Summary: The National Aeronautics and Space Administration's (NASA) plans for a $3 billion project to process, store, and distribute information generated by the Earth Observing System--a program to collect data on changes in the planet's atmosphere, oceans, and continents--falls short in identifying and mitigating the technological risks inherent in a project of such scope and complexity. GAO recommends that NASA not award the Earth Observing System Data Information System (EOSDIS) contract until specific plans have been developed and resources identified for (1) prototyping the full range of critical system elements and (2) guiding and accelerating research into key advanced technologies essential for the system's ultimate success. In addition, NASA should work to maximize cooperation with other federal agencies and earth science programs having data system experience in global change-related areas. Without specific plans and resources in place to ensure that emerging user needs are met and key technical challenges aggressively pursued and resolved, NASA is running an unnecessarily high risk that EOSDIS may not meet future global change research needs and may require costly modifications to be useful. GAO summarized this report in testimony before Congress; see: Earth Observing System: NASA Needs to Reassess Its EOSDIS Development Strategy, by Samuel W. Bowlin, Director of Defense and Security Information Systems Issues, before the Subcommittee on Science, Technology, and Space, Senate Committee on Commerce, Science, and Transportation. GAO/T-IMTEC-92-7, Feb. 26, 1992 (eight pages); and Earth Observing System: NASA Needs to Reassess Its EOSDIS Development Strategy, by Samuel W. Bowlin, Director of Defense and Security Information Systems Issues, before the Subcommittee on Space, House Committee on Science, Space, and Technology. GAO/T-IMTEC-92-8, Feb. 27, 1992 (eight pages).