Launched in a sun-synchronous orbit on December18, 1999 Terra is one of the oldest active satellites in NASA's Earth Observing System (EOS).  Terra is managed by the Goddard Space flight center with contributions from NASA's Jet Propulsion Laboratory and the Langley Research Center as well as the Canadian and Japanese space agencies.
 
Terra carries the first Moderate Resolution Imaging Spectroradiometer (MODIS).  Terra is the EOS-AM satellite which together with the EOS-PM satellite let the MODIS instruments view the entire planet every 1 to 2 days.  Covering a swath width of 2330 km MODIS delivers sea surface temperature, atmospheric temperature, cloud temperature, cloud altitude, water vapor, ocean color and aerosol data.  MODIS sea surface temperature gridded products are available at near real time (link).
 
Terra is the flagship of the EOS, a series of spacecraft that represent a landmark step in NASA's role to observe Earth from the unique vantage point of space.   Terra focuses on measurements identified by a consensus of U.S. and international scientists enabling research into the ways that Earth's lands, oceans, air, ice, and life function as a total environmental system
 
In addition to MODIS Terra will fly with the Clouds and the Earth’s Radiant Energy System (CERES), the Multi-angle Imaging SpectroRadiometer (MISR), the Measurements of Pollution in The Troposphere (MOPITT), and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument.