Successful science data support for Earth observing satellite missions and their data systems requires a large, well-coordinated set of activities that spans more than the lifetime of the missions. The Distributed Active Archive Center (DAAC) at the GSFC Earth Sciences Data and Information Services Center has been providing such science data support for numerous satellite missions since 1993 (e.g., TOMS, SeaWiFS, TRMM, MODIS). These cradle-to-grave data support activities include user surveys, profiling, and requirements gathering; data ingest, validation, and archive; documentation and informational Web sites; search and order and visualization; read software and other tools; user support; value-added or customized products and services; and outreach. The goal is to enable users to fully realize the scientific, educational, and application potential of DAAC data.

The DAAC's Hydrology Data Support Team has been helping users of Tropical Rainfall Measuring Mission (TRMM) data in achieving this goal since before the launch of TRMM on November 28, 1997. TRMM is a joint mission of the National Aeronautics and Space Administration (NASA) and the National Space Development Agency (NASDA) of Japan to monitor and study tropical and subtropical rainfall systems. TRMM data and information are accessible via http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/hydrology/hd_main.html. This paper summarizes the main components-the anatomy-of TRMM science data support provided by the DAAC, which include (1) pre-launch preparation; (2) first public data release of TRMM standard products, via the TRMM Web Search and Order System; (3) support for two major reprocessings; (4) support for five field validation experiments; (5) a suite of derived subsets; (6) a collection of ancillary and related hydrological data sets; (7) data product readmes and other documentation; (8) read software, Web GIS, data mining, and other tools; and (9) outreach and the continual gathering of user requirements, via usage statistics, conferences, and other means. At all times, the DAAC's TRMM support remains responsive to user needs, accommodating to unanticipated demands, and innovative in availing the users of the latest appropriate technology. Through this support, in the four years of TRMM thus far, the DAAC has largely achieved the goal of enabling an increasing number and variety of users to fully benefit from the use of TRMM data in solving problems.