Advanced Very High Resolution (AVHRR) and Geostationary Operational Environmental Satellite (GOES) imagery, received by antennas located at the University of Colorado, are made available to Internet users through an online data access system. Created as a “testbed” data system for the National Aeronautics and Space Administration's (NASA's) future Earth Observing System Data and Information System (EOSDIS), this testbed provides an opportunity to test both the technical requirements of an online data system and the different ways in which the general user community would employ such a system. Initiated in Dec., 1991 the basic data system experienced 4 major evolutionary changes in response to user requests and requirements. Features added with these changes were the addition of online browse, user subsetting, and dynamic image processing/navigation. Over its lifetime the system has grown to a maximum of over 2,500 registered users and after losing many of these users due to hardware changes, the system is once again growing with its own independent mass storage system.