1. The table includes polar-orbiting sensors that are functional as of May 2006 and for which imagery is readily available. A link is provided to the home page of non-commercial satellites.

2. A "yes" in an applications row means the application is reasonably well founded. A "limited" means the sensor is not optimal for this application but merits consideration.

3. REA compatible sensors are considered by OEA Technologies to be useful for Rapid Environmental Assessment. They have an effective revisit time at mid-latitudes that is at least daily and deliver data in near-real time.

4. Revisit time refers to either the satellite's orbit recycle time or the sensor's effective revisit time (identified with a "~") at mid-latitudes. Revisit time varies with latitude and sensor configuration, and certain programs have a constellation of satellites.

5. Near-real time satellite programs deliver data to the user within two hours of satellite overpass.

6. Type: (Com)mercial, (Met)eorology, (Mil)itary, (R&D) research & development. Imagery produced from commercial satellite sensors must be purchased. R&D satellites are usually owned by space agencies and the imagery is available free-of-charge. Meteorology and Military satellites are owned by public agencies and meet prescribed operational requirements.
7. Errors. Please Contact Us if you observe any errors or omissions in the table.