What are the main Earth Observation Satellites and Sensors
  
   _Here is a list of some EO missions. These entries should become html
   links to further information (esp. details of imagery and where to get
   it if applicable) on an ad-hoc basis, as and when I have the
   information to put there (contributions sought) and the time to edit
   them in._
   
   For detail on any of the following (and others), try a keyword search
   on Esrin's GDS at http://gds.esrin.esa.it/.
   
   See also http://gds.esrin.esa.it/CIDN_PROVA.source
     * ADEOS Advanced Earth Observing Satellite
          + OCTS Ocean Color and Temperature Scanner
          + AVNIR Advanced Visible and Near-Infrared Radiometer
          + NSCAT NASA Scatterometer
          + TOMS Total Ozone Mapping Spectrometer
          + POLDER Polarization and Directionality of the Earth's
            Reflectance
          + IMG Interferometric Monitor for Greenhouse Gasses
          + ILAS Improved Limb Atmospheric Spectrometer
          + RIS Retroflector in Space
     * Almaz
          + SAR
     * DMSP Defense Meterological Satellite Program
          + SSM/I (Special Sensor Microwave/Imager)
          + Visible
          + SSM/T1, SSM/T2 Microwave temperature & moisture sounders
     * ERS-1 Earth Resources Satellite
          + AMI (Active Microwave Instrument), Wind mode, Wave mode, SAR
            (Synthetic Aperture Radar)
          + Radar Altimeter
          + ATSR-M (Along-Track Scanning Radiometer and Microwave
            Sounder)
          + PRARE (Precise Range & Range Rate Equipment)
     * ERS-2 as ERS1 with addition of
          + GOME Global Ozone Monitoring Experiment
     * GEOS Geodynamics Experimental Ocean Satellite
     * GEOSAT GEOdetic SATellite
     * GMS Geostationary Meteorological Satellites (140 E)
          + VISSR (Visible and Infra-red Spin Scan Radiometer)
     * GOES Geostationary Operational Environmental Satellite (75 W and
       135 W)
          + VISSR (Visible and Infra-red Spin Scan Radiometer) altimeter
     * HCMM Heat Capacity Mapping Mission
          + HCMR (Heat Capacity Mapping Radiometer), visible + thermal
     * INSAT Geostationary satellite of India (74 E)
     * IRS Indian Remote Sensing Satellite System
          + PAN - Panchromatic Camera
          + LISS I - III (Linear Imaging Self Scanning Sensors)
          + WIFS
     * JERS-1 Japanese Earth Resources Satellite
          + OPS Optical Sensors
          + SAR (Synthetic Aperture Radar)
     * KOSMOS Russian EO satellite
     * Landsat
          + TM (Thematic Mapper)
          + MSS (Multi-Spectral Scanner System)
          + RBV (Return Beam Vidicon) camera
     * METEOR Russian meteo satellites (2-21, 3-3, 3-5)
     * Meteosat (0 E, Greenwich meridian)
          + Visible/near infra-red
          + middle IR
          + Watervapour, thermal infra-red
     * MOS Marine Observation Satellite
          + MESSR Multispectral Electronic Self Scanning Radiometer
          + VTIR Visible and Thermal Infrared Radiometer
          + MSR Microwave Scanning Radiometer
     * Nimbus 7
          + CZCS Coastal Zone Color Scanner
          + ERB Earth Radiation Budget
          + LIMS Limb Infra-red Monitor for the Stratosphere
          + SAM-II Stratospheric Aerosol measurement (II)
          + SAMS Stratospheric and Mesospheric Sounder
          + SBUV Solar and Backscatter ultraviolet Spectrometer
          + TOMS (Total Ozone Mapping Spectrometer)
          + SMMR (Scanning Multichannel Microwave Radiometer)
          + THIR Temperature Humidity Infra-red Radiometer
     * NOAA Polar Orbiting Environmental Satellites (series)
          + AVHRR Advanced Very High Resolution Radiometer
          + TOVS (TIROS Operational Vertical Sounder)
          + SBUV/2 Solar Backscatter Ultraviolet Spectrometer
     * Radarsat (Canada) 
          + SAR
     * RESURS
          + MSU-E High resolution optical scanner
          + MSU-SK Medium-resolution Optical-IR
     * SeaStar
          + SeaWiFS Sea-viewing Wide Field-of-view Sensor
     * SeaSat Ocean Dynamics Satellite
          + SAR L-band
          + ALT Radar altimeter
          + SASS Radar Scatterometer
          + SMMR Scanning Multi-Spectral Microwave Radiometer
          + VIRR Visible en Infra-red Radiometer
     * Shuttle
          + SIR-A Shuttle Imaging Radar
          + SIR-B
          + SIR-C (cross polarized returns VH and HV) (Apr+Oct 1994)
          + LFC Large Format Camera
          + MOMS Modular Opto-electronic Multi-spectral Scanner (2 bands)
     * SkyLab
          + S 192 MSS Multispectral Scanner
          + Metric camera experiment
     * SPOT
          + HRV High Resolution Visible (2x) has 2 modes:
               o XS (MultiSpectral mode)
               o PAN (PANchromatic mode)
     * SPOT 4 (launch 1995)
          + HRVIR High Resolution Visible and Infrared
     * TIROS, TOS and ITOS forerunners of the current NOAA series
       (9-12+14, 13 failed just after launch). See NOAA above.
          + AVHRR Advanced Very High Resolution Radiometer
          + TOVS (TIROS Operational Vertical Sounder) consisting of:
               o HIRS/2 infra-red sounder
               o SSU stratospheric sounding unit
               o MSU microwave sounding unit
     * TOPEX/POSEIDON
          + ALT Radar Altimeter
          + TMR TOPEX Microwave Radiometer
          + LRA Laser Retroreflector Array
          + SSALT Single-Frequency Solid-State Radar Altimeter
          + DORIS Dual-Doppler Tracking System Receiver
          + GPSDR GPS Demonstration Receiver
     * TRMM Tropical Rainfall Measuring Mission (launch 1997, Japan)
          + PR Precipitation Radar
          + TMI TRMM Microwave Imager
          + VIRS Visible Infrared Scanner
          + CERES Clouds and the Earth's Radiant Energy System
          + LIS Lightning Imaging Sensor
       
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