Landsat satellites provide us with the longest continuous record of remotely sensed earth images. Today NASA and the USGS launched what will be Landsat 8 (if all goes well after a test run of three months). The satellite carries two sensors, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS), which will carry on the Landsat legacy started in 1972. We can’t wait to start getting the new data in about 100 days. . .
See http://www.nasa.gov/mission_pages/landsat/main/index.html for more information.