer fundamental science questions about the changes we see in climate, weather, and natural hazards, and deliver sound science that helps decision-makers make informed decisions. Using the view from space to study the Earth, researchers can better predict critical changes to Earth and its space environment. ESD has a critical role in implementing three major national directives: •Climate Change Research through the Climate Change Science Program •Global Earth Observation System of Systems through the Interagency Working Group on Earth Observations (IWGEO) •U.S Ocean Action Plan. NASA's ESD currently has a system of spacecraft collecting observations of the Earth system and in the months and years ahead will deploy new satellites and constellations with advanced measurement capabilities.

CloudSat is a NASA ESSP (Earth System Science Pathfinder Mission) that provides from a space the first global survey of cloud profiles and cloud physical properties, with seasonal and geographical variations. The data obtained will allow for clouds and cloud processes to be more accurately represented in global atmospheric models leading to improved climate change predictions, and eventually, weather forecasting. To achieve this ambitious goal, JPL (Jet Propulsion Laboratory) in collaboration with CSA (Canadian Space Agency) designed, developed, and tested a 94.05 GHz, W-band, microwave cloud profiling radar system derived from current ground-based and airborne systems. The CloudSat Project team is witnessing how well the instrument performs during in-flight operations with the recent successful launch. Although Level 1 (i.e. radiometric-corrected and geo-located) and Level 2 (i.e. retrieved geophysical parameters) science data products will not be released until the January 2007 timeframe, the yet uncalibrated and unvalidated "quick look" products, available to the general public on the CloudSat Data Processing Center website, provide every indication that the mission objectives will be met.

OSTM (Ocean Surface Topography Mission) will provide continuity of ocean topography measurements that began with TOPEX/Poseidon and are currently being carried out by Jason. Measurements made by the three missions will allow scientists to better understand ocean circulation, climate change processes, and sea level rise on a multi-decadal scale. While CNES (Centre National d'Etudes Spatiales) will provide the primary satellite instrument, a nadir-pointed altimeter, and a precision orbit determination system, NASA (National Aeronautics and Space Administration) will provide an instrument suite to provide the necessary measurement accuracy. The AMR (Advanced Microwave Radiometer) will measure atmospheric water vapor content to determine how it affects the accuracy of the altimeter readings. The GPSP (Global Positioning System Payload) will be used to accurately pinpoint the position of the satellite above the ocean surface. Finally, there is the LRA (Laser Retroreflector Array), a passive, supporting instrument that will allow ground-based laser ranging stations to also pinpoint the position of the satellite. Both the GPSP and LRA will be used to enhance the precision orbit determination system performance. The instruments are now undergoing ground test. In conjunction with in-flight calibration and validation activities these efforts will help to ensure mission success.

The NASA Orbiting Carbon Observatory (OCO) will make space-based measurements of atmospheric CO₂ with the precision, resolution, and coverage needed to characterize CO₂ sources and sinks on regional scales and quantify their variability over the seasonal cycle. This Earth System Science Pathfinder (ESSP) mission will be launched in late 2008 and will fly in a 705 km altitude, 1:26 PM sun-synchronous polar orbit that provides near-global coverage of the sunlit hemisphere with a 16-day ground track repeat cycle. OCO carries a single instrument that incorporates 3 high resolution grating spectrometers that will make boresighted measurements of reflected sunlight in near-infrared CO₂ and molecular oxygen (O₂) bands. These measurements will be combined to provide spatially resolved estimates of the column-averaged CO₂ dry air mole fraction, XCO₂. The instrument collects 12 to 24 X_CO2 soundings/second over the sunlit portion of the orbit, yielding 200 to 400 soundings per degree of latitude, or 7 to 14 million soundings every 16 days. Thick clouds and aerosols will reduce the number of soundings available for X_CO2 retrievals by 80-90%, but the remaining data is expected to yield XCO₂ estimates with accuracies of ~0.3 to 0.5% (1 to 2 ppm) on regional scales every month.

Aquarius/SAC-D is a cooperative international mission developed between the National Aeronautics and Space Administration (NASA) of United States of America (USA) and the Comisión Nacional de Actividades Espaciales (CONAE) of Argentina. The overall mission objective is to contribute to the understanding of the total Earth system and the consequences of the natural and man-made changes in the environment of the planet. Major themes are: ocean surface salinity, carbon, water cycle, geo-hazards, and cryosphere.

We propose to apply the technique of synthetic aperture radar interferometry to the measurement of ocean surface topography at spatial resolution approaching 1 km. The measurement will have wide ranging applications in oceanography, hydrology, and marine geophysics. The oceanographic and related societal applications are briefly discussed in the paper. To meet the requirements for oceanographic applications, the instrument must be flown in an orbit with proper sampling of ocean tides.

The Geostationary Synthetic Thinned Aperture Radiometer, GeoSTAR, is a new concept for a microwave atmospheric sounder intended for geostationary satellites such as the GOES weather satellites operated by NOAA. A small but fully functional prototype has recently been developed at the Jet Propulsion Laboratory to demonstrate the feasibility of using aperture synthesis in lieu of the large solid parabolic dish antenna that is required with the conventional approach. Spatial resolution requirements dictate such a large aperture in GEO that the conventional approach has not been feasible, and it is only now, with the GeoSTAR approach, that a GEO microwave sounder can be contemplated. Others have proposed GEO microwave radiometers that would operate at sub-millimeter wavelengths to circumvent the large-aperture problem, but GeoSTAR is the only viable approach that can provide full sounding capabilities equal to or exceeding those of the AMSU systems now operating on LEO weather satellites and which have had tremendous impact on numerical weather forecasting. GeoSTAR will satisfy a number of important measurement objectives, many of them identified by NOAA as unmet needs in their GOES-R pre-planned product improvements (P3I) lists and others by NASA in their research roadmaps and as discussed in a white paper submitted to the NRC Decadal Survey. The performance of the prototype has been outstanding, and this proof of concept represents a major breakthrough in remote sensing capabilities. The GeoSTAR concept is now at a stage of development where an infusion into space systems can be initiated, either on a NASA sponsored research mission or on a NOAA sponsored operational mission. GeoSTAR is an ideal candidate for a joint "research to operations" mission, and that may be the most likely scenario. Additional GeoSTAR related technology development and other risk reduction activities are under way, and a GeoSTAR mission is feasible in the GOES-R/S time frame, 2012-2014.

Understanding the Earth's climate and how it responds to climate perturbations relies on knowledge of how atmospheric moisture, clouds, latent heating, and the large-scale circulation vary with changing climate conditions. The physical process that links these key climate elements is precipitation. The Global Precipitation Measurement (GPM) mission will be key to answering the following related research questions: •how are global precipitation, evaporation, and the cycling of water changing? •how are variations in local weather, precipitation, and water resources related to global climate variation? •how can weather forecast duration and reliability be improved by new space-based observations, data assimilation and modeling? GPM is a joint initiative with the Japan Aerospace Exploration Agency (JAXA) and other international partners that integrates previously planned and dedicated missions in a scalable and evolving constellation of multiple spacecraft and data processing and validation ground systems. Its science objectives are: •to improve ongoing efforts to predict climate by providing near-global measurement of precipitation, its distribution, and physical processes; •to improve the accuracy of weather and precipitation forecasts through more accurate measurement of rain rates and latent heating; •to provide more frequent and complete sampling of the Earth's precipitation. It is a potential component of the Global Earth Observation System of Systems (GEOSS) as envisioned by the intergovernmental Group on Earth Observations (GEO). GPM will consist of a core spacecraft to measure precipitation structure and to provide a calibration standard for the constellation spacecraft, an international constellation of NASA and contributed spacecraft to provide frequent precipitation measurements on a global basis, calibration/validation sites distributed globally with a broad array of precipitation-measuring instrumentation, and a global precipitation data system to produce and distribute global rain maps and climate research products. GPM is now in formulation phase. GPM launches are targeted to begin in 2013.

It is essential to measure global precipitation not only for the research of the climate change but also for the water resources management. In order to satisfy the requirements, the Global Precipitation Measurement (GPM) mission was proposed jointly by US and Japan. The basic concept of the GPM is to provide three hourly global precipitation maps using eight constellation satellites equipped with microwave radiometers and a core satellite equipped with the Dual-frequency Precipitation Radar (DPR) and a microwave radiometer. The DPR that uses radio waves of 14 and 35 GHz is now being developed in Japan. The DPR will observe three-dimensional precipitation structure and will provide essential data for microwave rain retrieval. GPM is partly a follow-on mission of the Tropical Rainfall Measuring Mission (TRMM), but the GPM will extend the observation to cold regions where solid precipitation frequently exists. Rain retrieval algorithms that use the DPR data are also being developed. Using two wavelength data, two parameters in the raindrop size distribution could be retrieved, which would result in precise rain retrieval. The retrieval of solid precipitation rate is another challenge. Several algorithms including a combination with the microwave radiometer would be applied to the DPR. It is important for the DPR algorithm validation to compare between precipitation rate through the calculation of DPR algorithm and that of the directly observed precipitation rate over the validation site. For this purpose, the most important and difficult issue is to construct the database of the physical parameters for the precipitation retrieval algorithms of DPR from the ground-based data using well-calibrated instruments.

The Global Precipitation Measurement (GPM) Microwave Imager (GMI) instrument is a multi-channel, conicalscanning, microwave radiometer serving an essential role in the near-global-coverage and frequent-revisit-time requirements of GPM. As a part of its contribution to GPM, NASA will provide a GMI instrument and a spacecraft for the Core observatory and is considering the acquisition of a second GMI instrument for placement aboard a constellation spacecraft with a payload and orbit to be defined. In March 2005, NASA chose Ball Aerospace & Technology Corporation to provide the GMI instrument(s). This paper describes the GMI instrument, the technical performance requirements, its role within the combined passive and active microwave measurements on the Core observatory, and the timeline for GMI development and acquisition.

The Global Precipitation Measurement (GPM) Mission is a collaboration between the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA), and other US and international partners, with the goal of monitoring the diurnal and seasonal variations in precipitation over the surface of the earth. These measurements will be used to improve current climate models and weather forecasting, and enable improved storm and flood warnings. This paper gives an overview of the mission architecture and addresses the status of some key trade studies, including the geolocation budgeting, design considerations for spacecraft charging, and design issues related to the mitigation of orbital debris.

MODIS is currently onboard NASA's EOS Terra and Aqua spacecraft launched in December 1999 and May 2002, respectively. Together, Terra and Aqua MODIS have generated over 10 years of global observations for the study of changes in the Earth's land, oceans, and atmosphere. Each sensor produces more than 40 science data products using measurements from 36 spectral bands with wavelengths ranging from 0.41 to 14.4μm. MODIS on-orbit radiometric calibration is performed using a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) for the reflective solar bands (RSB) and a blackbody (BB) for the thermal emissive bands (TEB). In addition, regularly scheduled lunar observations are used to track RSB radiometric calibration stability. This paper discusses Aqua MODIS radiometric calibration performance using four-years of on-orbit calibration data. Results include detector noise characterization (SNR for the RSB and NEdT for the TEB), short- and long-term radiometric stability, and optics (scan mirror and solar diffuser) degradation.

The Moderate Resolution Imaging Spectroradiometer (MODIS) flight model 1 (FM-1) was launched on-board NASA's EOS Aqua spacecraft on May 04, 2002. MODIS has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μm and 16 thermal emissive bands (TEB) with wavelengths from 3.7 to 14.4μm. Typical sensor spectral characterization includes measurements of in-band (IB) and out-of-band (OOB) relative spectral responses (RSR) or spectral response functions (SRF), center wavelengths (CW) and bandwidths (BW). During MODIS instrument pre-launch calibration and characterization, these parameters were measured using a spectral measurement assembly (SpMA) by the instrument vendor. In addition to its on-orbit radiometric calibration capability, MODIS has a unique on-board calibrator, spectro-radiometric calibration assembly (SRCA) that can be used to monitor RSB on-orbit spectral performance. This paper presents an overview of MODIS spectral characterization methodologies, from pre-launch to on-orbit. It describes Aqua MODIS SRCA operational activities in spectral mode, summarizes the results from its four-years of on-orbit spectral measurements, and discusses lessons learned for future sensor design and development. The results show that on-orbit changes of Aqua MODIS RSB center wavelengths and bandwidths have been very small, typically less than 0.5nm for the CW and less than 1nm for the BW.

NASA's EOS Aqua spacecraft was launched on May 04, 2002. The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of the six Earth-observing sensors aboard the EOS Aqua spacecraft. MODIS is the highest spatial resolution instrument on the Aqua platform with data products generated in 250m, 500m, and 1000m resolutions (nadir). It has 36 spectral bands, a total of 490 detectors, located on four focal plane assemblies (FPAs) with two of them controlled during operation at 83K by a passive radiative cooler. In addition to radiometric calibration and spectral characterization, MODIS spatial performance was extensively characterized pre-launch, including measurements of band-to-band registration (BBR), FPA to FPA registration (FFR), line spread function (LSF), modulation transfer function (MTF), and instantaneous field-of-view (IFOV). The sensor's spatial characterization is monitored by an on-board calibrator, the spectro-radiometric calibration assembly (SRCA). In this paper, we will briefly describe MODIS SRCA spatial characterization methodologies and operational activities. We will focus on the sensor's spatial performance using four years of on-orbit observations and, consequently, evaluate the SRCA's performance. On-orbit results of key spatial characterization parameters (BBR, FFR, and MTF) will be examined and compared to pre-launch measurements and design requirements.

The Advanced Land Imager (ALI) was developed as a prototype sensor for follow on missions to Landsat-7. It was launched in November 2000 on the Earth Observing One (EO-1) satellite as a nominal one-year technology demonstration mission. As of this writing, the sensor has continued to operate in excess of 5 years. Six of the ALI's nine multi-spectral (MS) bands and the panchromatic band have similar spectral coverage as those on the Landsat-7 ETM+. In addition to on-board lamps, which have been significantly more stable than the lamps on ETM+, the ALI has a solar diffuser and has imaged the moon monthly since launch. This combined calibration dataset allows understanding of the radiometric stability of the ALI system, its calibrators and some differentiation of the sources of the changes with time. The solar dataset is limited as the mechanism controlling the aperture to the solar diffuser failed approximately 18 months after launch. Results over 5 years indicate that: the shortest wavelength band (443 nm) has degraded in response about 2%; the 482 nm and 565 nm bands decreased in response about 1%; the 660 nm, 790 nm and 868 nm bands each degraded about 5%; the 1250 nm and 1650 nm bands did not change significantly and the 2215 nm band increased in response about 2%.

The U.S. radiometric calibration procedure for the reflective bands of the Landsat-5 Thematic Mapper was updated in May 2003. This update was based on a model of the performance of the instrument developed from its response to the best-behaved internal calibration lamp and from a cross calibration with Landsat-7 ETM+ that occurred in June 1999. Since this update was performed, there have been continued attempts to validate the model. These validations have relied primarily upon data acquired over deserts of the world. These studies have been limited by the amount of data available over any one site for the 22-year life of the mission. Initial attempts over the desert Southwest of the United States were inconclusive, though they were suggestive of additional degradation occurring in the shorter wavelength channels. More recently, significant holdings from European Space Agency of data over North Africa have been made available for analysis. The North Africa test area results to date for one site in Libya are considerably less noisy than the North American datasets. They indicate an exponential-like decay of about 19%, 16%, 8% and 4% for TM bands 1, 2, 3 and 4, with the degradation, at least in bands 1 and 2 occurring throughout the mission. The current model shows changes of roughly the same magnitude, but with the change occurring more rapidly so that nearly all the change is completed in 4 years. These results are generally consistent with independent work going on outside of this effort. Additional sites are being analyzed as data become available.

The ASTER is a high-resolution optical sensor for observing the Earth on the Terra satellite launched in 1999. The ASTER consists of three radiometers, the VNIR in the visible and near-infrared region, the SWIR in the shortwave infrared region, and the TIR in the thermal infrared region. The on-board calibration devices of the VNIR and the SWIR were two halogen lamps and photodiode monitors. In orbit three bands of the VNIR showed a rapid decrease in the output signal while all SWIR bands remained stable. The TIR has one on-board blackbody and is unable to see the dark space. Therefore the temperature of the on-board blackbody of the TIR remains at 270 K in the short-term calibration for the offset calibration, and is varied from 270 K to 340 K in the long term calibration for the offset and gain calibration. The long term calibration showed a decrease of the TIR response in orbit. The radiometric calibration coefficients of the VNIR and the TIR were fit to smooth functions.

It is estimated that in order to best detect real changes in the Earth's climate system, space based instrumentation measuring the Earth Radiation Budget (ERB) needs to remain calibrated with a stability of 0.3% per decade. This stability is beyond the specification of existing ERB programs such as the Clouds and the Earth's Radiant Energy System (CERES, using three broadband radiometric scanning channels: the shortwave 0.3 - 5μm, total 0.3- > 100μm, and window 8 - 12μm). It is known that when in low earth orbit, optical response to blue/UV radiance can be reduced significantly due to UV hardened contaminants deposited on the surface of the optics. Typical onboard calibration lamps do not emit sufficient energy in the blue/UV region, hence this darkening is not directly measurable using standard internal calibration techniques. This paper details a study using a model of contaminant deposition and darkening, in conjunction with in-flight vicarious calibration techniques, to derive the spectral shape of darkening to which a broadband instrument is subjected. The model ultimately uses the reflectivity of Deep Convective Clouds as a stability metric. The results of the model when applied to the CERES instruments on board the EOS Terra satellite are shown. Given comprehensive validation of the model, these results will allow the CERES spectral responses to be updated accordingly prior to any forthcoming data release in an attempt to reach the optimum stability target that the climate community requires.

The paper presents the current status of the operational calibration facility that can be used for radiometric, spectral and geometric on-ground characterisation and calibration of imaging spectrometers. The European Space Agency (ESA) co-funded this establishment at DLR Oberpfaffenhofen within the framework of the hyper-spectral imaging spectrometer Airborne Prism Experiment (APEX). It was designed to fulfil the requirements for calibration of APEX, but can also be used for other imaging spectrometers. A description of the hardware set-up of the optical bench will be given. Signals from two sides can alternatively be sent to the hyper-spectral sensor under investigation. Frome one side the spatial calibration will be done by using an off-axis collimator and six slits of different width and orientation to measure the line spread function (LSF) in flight direction as well as across flight direction. From the other side the spectral calibration will be performed. A monochromator provides radiation in a range from 380 nm to 13 μm with a bandwidth between 0.1 nm in the visible and 5 nm in the thermal infrared. For the relative radiometric calibration a large integrating sphere of 1.65 m diameter and exit port size of 55 cm × 40 cm is used. The absolute radiometric calibration will be done using a small integrating sphere with 50 cm diameter that is regularly calibrated according to national standards. This paper describes the hardware components and their accuracy, and it presents the software interface for automation of the measurements.

This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibration. Knowledge of the behavior of the diffuser is therefore most important. From measurements of launched instruments in-orbit it has been discovered that when a diffuser is used in the vacuum of space the BSDF (Bi-directional Scattering Distribution Function) can change with respect to the one in ambient conditions. This is called the air/vacuum effect and has been simulated in this study by measuring the BSDF in a laboratory in ambient as well as vacuum conditions, results of this part of the study will be reported. Another effect on the BSDF is not related to the air/vacuum effect, but to the design parameters of the optical system and the scattering properties of the diffuser. The effect is called Spectral Features and is a noise like structure superimposed on the BSDF. To observe this effect, spectral and spatial (partially) coherence light is needed. High-resolution spectrometers provide the spectral coherence and a narrow field of view provides the spatial coherence. Modern space spectrometers have high spectral resolution and/or a small field of view (high spatial resolution). Different diffusers create different speckle patterns leading to different Spectral Features amplitudes. Therefore the choice of diffuser can be very critical with respect to the required absolute radiometric calibration of an instrument. Even if the Spectral Features are small it can influence the error budget of the retrieval algorithms for the level 2 products. In this presentation diffuser trade-off results are presented and the Spectral Features model applied to the optical configuration of the MERIS instrument is compared to in-flight measurements of MERIS. The introduction describes the use of diffusers in earth-observation satellites and why they cause spectral features. In Sec.2 the physical background of the spectral features, speckles, is discussed. Section 3 shows the results from air/vacuum effect measurements (SubSec.3.1), spectral features amplitude measurements on our in-house setup and simulations in a single graphical display (SubSec.3.2 ), and the measured and simulated results for the MERIS instrument (SubSec.3.3). The following sections deal with a description of the measuring setup and the model that has been made to do the simulations. Finally, in the discussion, topics like what is the best diffuser and what can be done to minimize the amplitude of the spectral features will be dealt with.

Geostationary Ocean Color Imager (GOCI) is under development to provide a monitoring of ocean-color around the Korean Peninsula from geostationary platforms. It is planned to be loaded on Communication, Ocean, and Meteorological Satellite (COMS) of Korea. In this paper main mission of GOCI and corresponding major technical requirements are introduced. Also characteristic of the GOCI radiometric model for calibration is introduced. The GOCI is modeled as a nonlinear system in order to reflect a nonlinear characteristic of detector. Radiometric calibration concept is explained through radiometric parameter estimation method and offset correction method. For the GOCI, the offset signal depends on each spectral channel because dark current offset signal is a function of integration time which is different from channel to channel. The offset parameter estimation method using offset signal measurements for two integration time setting is described. Also error propagation for radiance estimation is examined in this paper. The error propagation for nonlinear GOCI instrument will be slightly larger than a linear instrument. The increase of error propagation induced by the nonlinear parameter depends on the integration time and the input radiance.

Remote sensing data acquired by satellite or airborne sensor need on ground validation measurements. As concern volcanoes monitoring, important information may be retrieved by observing these targets in the InfraRed spectral range. A portable μFTIR (Fourier Transform Infrared Interferometer) capable of making sensitive and accurate measurements of radiance and emissivity of surface in the (600-5000 cm^-1) spectral range with a spectral resolution of 2 cm^-1 is available at the remote sensing laboratory of INGV (Rome). These kinds of measurements are very important firstly for the validation of remote sensed data and secondly for the improvement of many gas models used in volcanology for the diagnosis of volcano inner state. On 2003 μFTIR in situ spectral emissivity measurements were made during field surveys on selected test sites on Mount Etna. This area was observed also by a Fourier interferometer (MIROR) on board on a Dornier 228 and by ASTER a satellite borne sensor. The MIROR and ASTER data have been calibrated and compared with ground measurements. The agreement suggested to organize periodic measurements on selected test sites of Italian volcanic regions e.g. Solfatara and Stromboli volcano.

CMOS APS technology allows including signal processing in the sensor array. Inclusion of functionality however will come at a cost both financially and in the field of limited applicability. Based on two real world examples (micro digital sunsensor core and lightning flash detector for Meteosat Third Generation (MTG)) it will be demonstrated that large system gains can be obtained by devising smart focal planes. Therefore it is felt that the advantages outweigh the disadvantages for some applications, making it worth to spend the effort on system integration.

We have exploited the artificial atom-like properties of epitaxially grown self-assembled quantum dots (QDs) for the development of high operating temperature long wavelength infrared (LWIR) focal plane arrays (FPAs). QD infrared photodetectors (QDIPs) are expected to outperform quantum well infrared detectors (QWIPs) and are expected to offer significant advantages over II-VI material based FPAs. We have used molecular beam epitaxy (MBE) technology to grow multi-layer LWIR Dot-in-a-Well (DWELL) structures based on the InAs/InGaAs/GaAs material system. This hybrid quantum dot/quantum well device offers additional control in wavelength tuning via control of dot-size and/or quantum well sizes. DWELL QDIPs were also experimentally shown to absorb both 45o and normally incident light. Thus we have employed a reflection grating structure to further enhance the quantum efficiency. The most recent devices exhibit peak responsivity out to 8.1 microns. Peak detectivity of the 8.1 μm devices has reached ~ 1 x 1010 Jones at 77 K. Furthermore, we have fabricated the first long-wavelength 640x512 pixels QDIP imaging FPA. This QDIP FPA has produced excellent infrared imagery with noise equivalent temperature difference of 40 mK at 60K operating temperature.

Standard GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIP) are considered as a technological choice for 3^rdgeneration thermal imagers [1], [2]. Since 2001, the THALES Group has been manufacturing sensitive arrays using AsGa based QWIP technology at THALES Research and Technology Laboratory. This QWIP technology allows the realization of large staring arrays for Thermal Imagers (TI) working in the Infrared region of the spectrum. The main advantage of this GaAs detector technology is that it is also used for other commercial devices. The GaAs industry has lead to important improvements over the last ten years and it reaches now an undeniable level of maturity. As a result the key parameters to reach high production yield: large substrate and good uniformity characteristics, have already been achieved. Considering defective pixels, the main usual features are a high operability (> 99.9%) and a low number of clusters having a maximum of 4 dead pixels. Another advantage of this III-V technology is the versatility of the design and processing phases. It allows customizing both the quantum structure and the pixel architecture in order to fulfill the requirements of any specific applications. The spectral response of QWIPs is intrinsically resonant but the quantum structure can be designed for a given detection wavelength window ranging from MWIR, LWIR to VLWIR.

The HgCdTe infrared detector technology developed by CEA-LETI and industrialized by Sofradir is mature and reproducible, and the n on p planar ion implanted diode junction formation, which is well mastered for lot of years, allows high yields to be achieved in production. Even if most of the devices produced today are FPAs with increasing complexities (megapixel) operating in MWIR bands, HgCdTe FPAs with longer and longer cut off wavelengths become more and more available. Arrays of 384x288 with a pitch of 25μm are already available in production at Sofradir for LWIR bands (9-10μm & 11μm and operating temperature 77-85K & 70K respectively). Improvement of both the material (with state of the art CdZnTe lattice matched substrates, state of the art HgCdTe epitaxial layers grown by liquid phase (LPE)), and of the photovoltaic detector process (improved dark current technology), have allowed FPAs with longer cut off wavelengths (VLWIR) to be fabricated. These VLWIR (cut-off wavelengths in the 12-18μm range) dedicated to spectroscopy or broadband low flux applications operate at low temperatures around 50K and exhibit a very low dark current compatible with low flux applications. In this paper we present the latest developments of VLWIR FPAs of TV/4 typical size (320x256, 30μm pitch, 18 μm cut-off) made in Defir (LETI-Sofradir joint laboratory).

Remote sensing from space is an emerging market for applications in security, climate research, weather forecast, and global environmental monitoring, to mention a few. In particular, next generation systems demand for large, two-dimensional arrays in the short (SWIR, 0.9-2.5 μm) and the very long wavelength infrared (VLWIR) spectral range up to 15 μm. AIM's developments for space applications benefit from AIM's experiences in high-performance thermal imaging and seeker-head applications. AIM has delivered a 13 μm cut-off demonstrator for a high resolution Fourier-transform imaging spectrometer in limb geometry. For this 256 x 256 VLWIR sensor we measured a responsivity of 100 LSB/K and a noise equivalent temperature difference of 22 mK with 14 bit ADCs at 880 Hz full frame-rate. The substrate and epitaxial layer grown at AIM exhibit very good uniformity and low dark currents. Currently, AIM develops a 1024 x 256 SWIR detector (0.9-2.5 μm) with a capacitance transimpedance amplifier (CTIA) for hyperspectral imaging. The radiation hardness of AIM's FPA technology (MCT sensor and Silicon read-out integrated circuit) has been successfully tested by a total ionization dose (TID) experiment using ESTEC's ⁶⁰Co γ-source. Our reference module withstands 30 krad TID. For enhanced reliability of the IDCA, AIM has developed a compact 1 W pulse-tube cooler with flexure bearing compressor, which induces also a very low vibration output. In summary, AIM will be able to supply space qualified detector modules covering the spectral range from 0.9 to 13 μm in the near future.

The GAIA mission of the European Space Agency (ESA) comprises two Astro telescopes with a very large common focal plane. The focal plane assembly consist of about 180 CCDs and accompanying video chains. The CCDs are operating in a TDI mode with complex windowing- and binning modes. Low noise, large dynamic range, linearity are mandatory for success of the Mission. Therefore, ESA has initiated a technology demonstrator, which should demonstrate the technical feasibility. Astrium-SAS in Toulouse and DLR-IPF in Berlin have successfully performed the study, in which DLR has developed the CCD- video electronics and the Interconnection Modules for the Focal Plane Demonstrator. The requirements, the conceptional design and the results are presented in this paper.

Sofradir started to work in the field of space applications and especially in the earth observation domain in the beginning of the 1990^th. Thanks to the work done with the support of the French Ministry of Defense and the European Space Agency, Sofradir has acquired a large know-how and became a major supplier for European space industry. Nowadays, Sofradir technologies offer possibilities to develop a large panel of high reliable detectors like long linear arrays or two dimensional arrays covering bandwidth from visible to 15 μm based on qualified Mercury Cadmium Telluride (MCT) technology. In a near future, latest technology developments will enable to offer new detectors features in order to simplify instruments designs. In particular, these latest developments concern dual band detectors, increase in format, pitch reduction and implementation of new functions on the FPA like analogue to digital converter. This paper proposes an overview of Sofradir technology capabilities for design of custom space detectors. In particular this paper presents latest technology developments with new results in visible, long wavelength and dual band technology capabilities. Then, the different approaches for future space FPA are discussed based on examples of manufacturing.

A 5m GSD satellite camera with 12 narrow spectral bands in the VNIR region is being developed by El-Op, Israel, for a cooperative project between CNES (France) and the Israel Space Agency. The satellite, called "VENμS" (Vegetation and Environment monitoring on a New Micro-Satellite) will enable evaluation of the use of high-resolution, high repetitivity, super-spectral imaging data for vegetation and environmental monitoring. The camera will image a limited number of selected sites around the globe with a two-day revisit interval. Highly demanding requirements for signal-to-noise ratio, radiometric accuracy, band-to-band registration and precise location on the ground will ensure the validity of the data. It will also help to define the optimal set of bands and the image processing algorithms of future instruments in the framework of the GMES program. The satellite bus will be built by Israel Aircraft Industries and will also carry an experimental ion propulsion system developed by Rafael (Israel).

Three dimensional imaging of planetary and lunar surfaces has traditionally been the purview of Synthetic Aperture Radar payloads. We propose an active imaging technique that utilizes laser frequency diversity coupled with spatial heterodyne imaging. Spatial heterodyne imaging makes use of a local oscillator which encodes pupil plane object information on a carrier frequency. The object information is extracted via Fourier analysis. Snapshots of the encoded pupil plane information are acquired as the frequency of the illumination laser is varied in small steps (GHz). The resulting three-dimensional data cube is processed to provide angle-angle-range information. The range resolution can be adjusted from microns to meters simply by adjusting the range over which the illuminator laser frequency is varied. The proposed technique can provide fine resolution contour maps of planetary surfaces having widely varying characteristics of importance to science exploration, such as the search for astrobiological habitat niches near the surface of heavily irradiated Europa. This information can be used to better understand the geological processes that form the surface features, and help characterize candidate potential habitat sites on the surface of Europa and other planetary bodies of interest. In this paper we present simulations and experimental data that demonstrate the concept.

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service is planned to be launched onto Geostationary Earth Orbit in 2008. The meteorological payload of COMS is an imager which will monitor meteorological phenomenon around the Korean peninsular intensively and of Asian-side full Earth disk periodically. The meteorological imager (MI) of COMS has 5 spectral channels, 1 visible channel with the resolution of 1 km at nadir and 4 infrared channels with the resolution of 4 km at nadir. The characteristics of the COMS MI are introduced in the view points of user requirements, hardware features, and operation characteristics.

This paper assesses the effectiveness of a signal-to-noise ratio (SNR) enhancement technology for hyperspectral imagery to examine whether it can better serve remote sensing applications. A hyperspectral data set acquired using an airborne Short-wave-infrared Full Spectrum Image II with man-made targets in the scene of the data set was tested. Spectral angle mapper and end-members of different target materials were used to measure the superficies of the targets and to assess the detectability of the targets before and after applying the SNR enhancement technology to the data set. The experimental results show that small targets, which cannot be detected in the original data set due to inadequate SNR and low spatial resolution, can be detected after the SNR of the data set is enhanced.

This paper describes the experiment of the repeat pass interferometric SAR using Pi-SAR(L). The air-borne repeat-pass interferometric SAR is expected as an effective method to detect landslide or predict a volcano eruption. To obtain a high-quality interferometric image, it is necessary to make two flights on the same flight pass. In addition, since the antenna of the Pi-SAR(L) is secured to the aircraft, it is necessary to fly at the same drift angle to keep the observation direction same. We built a flight control system using an auto pilot which has been installed in the airplane. This navigation system measures position and altitude precisely with using a differential GPS, and the PC Navigator outputs a difference from the desired course to the auto pilot. Since the air density is thinner and the speed is higher than the landing situation, the gain of the control system is required to be adjusted during the repeat pass flight. The observation direction could be controlled to some extent by adjusting a drift angle with using a flight speed control. The repeat-pass flight was conducted in Japan for three days in late November. The flight was stable and the deviation was within a few meters for both horizontal and vertical direction even in the gusty condition. The SAR data were processed in time domain based on range Doppler algorism to make the complete motion compensation. Thus, the interferometric image processed after precise phase compensation is shown.

Previous successful international cooperative efforts offer a wealth of experience in dealing with highly sensitive issues, but cooperative remote sensing for monitoring and understanding the global environmental is in the national interest of all countries. Cooperation between international partners is paramount, particularly with the Russian Federation, due to its technological maturity and strategic political and geographical position in the world. Based on experience gained over a decade of collaborative space research efforts, continued cooperation provides an achievable goal as well as understanding the fabric of our coexistence. Past cooperative space research efforts demonstrate the ability of the US and Russian Federation to develop a framework for cooperation, working together on a complex, state-of-the-art joint satellite program. These efforts consisted of teams of scientists and engineers who overcame numerous cultural, linguistic, engineering approaches and different political environments. Among these major achievements are: (1) field measurement activities with US satellites MSTI and MSX and the Russian RESURS-1 satellite, as well as the joint experimental use of the US FISTA aircraft; (2) successful joint Science, Conceptual and Preliminary Design Reviews; (3) joint publications of scientific research technical papers, (4) Russian investment in development, demonstration and operation of the Monitor-E spacecraft (Yacht satellite bus), (5) successful demonstration of the conversion of the SS-19 into a satellite launch system, and (6) negotiation of contractual and technical assistant agreements. This paper discusses a new generation of science and space capabilities available to the Remote Sensing community. Specific topics include: joint requirements definition process and work allocation for hardware and responsibility for software development; the function, description and status of Russian contributions in providing space component prototypes and test articles; summary of planned experimental measurements and simulations; results of the ROKOT launch system; performance of the Monitor-E spacecraft; prototype joint mission operations control center; and a Handbook for Success in satellite collaborative efforts based upon a decade of lessons learned.

This paper discusses the concept and design of a real-time Digital Beamforming Synthetic Aperture Radar (DBSAR) for airborne applications which can achieve fine spatial resolutions and wide swaths. The development of the DBSAR enhances important scientific measurements in Earth science, and serves as a prove-of-concept for planetary exploration missions. A unique aspect of DBSAR is that it achieves fine resolutions over large swaths by synthesizing multiple cross-track beams simultaneously using digital beamforming techniques. Each beam is processed using SAR algorithms to obtain the fine ground resolution without compromising fine range and azimuth resolutions. The processor uses an FPGA-based architecture to implement digital in-phase and quadrature (I/Q) demodulation, beamforming, and range and azimuth compression. The DBSAR concept will be implemented using the airborne L-Band Imaging Scatterometer (LIS) on board the NASA P3 aircraft. The system will achieve ground resolutions of less than 30 m and swaths of 10 km from an altitude of 8 km.

The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is a comprehensive suite of active and passive sensors including a 20Hz 230mj Nd:YAG lidar, a visible wavelength Earth-looking camera and an imaging infrared radiometer. CALIPSO flies in formation with the Earth Observing System Post-Meridian (EOS PM) train, provides continuous, near-simultaneous measurements and is a planned 3 year mission. CALIPSO was launched into a 98 degree sun synchronous Earth orbit in April of 2006 to study clouds and aerosols and acquires over 5 gigabytes of data every 24 hours. Figure 1 shows the ground track of one CALIPSO orbit as well as high and low intensity South Atlantic Anomaly outlines. CALIPSO passes through the SAA several times each day. Spaced based remote sensing systems that include multiple instruments and/or instruments such as lidar generate large volumes of data and require robust real-time hardware and software mechanisms and high throughput processors. Due to onboard storage restrictions and telemetry downlink limitations these systems must pre-process and reduce the data before sending it to the ground. This onboard processing and realtime requirement load may mean that newer more powerful processors are needed even though acceptable radiation-hardened versions have not yet been released. CALIPSO's single board computer payload controller processor is actually a set of four (4) voting non-radiation hardened COTS Power PC 603r's built on a single width VME card by General Dynamics Advanced Information Systems (GDAIS). Significant radiation concerns for CALIPSO and other Low Earth Orbit (LEO) satellites include the South Atlantic Anomaly (SAA), the north and south poles and strong solar events. Over much of South America and extending into the South Atlantic Ocean (see figure 1) the Van Allen radiation belts dip to just 200-800km and spacecraft entering this area are subjected to high energy protons and experience higher than normal Single Event Upset (SEU) and Single Event Latch-up (SEL) rates. Although less significant, spacecraft flying in the area around the poles experience similar upsets. Finally, powerful solar proton events in the range of 10MeV/10pfu to 100MeV/1pfu as are forecasted and tracked by NOAA's Space Environment Center in Colorado can result in SingleEvent Upset (SEU), Single Event Latch-up (SEL) and permanent failures such as Single Event Gate Rupture (SEGR) in some technologies. (Galactic Cosmic Rays (GCRs) are another source, especially for gate rupture) CALIPSO mitigates common radiation concerns in its data handling through the use of redundant processors, radiation-hardened Application Specific Integrated Circuits (ASIC), hardware-based Error Detection and Correction (EDAC), processor and memory scrubbing, redundant boot code and mirrored files. After presenting a system overview this paper will expand on each of these strategies. Where applicable, related on-orbit data collected since the CALIPSO initial boot on May 4, 2006 will be noted.

AL/DTA became a major supplier in the field of space cryogenics for the European Space Industry. From MELFI freezer for the International Space Station (ISS) to HERSCHEL and PLANCK satellites for Cosmic Vision, AL/DTA has acquired a large know-how in space cryogenic systems. Convinced by the great interest of Pulse Tube technology for space applications and especially for Earth Observation or Surveillance Tracking, AL/DTA started its first development in mid nineteenths. Then the European Space Agency started to support the development in 2000. Partnerships were launched with CEA/SBT (France) and Thales Cryogenics B.V. (The Netherlands) in order to take the advantage of the competencies and experience of each other. Based on the will to improve important issues such as reliability and mechanical robustness, technology improvements are now available in AL/DTA Pulse Tube coolers. This paper proposes an overview of AL/DTA cryocoolers for space applications following by a detailed description of Pulse Tube Coolers and particularly their integration.

It is uniquely advantaged to monitor and survey the characteristics of seas from the space. The result of the observation of sea surface by using the aircraft-borne and the satellite-borne remote sensors proves that it is feasible to obtain the data of the sea surface temperature and the color by means of remote sensing technology. We can obtain the information about the deposition suspension, the plankton and the chlorophyll, etc. of the sea by the remote sensing application of sea. Then, through the inversion, we can get the chlorophyll density, the sea primarily productive forces and all the essential factors of the water color. This article introduces a new remote sensor of sea environment monitor developed by Shanghai Institute of Technical Physics Academy of Science Marine Aircraft-borne Multi-spectral Scanner (MAMS). We present its main technical specification, performance and use in the article as well.