The Living Planet Programme of the European Space Agency encompasses a science-driven strategy for monitoring the Earth from space. The Earth Explorer missions are defined, developed and operated in close cooperation with the science community and focus on the key components of the Earth System: the atmosphere, biosphere, hydrosphere, cryosphere and the Earth's interior. The emphasis of these missions is on providing data to advance our understanding of these individual components, their interaction with each other and the impacts that human activities have on natural Earth processes. By involving the science community from the beginning and introducing a peer-reviewed selection process, this ongoing user-driven approach has given the Earth science community an efficient tool in their endeavor to better understand and monitor our planet. So far, this process has resulted in six missions currently under development: GOCE, Cryosat, ADM Aeolus, SMOS, Swarm and EarthCARE. The third cycle of Earth Explorers Core Missions was started in 2005 to select the seventh Earth Explorer mission due to launch in 2014/2015. At present there are six candidate missions being assessed at pre-phase A level. These missions were chosen to enter the assessment phase as a result of the Call for Core Mission ideas released by ESA in 2005, which resulted in 24 proposals out of which six candidates were selected: - BIOMASS - global measurements of forest biomass and extent; - TRAQ - (TRopospheric composition and Air Quality) - Air quality monitoring and long-range transport of air pollutants; - PREMIER - (PRocess Exploration through Measurements of Infrared and millimetre-wave Emitted Radiation) Understanding the processes that link trace gases, radiation, chemistry and climate in the atmosphere; - FLEX - (FLuorescence EXplorer) - Observation of global photosynthesis through the measurement of fluorescence; - A-SCOPE - (Advanced Space Carbon and Climate Observation of Planet Earth) - Improving the understanding of the global carbon cycle and regional carbon dioxide fluxes; - CoReH₂O - (Cold Regions Hydrology High-resolution Observatory) - Detailed observations of key snow, ice and water cycle characteristics. This paper presents an overview of the six candidate missions, describing the scientific objectives and outlining the main aspects of the candidate implementation concept currently under evaluation.

The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) program. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. This paper describes the Sentinel-1 mission, an imaging synthetic aperture radar (SAR) satellite constellation at C-band. It provides an overview of the mission requirements, its applications and the preliminary technical concept for the system.

ADM-Aeolus is a dedicated satellite to provide global observations of vertical wind profiles. It will demonstrate the capability of a spaceborne Doppler wind lidar to accurately measure wind profiles. Thus the mission addresses one of the major deficiencies of the present Global Observing System. Simulations show that the wind profiles from Aeolus will improve Numerical Weather Prediction analyses and forecasts in the tropics and extra tropics. Aeolus is a precursor for an operational wind profiler system. It is under development for the European Space Agency with Astrium Satellites as prime contractor. Launch is planned in 2009 for a 3 year mission. There is likely to be a significant gap between the nominal end of life of Aeolus in late 2012, and the availability of wind profiles from post-EPS instruments in 2019 or later. The presentation will sketch a programme to fill this gap. It is based on copies of the present Aeolus satellite with minor modifications, such as finer vertical sampling, an alternative line-of-sight, and measures to increase lifetime. The programmatics required to fill the data gap will be discussed.

EUMETSAT has initiated preparatory activities for the definition of the follow-on EUMETSAT Polar System (post- EPS) needed for the timeframe 2020 onwards as a replacement for the current EUMETSAT Polar System. Based on the first outputs of the EUMETSAT post-EPS user consultation process initiated in 2005, mission requirements for potential post-EPS missions have been drafted. Expertise from a variety of communities was drawn upon in order to ascertain user needs expressed in terms of geophysical variables, for operational meteorology, climate monitoring, atmospheric chemistry, oceanography, and hydrology. Current trends in the evolution of these applications were considered in order to derive the necessary satellite products that will be required in the post-EPS era. The increasing complexity of models with regard to parameterisation and data assimilation, along with the trend towards coupled atmosphere, ocean and land models, generates new requirements, particularly in the domains of clouds and precipitation, trace gases and ocean/land surface products. Following the requirements definition, concept studies at instrument and system levels will shortly commence with the support of the European Space Agency (ESA), together with industry and representatives of the user and science communities. Such studies, planned for completion by end of 2008, aim at defining and trading off possible mission and system concepts and will establish preliminary functional requirements for full or partial implementation of post-EPS mission requirements. Cost drivers and needs for critical research and development will also be identified. The generation of both the user and mission requirements have been supported substantially by the post-EPS Mission Experts Team and the Application Expert Groups. Their support is gratefully acknowledged.

ESA and EUMETSAT have initiated joint preparatory activities for the formulation and definition of the Meteosat Third Generation (MTG) geostationary system to ensure the continuity and improvement of the Meteosat Second Generation (MSG) system. The MTG will become the new system to be the backbone of the European operational meteorological services from 2015, in particular, will ensure the continuation of the imagery missions. The first phases were devoted to the definition and consolidation of end user requirements and priorities in the field of Nowcasting and Very Short Term Weather Forecasting (NWC), Medium/Short Range global and regional Numerical Weather Prediction (NWP), Climate and Air Composition Monitoring and to the definition of the relevant observation techniques. The following missions have been analysed and preliminary concepts studied: - High Resolution Fast Imagery Mission (successor to MSG SEVIRI HRV mission) - Full Disk High Spectral Resolution Imagery Mission (successor to the mission of other MSG-SEVIRI channels) - Lightning Imagery Mission - IR Sounding Mission - UV-VIS-NIR Sounding Mission After pre-phase A mission studies (2003-2006), where preliminary instrument concepts were investigated allowing in the same time to consolidate the technical requirements for the overall system study, a phase A study on MTG has been launched at the beginning of February 2007 for the space segment system feasibility and programmatic aspects to be accomplished during 2007-2008 time frame. The space segment phase A study will cover all elements to the level of details allowing to conclude on the feasibility of the system and to produce cost estimates with a good level of confidence. This paper addresses an overview of the outcome of the MTG space segment progress (spacecraft concept, payload preliminary design studies) accomplished in the frame of the phase A. It namely focuses onto the Imaging and IR Sounding Missions, highlights the platform and resulting instrument concepts, establishes the critical technologies and introduces the study progress towards the implementation of the MTG development programme.

In addition to five years of routine operations of SCIAMACHY on-board of ESA's ENVISAT mission, the launches of the TerraSAR-X and RapidEye missions and the beginning of both their operational phases are the major milestones for the German Space Programme in 2007 and 2008. These two missions will contribute significantly to the European GMES-Initiative and to the Global Earth Observation System of Systems (GEOSS) and enhance the knowledge about state and dynamics of the Earth's system. Both missions are implemented under public-private-partnership between government and industry, an innovative economic scheme for space mission implementation. With the TanDEM-X and the Hyperspectral EnMAP mission this efficient way of sharing competences, costs and responsibilities on one hand and benefits on the other hand will be further followed. In addition, with MetImage Germany started the development of an imaging radiometer for the European post-EPS satellite system of EUMETSAT. These five attractive missions are important contributions of the German Earth Observation Community to the global system. This investment underlines the political objective of Europe and Germany to advance the environmental agenda. In parallel technology developments for next generation Earth Observation instruments have started, namely High Resolution Wide Swath SAR (Synthetic Aperture Radar), IR detectors and coolers, optical components and mechanisms for LEO and GEO and high power Mixed Garnet laser transmitters for LIDAR (Light Detecting and Ranging) applications. With these activities Germany will be able to provide future Earth Observation missions with suitable technologies as an answer to the increasing complexity of user requirements. In this paper the objectives and the strategy of the German Earth Observation Programme will be explained and the main elements, i.e. missions and technology developments as well as the plans for the future will be introduced.

The department of Optical Information Systems (OS) at the Institute of Robotics and Mechatronics of the German Aerospace Center (DLR) has more than 25 years experience with high-resolution imaging technology. The technology changes in the development of detectors, as well as the significant change of the manufacturing accuracy in combination with the engineering research define the next generation of spaceborne sensor systems focusing on Earth observation and remote sensing. The combination of large TDI lines, intelligent synchronization control, fast-readable sensors and new focal-plane concepts open the door to new remote-sensing instruments. This class of instruments is feasible for high-resolution sensor systems regarding geometry and radiometry and their data products like 3D virtual reality. Systemic approaches are essential for such designs of complex sensor systems for dedicated tasks. The system theory of the instrument inside a simulated environment is the beginning of the optimization process for the optical, mechanical and electrical designs. Single modules and the entire system have to be calibrated and verified. Suitable procedures must be defined on component, module and system level for the assembly test and verification process. This kind of development strategy allows the hardware-in-the-loop design. The paper gives an overview about the current activities at DLR in the field of innovative sensor systems for photogrammetric and remote sensing purposes.

TROPOMI is a nadir-viewing grating-based imaging spectrograph in the line of OMI and SCIAMACHY. TROPOMI is part of the ESA Candidate Core Explorer Mission proposal TRAQ and also of the CAMEO satellite proposed for the US NRC decadal study. A TROPOMI-like instrument is part of the ESA/EU Sentinel 4&5 pre-phase A studies. TROPOMI covers the OMI wavelengths of 270-490 nm to measure O3, NO2, HCHO, SO2 and aerosols and adds a NIR channel and a SWIR module. The NIR-channel (710-775 nm) is used for improved cloud detection and aerosol height distribution. The SWIR module (2305 - 2385 nm) measures CO and CH4 and forms a separate module because of its thermal requirements. TROPOMI is a non-scanning instrument with an OMI-like telescope but optimized to have smaller ground pixels (10 x 10 km²) and sufficient signal-to-noise for dark scenes (albedo 2 %). TROPOMI has the same wide swath as OMI (2600 km). In TRAQ's mid-inclination orbit, this allows up to 5 daytime observations over mid-latitude regions (Europe, North-America, China). The paper gives a description of the TROPOMI instrument and focuses on several important aspects of the design, for example the sun calibration and detector selection status.

The Microwave Humidity Sounder (MHS) is the high-frequency microwave radiometer of the ATOVS (Advanced TIROS Operational Vertical Sounder) instrument suite of the IJPS (Initial Joint Polar System), the current joint EUMETSAT-NOAA programme for operational satellite meteorology. Five MHS models have been built by Astrium Ltd under EUMETSAT contract, two of which are currently operational on the NOAA-18 and Metop-A satellites. The MHS instrument replaces the former AMSU-B in the operational microwave sounder suite. This paper provides a summary description of the MHS instrument and describes in some detail its in-orbit performance and functionality, along with a comparison with similar instruments. The in-orbit performance has been extensively assessed during the SIOV (Satellite In-Orbit Verification), the first part of the commissioning phase aimed at activating the payload and verifying its operation, and is periodically monitored throughout the mission life. The performance relevant to the SIOV and operational phase of the MHS instruments on both NOAA-18 and Metop-A are presented. With respect to its predecessor AMSU-B, the MHS instrument constitutes a sensible improvement in terms of radiometric sensitivity and calibration accuracy, while allowing full continuity of the acquired data and relevant processing.

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 24th 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 2008-2013 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.

For the effective evaluation of the hazard, the data should have been acquired before the hazard occurrence and should be quickly acquired after it. While there have been a lot of discussions on application of remote sensing data to hazard evaluation, there are few results on effective application of remote sensing data. To fulfill the first condition, it is necessary to have world coverage of data. For the second condition, flexible and timely data acquisition is mandatory. ASTER seems to fulfill the both conditions. In case of the giant landslide (Hattian slide) occurred in Pakistan on October 8, 2005, the data acquired before and just after the landslide are both available. And the damage was quantitatively evaluated by using DEM generated from ASTER stereo pairs obtained before and after it.

This paper describes the updated results of calibration and validation for optical instruments onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi"), which was successfully launched on January 24th, 2006 and continuously works very well. ALOS has an L-band Synthetic Aperture Radar called PALSAR and two optical instruments 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 panchromatic radiometers, and is used to derive a digital surface model (DSM) with high spatial resolution that is an objective of the ALOS mission. The geometric calibration is important in generating a precise DSM by stereo pair image of PRISM. AVNIR-2 has four radiometric bands from blue to near infrared and uses for regional environment and disaster monitoring etc. The radiometric calibration is also important for AVNIR-2 as well as PRISM. This paper describes updated results of the radiometric calibration of AVNIR-2, and geolocation determination accuracy evaluation as a part of geometric calibration, and validation of generated DSM by PRISM. These works will be done during the ALOS mission life as operational calibration to keep absolute accuracies of the standard products.

The Greenhouse gases Observing Satellite (GOSAT) is a Japanese satellite that is intended to observe CO₂ concentrations from space and to contribute to advancement of research related to CO₂ source/sink estimation. The GOSAT main sensor is a Fourier Transform Spectrometer (FTS) named "TANSO-FTS", which covers a wide terrestrial radiation spectrum including CO₂ absorption bands at 1.6 μm (Short Wavelength InfraRed, SWIR), and 15 μm (Thermal InfraRed, TIR). The former band is used to estimate columnar concentration of CO₂; the latter is used to retrieve the vertical profile of CO₂ in the upper atmosphere above the ca. 700 hPa pressure level. We adopt the maximum a posteriori method (MAP) to retrieve the vertical profile of CO₂ concentrations using the meteorological analysis data for temperature profiles. Key techniques for retrieving CO₂ concentrations are 1) reduction of temperature estimation error through channel selection, 2) optimization of the a priori CO₂ profile based on the output from a CO₂ transport model, and 3) usage of SWIR data as an additional constraint in retrieval of vertical profiles of CO₂. Simulation studies using the output from a CO₂ transport model show that, although thermal infrared spectrum has poor sensitivity to the CO₂ concentration change in the lower atmosphere, particularly in the boundary layer, we expect that CO₂ concentration profiles in the lower atmosphere can be reproduced statistically by combining CO₂ columnar data derived from SWIR as an additional constraint in retrieving a CO₂ concentration profile from TIR data.

Greenhouse gases Observing SATellite (GOSAT) is a Japanese mission to observe greenhouse gases, such as CO₂ and CH₄, from space. The GOSAT carries a Fourier transform spectrometer and a push broom imager. The GOSAT development is going on in phase-C/D and characterized the sensor performance in laboratory. In orbit, the observation data will be evaluated by onboard calibration data and implemented by ground processing system. The post-launch calibration items are planned and the methods will be developed before the launch. The methods are investigated by analyzing the current MODIS data, which has similar wavelength bands to GOSAT. In this paper, we show the calibration plans of pre-flight test, onboard calibration, and post-launch vicarious calibration of GOSAT sensors.

GOSAT Project is a joint project of MOE (Ministry of the Environment), JAXA (Japan Aerospace Exploration Agency) and NIES (National Institute for Environmental Studies). Data acquired by TANSO-FTS (Fourier Transform Spectrometer) and TANSO-CAI (Cloud and Aerosol Imager) on GOSAT will be collected at Tsukuba Space Center at JAXA. The level 1A and 1B data of FTS (interferogram and spectra, respectively) and the level 1A of CAI (uncorrected data) will be generated at JAXA and will be transferred to GOSAT Data Handling facility (DHF) at NIES for further processing. Radiometric and geometric correction will be applied to CAI L1A data to generate CAI L1B data. From CAI L1B data, cloud coverage and aerosol information (CAI Level 2 data) will be estimated. The FTS data that is recognized to have "low cloud coverage" by CAI will be processed to generate column amount of carbon dioxide CO₂ and methane CH₄ (FTS Level 2 data). Level 3 data will be "global map column amount" of green house gases averaged in time and space. Level 4 data will be global distribution of carbon source/sink model and re-calculated forward model estimated by inverse model. Major data flow will be also described. The Critical Design Review of the DHF was completed in the end of July of 2007 to prepare the scheduled launch of GOSAT in December 2008. The data products can be searched and will be open to the public through GOSAT DHF after the data validation process.

The Global Precipitation Measurement (GPM) mission started as an expanded follow-on mission of the Tropical Rainfall Measuring Mission (TRMM) project to obtain more accurate and frequent observations of precipitation than TRMM. An important goal for the GPM mission is the frequent measurement of global precipitation using a GPM core satellite and a constellation of multiple satellites. The GPM core satellite is developed by the US and Japan as like as TRMM, while the constellation satellites are developed by various countries. The accurate measurement of precipitation will be achieved by the Dual-frequency Precipitation Radar (DPR) installed on the GPM core satellite. DPR consists of two radars, which are Ku-band (13.6 GHz) precipitation radar (KuPR) and Ka-band (35.5 GHz) radar (KaPR). KaPR will detect snow and light rain, and the KuPR will detect heavy rain. In an effective dynamic range in both KaPR and KuPR, drop size distribution (DSD) information and more accurate rainfall estimates will be provided by a dual-frequency algorithm. The frequent precipitation measurement every three hours at any place on the globe will be achieved by several constellation satellites with microwave radiometers (MWRs). JAXA/EORC is responsible for the GPM/DPR algorithm development for engineering values (Level 1) and physical products (e.g. precipitation estimation) (Level 2 and 3) and the quality control of the products as the sensor provider. It is also important for us to produce and deliver 3-hourly global precipitation map in real time in order to make useful for various research and application areas (i.e., the prediction of the floods). To secure the quality of estimates, the mission must place emphasis on validation of satellite data and retrieval algorithms.

Japan Aerospace Exploration Agency (JAXA) has been proposing the Global Change Observation Mission (GCOM). GCOM will consist of two series of medium size satellites: GCOM-W (Water) and GCOM-C (Climate). The mission will take over the Advanced Earth Observing Satellite-II (ADEOS-II or Midori-II). The GCOM-W1 satellite (the first generation of GCOM-W series) was approved by the Space Activities Commission of Japan to proceed to the development phase. Current target of launch date is the beginning of 2012. The Advanced Microwave Scanning Radiometer-2 (AMSR2) is sole mission instrument onboard the GCOM-W1 satellite. Although the simultaneous observation by a microwave scatterometer and AMSR2 is still desired, installation of the scatterometer is not the case at least for the GCOM-W1 satellite. AMSR2 is a successor of the AMSR for the EOS (AMSR-E) provided to the NASA Aqua satellite and AMSR onboard Midori-II with some improvements based on the experiences of AMSR and AMSR-E. They include an improvement of calibration system and an addition of 7.3 GHz channels to help mitigating radio-frequency interference issue. The AMSR-E instrument is still providing continuous data records more than 5-years. Observed brightness temperatures and retrieved geophysical parameters are being widely used for monitoring environmental changes and for applying to the operational applications such as numerical weather forecasting. We expect a long-term continuity by leading the GCOM-W/AMSR2 to the AMSR-E observation.

The Fourth Assessment Report of IPCC predicted that global warming is already happening and it should be caused from the increase of greenhouse gases by the extension of human activities. These global changes will give a serious influence for human society. Global environment can be monitored by the earth observation using satellite. For the observation of global climate change and resolving the global warming process, satellite should be useful equipment and its detecting data contribute to social benefits effectively. JAXA (former NASDA) has made a new plan of the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation GLI) onboard GCOM-C (Climate) satellite, which is one of this mission, provides an optical sensor from Near-UV to TIR. Characteristic specifications of SGLI are as follows; 1) 250 m resolutions over land and area along the shore, 2) Three directional polarization observation (red and NIR), and 3) 500 m resolutions temperature over land and area along shore. These characteristics are useful in many fields of social benefits. For example, multi-angular observation and 250 m high frequency observation give new knowledge in monitoring of land vegetation. It is expected that land products with land aerosol information by polarization observation are improved remarkably. We are studying these possibilities by ground data and satellite data.

The Japan Aerospace Exploration Agency (JAXA) has the plan of the Global Change Observation Mission (GCOM) for monitoring global environmental change. Second generation Global Imager (SGLI) is a mission instrument to be installed on the satellite of GCOM Mission Climate (GCOM-C) satellite. SGLI is the optical radiometer observed to the frequent Global, Ocean, Land, Cloud and Ice sphere to help determine the Earth's climate change. SGLI is a suite of two radiometers called VNR and IRS. The VNR is employing a wide swath (1150km) push-bloom scan with line CCD detector. IRS is employing a conventional cross-track mirror scan system (1400km swath) with cooled infrared detector. We report the SGLI preliminary design and special feature. The current SGLI is BBM development phase which is underway to confirm the feasibility of the design.

The paper presents the present status, scientific tentative results, plan of the future Japanese satellite missions related to the cloud sciences. There are three missions that will contribute to the cloud observations; GOSAT, EarthCARE, and GCOM-C (-W). Among the sensors aboard the satellites, we focus on the multi-spectral imagers. Each imager has different number of bands and observation swath according to the primary objectives. A principal aim of the CAI/GOSAT, for the cloud application, is providing the cloud screening to mitigate the uncertainty of CO₂ retrieval by the FTS aboard the GOSAT. The MSI/EarthCARE will observe quasi-3D field of clouds together with active sensors, CPR and ATLID. The SGLI/GCOM-C, the follow-on mission of GLI/ADES-II, is the most precision imager among all Japanese future multi-spectral imagers. It has 19 bands from 380nm to 12μm, two of polarization bands.

It is now possible to combine high spectral resolution observations (like AIRS) with moderate spatial resolution (like MODIS) in a single instrument. The ARIES instrument concept provides over 3000 spectral channels in the 0.4 - 15.4 μm spectral region with spatial resolution of 1.0 km while still scanning ±55°. The ARIES has size and mass less than half that of AIRS or MODIS primarily due to the advancements in focal plane assemblies and wide field optical systems developed under the NASA IIP and in US industry. The combined capability will allow more cloud free observations per unit area, and improve the overall cloud-clearing approach applied on AIRS. It will also improve sensitivity to atmospheric water vapor, temperature and trace gases in the boundary layer and facilitate studies of surface and atmospheric interaction for global climate studies. Improvements are expected in regional weather forecasts and hurricane prediction. This paper discusses the primary requirements for ARIES, the expected science and operational benefits and an instrument concept that demonstrates the viability and low risk of the approach.

Spectrometers, in which a grating is coupled with a two dimensional detector array to provide high resolution spectra without the need for spectral scan mechanisms can be designed in compact, rugged, configurations, making them well suited for spaceborne spectral mapping applications. We are pursuing the use of this technology for spaceborne tropospheric air quality monitoring, targeting high spectral resolution solar reflective and thermal emission spectroscopy in the wavelength range 2 to 5 μm. In this region key tropospheric pollutant and greenhouse gases such as O₃, CO, CO₂, CH₄, HCHO, and H₂O, have strong spectral features. The relatively short wavelengths allow for the use of well-developed detector technology and passive cooling. With sufficient resolving power, sensitivity, and judicious combination of spectra, good information on tropospheric vertical distributions, including boundary layer data, can be obtained. This paper describes the performance characteristics of a laboratory prototype of such a spectrometer, focused on the measurement of CO spectra in the range 4.56 to 4.73 μm. The design uses a cooled grating and optical train, coupled with a cooled 1024 x 1024 pixel HgCdTe array. It achieves a spectral resolution of ~0.32 cm^-1 and NESR of 5.8x10^-9 w/cm2/sr/cm^-1. Both laboratory absorption spectra and zenith-looking air emission spectra of CO are presented. The spectrometer is the pre-cursor to a combined 4.6/2.33 μm instrument being developed under NASA funding and designed to demonstrate the unique vertical information capability of such a combination for tropospheric CO measurement. We give a brief discussion of a spaceborne concept focused on this technique.

Nowadays, CMOS image sensors are widely considered for space applications. Their performances have been significantly enhanced with the use of CIS (CMOS Image Sensor) processes in term of dark current, quantum efficiency and conversion gain. Dynamic Range (DR) remains an important parameter for a lot of applications. Most of the dynamic range limitation of CMOS image sensors comes from the pixel. During work performed in collaboration with EADS Astrium, SUPAERO/CIMI laboratory has studied different ways to improve dynamic range and test structures have been developed to perform analysis and characterisation. A first way to improve dynamic range will be described, consisting in improving the voltage swing at the pixel output. Test vehicles and process modifications made to improve voltage swing will be depicted. We have demonstrated a voltage swing improvement more than 30%. A second way to improve dynamic range is to reduce readout noise A new readout architecture has been developed to perform a correlated double sampling readout. Strong readout noise reduction will be demonstrated by measurements performed on our test vehicle. A third way to improve dynamic range is to control conversion gain value. Indeed, in 3 TMOS pixel structure, dynamic range is related to conversion gain through reset noise which is dependant of photodiode capacitance. Decrease and increase of conversion gain have been performed with different design techniques. A good control of the conversion gain will be demonstrated with variation in the range of 0.05 to 3 of initial conversion gain.

It is generally known that active pixel sensors (APS) have a number of advantages over CCD detectors if it comes to cost for mass production, power consumption and ease of integration. Nevertheless, most space applications still use CCD detectors because they tend to give better performance and have a successful heritage. To this respect a change may be at hand with the advent of deep sub-micron processed APS imagers (< 0.25-micron feature size). Measurements performed on test structures at the University of Delft have shown that the imagers are very radiation tolerant even if made in a standard process without the use of special design rules. Furthermore it was shown that the 1/f noise associated with deep sub-micron imagers is reduced as compared to previous generations APS imagers due to the improved quality of the gate oxides. Considering that end of life performance will have to be guaranteed, limited budget for adding shielding metal will be available for most applications and lower power operations is always seen as a positive characteristic in space applications, deep sub-micron APS imagers seem to have a number of advantages over CCD's that will probably cause them to replace CCD's in those applications where radiation tolerance and low power operation are important

SELEX S&AS is developing a family of infrared sensors for earth observation missions. The spectral bands cover shortwave infrared (SWIR) channels from around 1μm to long-wave infrared (LWIR) channels up to 15μm. Our mercury cadmium telluride (MCT) technology has enabled a sensor array design that can satisfy the requirements of all of the SWIR and medium-wave infrared (MWIR) bands with near-identical arrays. This is made possible by the combination of a set of existing technologies that together enable a high degree of flexibility in the pixel geometry, sensitivity, and photocurrent integration capacity. The solution employs a photodiode array under the control of a readout integrated circuit (ROIC). The ROIC allows flexible geometries and in-pixel redundancy to maximise operability and reliability, by combining the photocurrent from a number of photodiodes into a single pixel. Defective or inoperable diodes (or "sub-pixels") can be deselected with tolerable impact on the overall pixel performance. The arrays will be fabricated using the "loophole" process in MCT grown by liquid-phase epitaxy (LPE). These arrays are inherently robust, offer high quantum efficiencies and have been used in previous space programs. The use of loophole arrays also offers access to SELEX's avalanche photodiode (APD) technology, allowing low-noise, highly uniform gain at the pixel level where photon flux is very low.

For the next generation of ELOP Payloads, a new focal plane array and new detector has been designed. The new detector design and its modes of operation will be described. The focal plane design was also affected by the payload telescope design. The anastigmat three-mirror telescope (ATMT) design - which was chosen for the payload - does not allow any refractive elements in the focal plane, hence a new mechanical butting solution - differing from the classical block-based format - was applied and qualified. In order to reduce analog noise, the detector pins will be connected directly to the focal plane electronics board using a qualified connector and procedure. This technique simplifies the detector replacement process, in case of detector failure during integration. The large number of detectors and the high pixel rate produce significant heat dissipation which has to be removed. The focal plane heat removal concept will be described. The ATMT design results in an off-axis detector position and due to the wide field of view (FOV) of the camera, distortion effects must be taken into account, especially in the case of 96 row TDI detectors. The impact on system Modulation Transfer Function (MTF), both in the scan direction and along the detector line direction, will be described. In order to reduce these effects, a curved focal plane is needed; hence, special care was taken in the design of the detector butting angles. The residual MTF contribution of the curved focal plane is presented.

Since 2002, the THALES Group has been manufacturing sensitive arrays using QWIP technology based on GaAs and related III-V compounds, at the Alcatel-Thales-III-V Lab (formerly part of THALES Research and Technology Laboratory). In the past researchers claimed many advantages of QWIPs. Uniformity was one of these and has been the key parameter for the production to start. Another widely claimed advantage for QWIPs was the so-called band-gap engineering and versatility of the III-V processing allowing the custom design of quantum structures to fulfil the requirements of specific applications such as very long wavelength (VLWIR) or multispectral detection. In this presentation, we give the status of our LWIR QWIP production line, and also the current status of QWIPs for MWIR (<5μm) and VLWIR (>15μm) arrays. As the QWIP technology cannot cover the full electromagnetic spectrum, we develop other semiconductor compounds for SWIR and UV applications. We present here the status of our first FPA realization in UV with GaN alloy, and at 1.5μm with InGaAs photodiodes.

Sofradir started to work in the field of space applications and especially in the earth observation domain in the beginning of the 1990th. 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 has become 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 and more based on qualified Mercury Cadmium Telluride (MCT) technology. As a matter of fact, Sofradir is involved in several projects for future space missions (SPIRALE, Bepi Colombo, MTG, SGLI...). This paper proposes an overview of Sofradir technology capabilities and experience for design of custom space detectors. In particular this paper presents latest developments for space applications with new results in visible, long wavelength and space qualification of infrared detectors.

The Japanese Aerospace Exploration Agency (JAXA) will be conducting the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation Global Imager) is an optical sensor on board GCOM-C (Climate), that includes a Long Wave IR Detector (LWIRD) sensitive up to about 13 μm. SGLI will provide high accuracy measurements of the atmosphere (aerosol, cloud ...), the cryosphere (glaciers, snow, sea ice ...), the biomass and the Earth temperature (sea and land). Sofradir is a major supplier of Space industry based on the use of a Space qualified MCT technology for detectors from 0.8 to 15 μm. This mature and reproducible technology has been used for 15 years to produce thousands of LWIR detectors with cut-off wavelengths between 9 and 12 μm. NEC Toshiba Space, prime contractor for the Second Generation Global Imager (SGLI), has selected SOFRADIR for its heritage in space projects and Mercury Cadmium Telluride (MCT) detectors to develop the LWIR detector. This detector includes two detection circuits for detection at 10.8 μm and 12.0 μm, hybridized on a single CMOS readout circuit. Each detection circuit is made of 20x2 square pixels of 140 μm. In order to optimize the overall performance, each pixel is made of 5x5 square sub-pixels of 28 μm and the readout circuit enables sub-pixel deselection. The MCT material and the photovoltaic technology are adapted to maximize response for the requested bandwidths: cut-off wavelengths of the 2 detection circuits are 12.6 and 13.4 μm at 55K. This detector is packaged into a sealed housing for full integration into a Dewar at 55K. This paper describes the main technical requirements, the design features of this detector, including trade-offs regarding performance optimization, and presents preliminary electro-optical results.

IASI (Infrared Atmospheric Sounding Interferometer) is an infrared atmospheric sounder. The IASI instrument is currently operating on the Metop-A satellite (launched in October 2006). The core of the instrument is composed of a Fourier transform infrared spectrometer. The detection chain of the spectrometer includes 3 bands to cover the 3.4 to 15.5 μm spectral range. For each band, the IR detection is made by a 2 x 2 pixels array operating at ~93K. This paper presents an analysis of the radiation tolerance of the infrared detectors for each band. On ground, radiation tests have been performed to address sensitivity to gamma-rays and protons radiations. A special care has been taken to keep the detectors at cold temperature during tests. Performance evolutions (responsivity, relative spectral response, noise,... tested in CNES facilities) before and after radiations are given. First in orbit impacts of the radiations are also reviewed.

Thanks to important development efforts completed and partial ESA funding, Air Liquide Advanced Technology Division (AL/DTA), is now in position to propose two Pulse Tube cooler systems in the 40-80K temperature range for coming Earth Observation missions such as Meteosat Third Generation, Sentinel 3, etc... The two pulse tube coolers thermo-mechanical units are qualified against environmental constraints. The associated Cooler Drive Electronics is also an important aspect specifically regarding the active control of the cooler thermo-mechanical unit during the launch phase, the active reduction of the vibrations induced by the compressor (partly supported by the French Agency CNES) of course the electrical interfaces with the compressor. This paper details the presentation of the two Pulse Tube Coolers together with the Cooler Drive Electronics aspects.

The fast development of nitrides has given the opportunity to investigate AlGaN as a material for ultraviolet detection. Such camera present an intrinsic spectral selectivity and an extremely low dark current at room temperature. It can compete with technologies based on photocathodes, MCP intensifiers, back thinned CCD or hybrid CMOS focal plane arrays (FPA) for low flux measurements. AlGaN based cameras allow UV imaging without filters or with simplified ones in harsh solar blind conditions. Few results on camera have been shown in the last years, but the ultimate performances of AlGaN photodiodes couldn't be achieved due to parasitic illumination of multiplexers, responsivity of p layers in p-i-n structures, or use of cooled readout circuit. Such issues have prevented up to now a large development of this technology. We present results on focal plane array of 320x256 pixels with a pitch of 30μm for which Schottky photodiodes are multiplexed with a readout circuit protected by black matrix at room temperature. Theses focal plane present a peak reponsivity around 280nm and 310nm with a rejection of visible light of four decades only limited by internal photoemission in contact. Then we will show the capability to outdoor measurements. The noise figure is due to readout noise of the multiplexer and we will investigate the ultimate capabilities of Schottky diodes or Metal- Semiconductor-Metal (MSM) technologies to detect extremely low signal. Furthermore, we will consider deep UV measurements on single pixels MSM from 32nm to 61nm in a front side illumination configuration. Finally, we will define technology process allowing backside illumination and deep UV imaging.

The microbolometer spectrometer breadboard MIBS is a prism spectrometer that uses an uncooled microbolometer detector array and has been designed for the ESA EarthCARE mission. In order to demonstrate its feasibility a breadboard has been build, and tests have been performed that show good correlation between predicted and achieved results. Although application for EarthCARE has become uncertain due to geodistribution issues, it is feld that this instrument (which is small enough to give grown up performance to a micro satellite) has a lot of application potential for applications like weather forecasting and forest fire detection. The presentation will elaborate on performance predicted, measurements performed, results achieved and future applications.

STSAT-3, a ~150kg micro satellite, is the third experimental microsatellite of the STSAT series designated in the Long- Term Plan for Korea's Space Development by the Ministry of Science and Technology of Korea. The STSAT-3 satellite was initiated in October 2006 and will be launched into a lower sun-synchronous earth orbit (~ 700km) in 2010. This paper presents a brief introduction of STSAT-3 and also introduces its secondary payload, i.e. COMIS, a compact imaging spectrometer, which was inspired by the success of CHRIS, a previous PROBA payload. COMIS takes hyperspectral images of 30m/60m ground sampling distance over a 30km swath width. The number of bands is selectable among 18 or 62. COMIS takes hyper-spectral images in two different modes: a) Pushbroom and b) multi-directional observation. The payload will be used for environmental monitoring, such as in-land water quality monitoring of Paldang Lake located next to Seoul, the capital of South Korea.

Passive cooling has shown to be a very dependable cryogenic cooling method for space missions. Several missions employ passive radiators to cool down their delicate sensor systems for many years, without consuming power, without exporting vibrations or producing electromagnetic interference. So for a number of applications, passive cooling is a good choice. At lower temperatures, the passive coolers run into limitations that prohibit accommodation on a spacecraft. The approach to this issue has been to find a technology able to supplement passive cooling for lower temperatures, which maintains as much as possible of the advantages of passive coolers. Sorption cooling employs a closed cycle Joule-Thomson expansion process to achieve the cooling effect. Sorption cells perform the compression phase in this cycle. At a low temperature and pressure, these cells adsorb the working fluid. At a higher temperature they desorb the fluid and thus produce a high-pressure flow to the restriction in the cold stage. The sorption process selected for this application is of the physical type, which is completely reversible. It does not suffer from degradation as is the case with chemical sorption of e.g. hydrogen in metal hydrides. Sorption coolers include no moving parts except for some check valves, they export neither mechanical vibrations nor electromagnetic interference, and are potentially very dependable due to their simplicity. The required cooling temperature determines the type of working fluid to be applied. Sorption coolers can be used in conjunction with passive cooling for heat rejection at different levels. This paper starts with a brief discussion on applications of passive coolers in different types of orbits and the limitations on passive cooling at low cooling temperatures. Next, the working principle of sorption cooling is summarized. The DARWIN mission is chosen as an example application of sorption and passive cooling and special attention is paid to the reduction of the radiator area needed by the sorption cooler. By examining the performance of alternative working fluids suitable for different cooling temperatures, the application field of this type of sorption cooling is currently expanded.

Launched in April 1999, Landsat-7 ETM+ continues to acquire data globally. The Scan Line Corrector in failure in 2003 has affected ground coverage and the recent switch to Bumper Mode operations in April 2007 has degraded the internal geometric accuracy of the data, but the radiometry has been unaffected. The best of the three on-board calibrators for the reflective bands, the Full Aperture Solar Calibrator, has indicated slow changes in the ETM+, but this is believed to be due to contamination on the panel rather then instrument degradation. The Internal Calibrator lamp 2, though it has not been used regularly throughout the whole mission, indicates smaller changes than the FASC since 2003. The changes indicated by lamp 2 are only statistically significant in band 1, circa 0.3% per year, and may be lamp as opposed to instrument degradations. Regular observations of desert targets in the Saharan and Arabian deserts indicate the no change in the ETM+ reflective band response, though the uncertainty is larger and does not preclude the small changes indicated by lamp 2. The thermal band continues to be stable and well-calibrated since an offset error was corrected in late-2000. Launched in 1984, Landsat-5 TM also continues to acquire global data; though without the benefit of an on-board recorder, data can only be acquired where a ground station is within range. Historically, the calibration of the TM reflective bands has used an onboard calibration system with multiple lamps. The calibration procedure for the TM reflective bands was updated in 2003 based on the best estimate at the time, using only one of the three lamps and a cross-calibration with Landsat-7 ETM+. Since then, the Saharan desert sites have been used to validate this calibration model. Problems were found with the lamp based model of up to 13% in band 1. Using the Saharan data, a new model was developed and implemented in the US processing system in April 2007. The TM thermal band was found to have a calibration offset error of 0.092 W/m² sr µm (0.68K at 300K) based on vicarious calibration data between 1999 and 2006. The offset error was corrected in the US processing system on April 2007 for all data acquired since April 1999.

Launched in May 2002, the Aqua MODIS has successfully operated on-orbit for more than five years and continuously produced many high quality data products that have significantly contributed to studies of the Earth's climate and environmental changes. The MODIS collects data in 36 spectral bands ranging from the visible (VIS) to the long-wave infrared (LWIR) spectral region and at three (nadir) spatial resolutions: 250m (2 bands), 500m (5 bands), and 1km (29 bands). Bands 1-19 and 26 are the reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μm and bands 20-25 and 27-36 are the thermal emissive bands (TEB) with wavelengths from 3.7 to 14.4μm. The MODIS on-board calibrators, noticeably improved over those of its heritage sensors, include a solar diffuser (SD), a solar diffuser stability monitor (SDSM), a blackbody (BB), a spectro-radiometric calibration assembly (SRCA), and a space view (SV) port. This paper provides an overview of Aqua MODIS on-orbit operation and calibration activities with emphasis on the performance of its on-board calibrators. Results discussed in this paper include TEB and RSB detector noise characterization, short-term stability and long-term response change. The sensor's overall spectral (RSB) and spatial (RSB and TEB) parameters are also presented in this paper.

Since launch, both Terra and Aqua MODIS have been making regular lunar observations with a primary objective of providing an independent stability monitoring for the reflective solar bands (RSB) calibration. To a large extent, this approach is based on the fact that the Moon has extremely stable surface reflectance properties. When combined with a lunar radiometric model, the applications of lunar observations can be significantly enhanced. Using MODIS as an example, this paper discusses various applications developed from its lunar observations. In addition to the RSB stability monitoring, MODIS lunar observations are regularly used to examine its calibration consistency between Terra and Aqua MODIS and to track the sensor's band-to-band registration (BBR) stability. Examples also presented in this paper include optical leak and electronic crosstalk characterization for MODIS thermal emissive bands (TEB) and shortwave infrared (SWIR) bands. Results from multi-year lunar observations show that the MODIS RSB calibration stability has been satisfactory when compared to its solar calibration, and that Terra and Aqua MODIS are calibrated consistently to within ±1% for most RSB. The spatial characterization results derived from MODIS lunar observations agree very well with that determined from its on-board calibrator. It is clear that the applications and results of MODIS lunar observations presented here will serve as good examples or references for other sensors that also make use of lunar surface observations.

MODIS is a scanning radiometer that uses a two-sided scan mirror, making the Earth view (EV) observations over an angular range of ±55° relative to instrument nadir. The 16 thermal emissive bands (TEB) are calibrated on a scan-by-scan basis using a quadratic algorithm that includes corrections for the sensor response versus scan angle (RVS). Currently, there are two MODIS instruments operated on-orbit. For Terra MODIS (launched in December 1999), the TEB RVS was characterized on-orbit using deep space observations made during spacecraft maneuvers. For Aqua MODIS (launched in May 2002), the TEB RVS was measured pre-launch. In this paper, we describe an approach used to monitor the on-orbit stability of MODIS TEB RVS using observations made during its data sector rotation (SR). The SR is implemented via flight software commands, during which the EV data collection is purposely shifted such that the EV data is taken when the sensor actually views the instrument scan cavity. We will show that this approach can accurately determine the TEB RVS differences between the mirror sides and track the TEB RVS changes on-orbit.

ALISEO (Aerospace Leap-frog Imaging Stationary Interferometer for Earth Observation) belongs to the stationary interferometers representing a promising architecture for future Earth Observation (EO) sensors due to their simple optical layout. ALISEO has been selected by the Italian Space Agency as the principal payload for a new optical mission based on a micro-satellite (MIOsat). Payloads planned for MIOsat are an extensible telescope, a high-resolution panchromatic camera, a Mach-Zehnder MEMS interferometer, and ALISEO. MIOsat is expected to provide a platform with pointing capability for those advanced sensors. ALISEO operates in the common-path Sagnac configuration, and it does not employ any moving part to generate phase delay between the two rays. The sensor acquires the target images modulated by a pattern of autocorrelation functions: a fringe pattern that is fixed with respect to the instrument's field of view. The complete interferogram of each target location is retrieved introducing relative source-observer motion, which allows any image pixels to be observed under different phase delays. Recent laboratory measurements performed with ALISEO are described and discussed in this paper. In order to calibrate the optical path difference (OPD) of raw interferograms, a set of measurements have been carried out using a double planar diffuser system and several coloured He-Ne lasers. Standard reflectance tiles together doped with Holmium and Rare Earths have been used for validating the wavelength calibration of the instrument and proving the reliability of the reflectance retrieving procedure.

We present a simple, spreadsheet-based model to examine the effects of the spectral response functions of individual instrument bands on their measurements of top-of-the-atmosphere radiances. The model uses spectral radiances at 1 nm resolution from the near ultraviolet to the shortwave infrared at wavelengths from 300 nm to 2500 nm, convolving them with the spectral responses of the bands to calculate band-average spectral radiances. For on-orbit calibration purposes, the model uses nominal solar irradiance and lunar albedo spectra to provide saturation, diffuser, and lunar radiances for the bands. For prelaunch calibration purposes, the model uses a 2850K Planck function, normalized to a maximum value of unity, to approximate the spectral shape from a laboratory integrating sphere source. For Earth-exiting radiances, the model uses nominal radiance spectra over a blue ocean, a desert, and a grassland. These spectra are provided with the effects of atmospheric trace gas absorption removed. In addition, the model includes a trace gas transmittance spectrum that can be modified as a function of airmass. Currently, a spectrum with an airmass of 2.4 is used. In the model, this transmittance spectrum is combined with the three Earth-exiting radiance spectra to provide top-of-the-atmosphere radiance spectra both with and without trace gas absorption features. Here we use the model to investigate three types of spectral response features. The first study involves the out-of-band response from one of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) bands. Using the model, we demonstrate a technique to correct for the effect of that response on measurements of Earth-exiting radiances. The second study shows the effect of in-band spectral differences in an instrument band with multiple detectors. In this example, the effects are small, but differ with the type of Earth scene and with the amount of atmospheric trace gas absorption. On-orbit corrections for portions these detector-to-detector spectral differences are possible. However, at some level these differences will cause a residual striping in the band's measurements that cannot be removed. The final study examines measurements by a proposed multispectral grating-based spectrometer of the wavelength region near 760 nm, where there is a substantial absorption feature from atmospheric oxygen. Based on the bandwidth and wavelength spacing of the instrument's bands, we investigate the use of the absorption feature to provide a wavelength calibration for the instrument. This model provides a tool for use in the design of new satellite instruments. In addition, it is possible to use the model to help mitigate the effects of actual spectral response features in instrument bands after those features are revealed during prelaunch characterization.

Improperly imaged, or scattered, optical radiation within an instrument is difficult to properly characterize and is often the dominant residual source of measurement error. Scattered light can originate from the spectral components of a "point" source and from spatial elements of an extended source. The spectral and spatial scattered light components are commonly referred to as stray light and can be described by an instrument's spectral line spread function (SLSF) and point spread function (PSF), respectively. In this paper, we present approaches that characterize an instrument's response to scattered light and describe matrices that have been developed to correct an instrument's response for this scattered light. Examples are given to demonstrate the efficacy of the approach and implications for remote sensing instruments are discussed.

For the past decade, the Marine Optical Buoy (MOBY), a radiometric buoy stationed in the waters off Lanai, Hawaii, has been the primary in-water oceanic observatory for the vicarious calibration of U. S. satellite ocean color sensors, including the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Moderate Resolution Imaging Spectrometers (MODIS) instruments on the National Aeronautics and Space Administration's (NASA's) Terra and Aqua satellites. The MOBY vicarious calibration of these sensors supports international effort to develop a global, multi-year time series of consistently calibrated ocean color data products. A critical component of the MOBY program is establishing radiometric traceability to the International System of Units (SI) through standards provided by the U. S. National Institute of Standards and Technology (NIST). A detailed uncertainty budget is a core component of traceable metrology. We present the MOBY uncertainty budget for up-welling radiance and discuss additional considerations related to the water-leaving radiance uncertainty budget. Finally, we discuss approaches in new instrumentation to reduce the uncertainties in in situ water-leaving radiance measurements.

The ESA-PRODEX funded MEDUSA project aims to develop a light weight high resolution multi-spectral earth observation instrument, which will be embarked on a solar-powered high altitude long endurance (HALE) UAV, operated at stratospheric altitudes (15 to 18km). The MEDUSA instrument is designed to fill the gap between traditional airborne and spaceborne instruments regarding resolution and coverage. It targets applications such as crisis management and cartography, requiring high resolution images with regional coverage, flexible flight patterns, high update rates and long mission lengths (weeks to months). The MEDUSA camera is designed to operate at a ground resolution of 30 cm at 18 km altitude in the visible spectrum (400-650 nm), and a swath of 3000m. The central part of the payload is a focal plane assembly consisting of two frame sensors (PAN and RGB). The wide swath is realized with a custom designed highly sensitive CMOS sensor of 10000x1200 pixels. A GPS receiver and Inertial Measurement Unit (IMU) provide accurate position and attitude information. A direct downlink allows near-real time data delivery to the user. The on-board data processing consists mainly of basic image corrections and data compression (JPEG2000). The challenge lies mainly in fulfilling the requirements within the extreme environmental and physical constraints of the HALE UAV. Compared to traditional airborne and spaceborne systems, the MEDUSA camera system is ultra light weight (about 2 kg) and is operated in a low pressure and low temperature environment. System modeling and simulation is used to make careful trade-offs between requirements and subsystem performances. On 27th November 2006 the phase C/D for the design, production and test of the camera has started at VITO with the support of 9 industrial partners. The MEDUSA camera is expected to transmit its first images the end of 2008.

The Mars Infrared MApper (MIMA) is a FT-IR miniaturised spectrometer which is being developed for ESA ExoMars Pasteur mission. The Martian Infrared MApper Fourier Spectrometer is designed to provide remote measurements of mineralogy and atmosphere of the scene surrounding a Martian rover and guide it to key targets for detailed in situ measurements by other rover experiments. Among the main scientific objectives of the MIMA instrument are to assist the rover in rock/soils selection for further in-situ investigation and to identify rocks and soils on the Martian surface which provide evidence of past/present biological activity. The instrument is also designed to measure the water vapour abundance and vertical distribution and its diurnal and seasonal variation, dust opacity, optical properties, composition, diurnal and seasonal variation. The instrument is a double pendulum interferometer providing spectra in the 2 - 25 μm wavelength domain with a resolving power of 1000 at 2 μm and 80 at 25 μm. The radiometric performances are SNR > 40 in the near infrared and a NEDe = 0.002 in the thermal region. The instrument design is very compact, with a total mass of 1kg and an average power consumption of 5 W.

The Mars Infrared MApper (MIMA) is a FT-IR miniaturised spectrometer which is being developed for ESA ExoMars Pasteur mission. MIMA will be mounted on the rover mast and so it must be compact and light-weight. The scientific goals and its thermo-mechanical design are presented in two companion papers [1] and [2]. In this work the optical design will be reviewed and the results of the tests performed on some optical components will be presented. The design has faced challenging constraints mainly linked to the requirement of keeping the performances good enough to fulfil the scientific objectives of the mission, while, at the same time, it was imperative to keep the overall size and weigh within the allocated resources. In addition the instrument must be able to operate in the very harsh environment of the Martian surface and to withstand, without permanent damage, even harsher conditions as well as the severe dynamic loads expected at landing on Mars. The chosen solution is a single channel double pendulum interferometer, covering the spectral range between 2 and 25 micron, crucial for the scientific interpretation of the recorded spectra, with a resolution variable between 10 and 5 cm-1. Since the spectral range is too wide to be covered by a single detector, it has been decided to use two different detectors, mounted side by side, in a customised case. Such innovative solution has obviously pros and cons and the optical design has been driven by the need to reduce the inconveniences, while maintaining the advantages.

The Mars Infrared MApper (MIMA) is a FT-IR miniaturized spectrometer which is being developed for ESA ExoMars Pasteur mission. MIMA will be mounted on the rover mast and so it must be compact and light-weight. The scientific goals and its optical design are presented in two companion papers [1] [2]; the focus of this work is on the thermomechanical design and testing. The instrument design faces challenging constraints both from the expected environment and the allocated resources. The temperatures during operation are expected to be from -120 °C to +30 °C with the presence of a low density but thermally effective atmosphere. Severe dynamic loads are foreseen during launch and moreover at landing on Mars. The overall size is limited to an envelope of 140 mm x 140 mm x 120 mm and the mass to less than 1 kg. The expected performances of this instrument should be comparable with those of much heavier ones built in the past. An instrument compliant with these constraints has been conceived, introducing many innovative solution with respect to the past experiences and making use of intensive modeling and testing to prove the survival to the harsh environment. Among the most challenging problems the mounting of the brittle KBr optics and the matching of its thermal expansion coefficient with that of the supporting aluminium structure, in a temperature interval of more than 200 °C. Most of the components have undergone thermovacuum tests in the low temperature range because none of them was expected to be used in the -100 °C range.

The TROPOMI instrument concept is part of the TRAQ mission proposal to ESA in response to the Call for Ideas in 2005. TRAQ (TRopospheric composition and Air Quality) has been accepted for a further pre-phase A study for the next Earth Explorer core Mission. A very similar instrument has been proposed for the CAMEO platform to the US National Research Council decadal study, which has also been accepted for further study. TROPOMI is a nadir-viewing grating-based imaging spectrometer using the Dutch OMI and SCIAMACHY heritage. It includes an UV-VIS-NIR module that consists of three UV-VIS channels continuously covering the 270-490 nm range to determine O₃, NO₂, HCHO, SO₂, aerosols and a NIR-channel covering 710-775 nm for cloud detection and information on the aerosol height distribution using the oxygen A band. TROPOMI also includes a SWIR module covering 2305-2385 nm that mainly focuses on determination of CO and CH₄ total columns. All species are measured with sensitivity down to the Earth's surface, thus addressing issues of anthropogenic emissions and their impact on air quality and climate. In the TRAQ mission, unique diurnal time sampling with up to 5 daytime observations over midlatitude regions (Europe, North-America, China) is foreseen by using a non-sun-synchronous, medium-inclination drifting orbit and a 2600 km wide observational swath. Several more general aspects related to the TROPOMI instrument are discussed in a separate paper in this conference. This paper focuses on the development of the SWIR module. A breadboard model (BBM) has been designed and constructed which is as much as possible functionally flight representative. Critical technologies to be demonstrated with the BBM are the SWIR HgCdTe-based 2D focal plane array, the on-board SWIR calibration LED, and in particular, the SRON/TNO developed silicon-based immersed grating that allows a hugely reduced instrument volume. In the presentation the results of a performance analysis of the TROPOMI-SWIR channel will be discussed, as well as results of the detector characterization program on a representative off-the-shelf FPA, and details of the photolithographic production of the immersed grating.

TELIS (TErahertz and submm LImb Sounder) is a three-channel balloon-borne heterodyne spectrometer for atmospheric research. The observational techniques of TELIS can be compared to the presently flying MLS instrument on board NASA's EOS-Aura satellite, but TELIS is built with a new generation of cryogenic heterodyne detectors and novel compact systems suitable for integration into the confined space of a balloon borne cryostat. TELIS will fly on the MIPAS-B2 gondola. The two instruments together will yield the most complete set of stratospheric constituents, measured so far. TELIS is a cooperation between the European institutes DLR (PI-institute), RAL and SRON. First flight foreseen in the spring of 2008 from Teresina, Brasil. The three TELIS receivers provide simultaneous vertical profile measurement of a range of molecules. The 500 GHz channel is developed by RAL and will produce vertical profiles of BrO, ClO, O₃ and N₂O. The 1.8 THz channel is developed by DLR and will mainly target the OH radical, and will also measure HO₂, HCl, NO, NO₂, O₃, H₂O, O₂ and HOCl. Finally the 480 - 650 GHz channel is developed by SRON and IREE and will measure profiles of ClO, BrO, O₃, HCl, HOCl, H₂O and its 3 isotopomers, H₂O₂, NO, N₂O, HNO₃, CH₃Cl and HCN. In this paper, the science and technology of TELIS will be discussed with emphasis on the channel developed by SRON. It contains a Superconducting Integrated Receiver (SIR), which combines on a 4x4 mm² chip the low-noise SIS mixer and its quasioptical antenna, a superconducting phase-locked Flux Flow Oscillator (FFO) acting as Local Oscillator (LO) and a SIS harmonic mixer (HM) for FFO phase locking. The latest results from the pre-flight test and integration campaigns will be presented.

With hyperspectral pushbroom imaging spectrometers it is possible to identify ground pixels by their spectral signature. The Imaging Spectral Signature Instrument (ISSI) concept performs optical on-board processing of the hyperspectral data to identify pixels with a pre-defined and programmable spectral signature. An aircraft compatible breadboard of ISSI has been developed and manufactured. It consists of an objective, which images an object line on the input slit of a first imaging spectrograph, which disperses each pixel of the object line into its spectral content on a liquid-crystal spatial light modulator. This component is programmed with a spatial transmission behaviour, which is constant along the spatial pixels and equal to the spectral filter vector of the searched specific signature along the spectral pixels. A second inverted spectrograph re-images the transmitted flux into a line of pixels on a CCD detector. ISSI operates at wavelengths between 470 nm and 900 nm. The spectral filter vector can be selected for 800 spatial pixels with a spectral resolution of better than 4 nm and almost 8 bit modulation capability. ISSI effectively performs the spectral angle mapping (SAM) operation used in hyperspectral data processing. The signatures are acquired with ISSI in a spectrometer operating mode. The breadboard has undergone a test program consisting of calibration and verification of the spectral, spatial and radiometric performance and object identification capability.

A spatial heterodyne spectrometer (SHS) has significant advantages for high spectral resolution imaging over narrow pre-selected bands compared to traditional solutions. Given comparable optical étendue at R~6500, a field-widened SHS will have a throughput-resolution product ~170 x larger than an air-spaced etalon spectrometer, and ~1000 x larger than a standard grating spectrometer. The monolithic glass Michelson design and lack of moving parts allows maximum stability of spectral calibration over the mission life. For these reasons, SHS offers considerable advantages for the core spectrometer instrument in the European Space Agency's (ESA) Fluorescence Explorer (FLEX) mission.

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/storage. KOMPSAT-2 was launched on July 28 2006 and stared early operation including Initial Activation and Checkout(IAC). During IAC phase, MSC was checked and tested by prepared procedure. In this paper, the preparation, the sequence and the procedure of MSC initial activation checkout including SOH (State Of Health) are described. The activities including the checkout results during IAC as parts of Launch & Early Operation Period (LEOP) are discussed and analyzed.

In 2013 an important ESA Core Explorer Mission, EarthCARE is scheduled to be launched. EarthCARE, (the Earth, Clouds, Aerosol and Radiation Explorer) will comprise two active (a cloud-profiling radar (CPR) and an high spectral resolution atmospheric lidar (ATLID)) and two passive (a Multi-spectral imager (MSI) and a Broad-Band Radiometer (BBR)) instruments. With these, EarthCARE will enable cloud and aerosol properties retrievals consistent with a Top-of-Atmospheric (TOA) flux accuracy of 10 Wm-². This will be achieved by simultaneously probing the atmosphere vertically with the active instruments in synergy with the passive instruments. In order to facilitate and optimize algorithm development and to quantify the effect of different instrument configurations on the mission performance a simulator for EarthCARE (ECSIM) has been developed. ECSIM relies strongly upon a previous prototype developed by ESA/KNMI where a combination of forward and retrieval models (full End-to-End capabilities) have been included. In order to make this tool more useful within the scientific and engineering communities, the prototype simulator has been embedded into a completely reorganized architecture intended to improve a number of aspects: *Complex algorithms have been enclosed within logical entities: models. *Models are connected in a logical sequence with well-defined interfaces. *Users can customize almost every mode's parameter values using configuration XML files. *Model outputs are well documented and stored in easy to access NetCDF files. *Complex simulations can be built up with a few mouse clicks. *Users can run lengthy simulations automatically iterating through different parameter values. *ECSIM can intercept and classify information and error messages from the simulations. *A database is maintained with all the information generated by the system. *It is possible to add third-party algorithms or tools to convert, analyze and visualize data extracted from generated products.

Multi-Spectral Camera(MSC) is a main payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/ storage. The compression method on KOMPSAT-2 MSC was selected and used to match EOS input rate and PDTS output data rate on MSC image data chain. At once the MSC performance was carefully handled to minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP and Cal./Val.(Calibration and Validation) phase. In this paper, on-orbit image data chain in MSC and image data processing on KGS including general MSC description is briefly described. The influences on image performance between on-board compression algorithms and between performance restoration methods in ground station are analyzed, and the relation between both methods is to be analyzed and discussed.

Among all trace gases, the carbon dioxide and methane provide the largest contribution to the climate radiative forcing and together with carbon monoxide also to the global atmospheric carbon budget. New Micro Earth Observation Satellite (MEOS) mission is proposed to obtain information about these gases along with some other mission's objectives related to studying cloud and aerosol interactions. The miniature suit of instruments is proposed to make measurements with reduced spectral resolution (1.2nm) over wide NIR range 0.9μm to 2.45μm and with high spectral resolution (0.03nm) for three selected regions: oxygen A-band, 1.5μm-1.7μm band and 2.2μm-2.4μm band. It is also planned to supplement the spectrometer measurements with high spatial resolution imager for detailed characterization of cloud and surface albedo distribution within spectrometer field of view. The approaches for cloud/clear-sky identification and column retrievals of above trace gases are based on differential absorption technique and employ the combination of coarse and high-resolution spectral data. The combination of high and coarse resolution spectral data is beneficial for better characterization of surface spectral albedo and aerosol effects. An additional capability for retrieval of the vertical distribution amounts is obtained from the combination of nadir and limb measurements. Oxygen A-band path length will be used for normalization of trace gas retrievals.

An airborne imaging Fabry-Perot Interferometer (FPI) system was developed within NASA's Instrument Incubator Program (IIP) to mitigate risk associated with implementation of such a device in future space-based atmospheric remote sensing missions. This system is focused on observing tropospheric ozone through measuring a narrow spectral interval within the strong 9.6 micron infrared ozone band at high spectral resolution, while the concept and technology also have applicability toward measurement of other trace species and other applications. The latest results from laboratory testing and characterization of enabling subsystems and the overall instrument system will be reported, with an emphasis placed on testing performed to evaluate system-level radiometric, spatial, and spectral measurement fidelity.

A constellation of satellites that routinely and frequently images the Earth's land surface in consistently calibrated wavelengths from the visible through the microwave and in spatial detail that ranges from submeter to hundreds of meters would offer enormous potential benefits to society. A well-designed and effectively operated land surface imaging satellite constellation could have great positive impact not only on the quality of life for citizens of all nations, but also on mankind's very ability to sustain life as we know it on this planet long into the future. The primary objective of the Committee on Earth Observation Satellites (CEOS) Land Surface Imaging (LSI) Constellation is to define standards (or guidelines) that describe optimal future LSI Constellation capabilities, characteristics, and practices. Standards defined for a LSI Constellation will be based on a thorough understanding of user requirements, and they will address at least three fundamental areas of the systems comprising a Land Surface Imaging Constellation: the space segments, the ground segments, and relevant policies and plans. Studies conducted by the LSI Constellation Study Team also will address current and shorter-term problems and issues facing the land remote sensing community today, such as seeking ways to work more cooperatively in the operation of existing land surface imaging systems and helping to accomplish tangible benefits to society through application of land surface image data acquired by existing systems. 2007 LSI Constellation studies are designed to establish initial international agreements, develop preliminary standards for a mid-resolution land surface imaging constellation, and contribute data to a global forest assessment.

The outcomes of the 19th Committee on Earth Observing Satellites (CEOS) Plenary held in London in November 2005, recognized that the CEOS Implementation Plan for Space-Based Observations for Global Earth Observation System of Systems (GEOSS) should: - identify the supply of space-based observations required to satisfy the requirements expressed by the 10-year implementation plan for GEOSS; and - propose an innovative process whereby the many disparate types of Earth observing programs funded by CEOS Member agencies might contribute to the supply of the required observations. The CEOS Task Force charged with drafting the CEOS Implementation Plan for Space-Based Observations for GEOSS focused its early efforts on the creation of a 'new planning process' which would satisfy the various criteria demanded by member space agencies, and which would hopefully encourage a new phase of specificity and focus in the multi-lateral co-operation efforts undertaken by space agencies under the CEOS umbrella - resulting in improved engagement of all CEOS Members and real implementation results. The CEOS Constellations is the title given to this new process, and four pilot studies have been initiated in order to pioneer and test the concept. The Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) were selected as the lead agencies for the study of the development of a CEOS Precipitation Constellation with the support of other CEOS space agency and user community participants. The goals, approach, and anticipated outcomes for the study will be discussed.

The Global Earth Observation System of Systems (GEOSS) is a distributed system of systems built on current international cooperation efforts among existing Earth observing and processing systems. The goal is to formulate an end-to-end process that enables the collection and distribution of accurate, reliable Earth Observation data, information, products, and services to both suppliers and consumers worldwide. One of the critical components in the development of such systems is the ability to obtain seamless access of data across geopolitical boundaries. In order to gain support and willingness to participate by countries around the world in such an endeavor, it is necessary to devise mechanisms whereby the data and the intellectual capital is protected through procedures that implement the policies specific to a country. Earth Observations (EO) are obtained from a multitude of sources and requires coordination among different agencies and user groups to come to a shared understanding on a set of concepts involved in a domain. It is envisaged that the data and information in a GEOSS context will be unprecedented and the current data archiving and delivery methods need to be transformed into one that allows realization of seamless interoperability. Thus, EO data integration is dependent on the resolution of conflicts arising from a variety of areas. Modularization is inevitable in distributed environments to facilitate flexible and efficient reuse of existing ontologies. Therefore, we propose a framework for modular ontologies based knowledge management approach for GEOSS and present methods to enable efficient reasoning in such systems.

The Earth Science (ES) community has two major IT related concerns: Modeling, which requires vast amounts of computational resources, and exploration and production of large shared data sets. Both can be accomplishable by Grid infrastructure. Grid or Grid computing is a metaphor name for making computer power as easy to access as an electric power Grid). Different Grid middleware software solutions exist and are being developed. DEGREE (Dissemination and Exploitation of Grids in Earth sciencE) aims to disseminate and promote uptake of Grid in ES and to create a bridge between ES and Grid communities to ensure the next Grid generation will integrate ES application requirements in the middleware and services. In order to achieve this, DEGREE will: identify key ES requirements, disseminate ES application requirements to Grid projects, evaluate Grid middleware tools and standards regarding ES requirements and provide feedbacks to Grid developers. In order to convey requirements to the Grid community, test suite specifications are developed. A test suite specification consists of documentation and an application suitable for testing, including the data needed. Eight test suite specifications are developed and made available by DEGREE for Grid middleware developers. Results will be used to support the development of the ES Grid vision.

Due to the regulation of the ICAO (International Civil Aviation Organization), which requires the provision of electronic terrain data with a certain quality by each contracting state for its territory, the demand for terrain data for aviation purposes increases. This regulation poses a problem particularly for developing and newly industrialising countries, which have not the financial resources for the generation of terrain data meeting the required specifications. Studies performed at the Institute of Flight Systems and Automatic Control at the Technische Universitaet Darmstadt show that a promising and cost-effective method to encounter this challenge is the use of high resolution optical satellite imagery with a stereoscopic coverage. This method can be performed without the acquisition of ground control points and leads by this to cost reductions. To validate this method, the accuracy of terrain data generated from satellite imagery is analysed. Due to the various available very high resolution satellites, the accuracy is not limited by the spatial resolution of the imagery, but principally by the accuracy of the geolocation. This is why furthermore methods are proposed that may help to increase the accuracy, to eliminate blunders as well as systematic errors and thus to enhance the reliability of the acquired terrain information in order to achieve applicability in aviation.

In the radio optically active detection and ranging of objects a signal from an investigated object at the noise background should be recognized. This noise may be the background created both by a foreign source and the background from the underlying surface, on which the object being studied is located. Using the source polarization of a sensing signal of optical radar and polarization elements of the receiver, we can increase the value of the signal from the studied object as compared with the noise background. The versions of the efficiency increase of research tools of active radio and optical sensing are considered at the following conditions: 1. The background from the external source is known. 2. The scattering matrix of underlying surface creating the background is known. 3. The scattering matrix of underlying surface creating the background is unknown. 4. The external source and underlying surface present the background source: a) the Stokes vector of external source and the scattering matrix of underlying surface are known; b) the Stokes vector of external source and the scattering matrix of underlying surface are unknown; c) the Stokes vector of external source is known and the scattering matrix of underlying surface is unknown and vice versa.

Based on a novel method for overcoming DC drift in RF subcarrier phase detection scheme for fibre optic sensors in this paper we propose an improved method for the measurement of small displacements and vibrations. The method works in open loop and is characterized by low distortions in the modulation process, good signal-to-noise ratio and rather low cost. Considering the receiver ideal, we obtained for the measurements of small distances a minimum of 0.74 μm with a 6.6 × 10^-7 dB dynamic range. Also, we evaluated the probability density and modelled it vs the phase error for different values of the average number of photoelectrons generated by the signal and the phase noise parameter. The presented system can be exploited in the measurement of small distances, vibrations and seismic detection.