The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan and designed to monitor and study tropical rainfall and the associated release of energy. TRMM has acquired more than four years of data since its launch in November 1997. All TRMM standard products are processed by the TRMM Science Data and Information System (TSDIS) and archived and distributed to general users by the Goddard Earth Sciences Distributed Active Archive Center (GES DAAC).

The TRMM satellite algorithms are continually being evaluated and improved by the TRMM Science Team. TRMM data are periodically reprocessed to incorporate the improved science algorithms. A brief history of TRMM reprocessing of Product Versions 1 to 5 are provided, including the distinction of Versions 5 and 5A related to TRMM's satellite operating altitude change in 2001. The upcoming TRMM Version 6 reprocessing is discussed, including major changes in the algorithms, improvements to the products, release of new data products, and enhancements to DAAC data access and visualization tools that reflect these changes.