The Earth Observing System (EOS) Clearinghouse, or ECHO refers to a system that was used by the National Aeronautics and Space Administration (NASA) to spatially, temporally and otherwise index the petabytes of data that NASA's Earth Science projects collect.
[1] It does not hold the data itself, but serves as a search engine that other applications can access via a web service based interface.
[2] In the late 1990s, NASA recognized that the emerging internet technologies would facilitate a democratization of the access to data.
NASA began the ECHO effort as a prototype, using web technology to allow the public extensive access to data previously only available to researchers.
CMR will be the authoritative management system for all EOSDIS metadata.