the result that polar researchers are usually satisfied with the DAAC, whereas researchers in other disciplines often are not. In addition, the authority and budget for the development of software and hardware necessary for the ASF DAAC to succeed is not vested with the DAAC itself, but with the Jet Propulsion Laboratory (JPL) developers. However, responsibility for satisfying users rests with the ASF DAAC. A key recommendation is therefore that NASA grant authority for the operation and development of the facility to the DAAC. Finally, the demand for SAR data from U.S. researchers far exceeds the supply, and the panel urges NASA to formulate and help implement a long-term national policy for the acquisition, processing, and use of SAR data for civilian purposes (i.e., research and commercial operations).

INTRODUCTION

The Alaska Synthetic Aperture Radar Facility was established in a Memorandum of Agreement between the University of Alaska and NASA in 1986. Its mission is to establish, operate, and maintain a receiving, image processing, analysis, and archiving facility for SAR data, which are collected exclusively by foreign spacecraft. JPL designed and installed the data acquisition and management system, and SAR data have been acquired and distributed since 1991. The ASF DAAC was created in 1990, and it now handles the data processing, distribution, and archive for the Alaska SAR Facility. The DAAC's current holdings include data from ERS-1 and 2, JERS-1, and RADARSAT-1 missions.

SAR data are useful for applications ranging from sea-ice dynamics to volcanology to ecosystem change (Box 6.1). Consequently, the user community is small, but growing. Its growth, however, is hindered by data restrictions, which are specified by MOUs between NASA and foreign space agencies.

The ASF DAAC is unique within the EOSDIS system, not only because of its international character, but also because the processing information systems are being developed at JPL, rather than by the EOSDIS Core System (ECS) contractor. Because of delays in the ECS, JPL was tasked with developing an interim information system; the final system will be provided by the ECS contractor if sufficient funds are available. However, the JPL and ECS systems are not interoperable, so the ASF DAAC faces a difficult transition period several years from now if current ECS plans are adhered to. Finally, unlike most other DAACs, the ASF DAAC is currently managing large data streams. As such, it is the first DAAC to try to ''drink from the fire hose,'' and its experience may well be a preview of what other DAACs will face.

The Panel to Review the ASF DAAC held its site visit on December 18–19, 1997. At that time, the management of the ASF DAAC was in transition. This transition has not yet been fully completed. However, many of the fundamental issues raised by the panel pertain more to NASA's long-term development, management, and use of the facility than to the DAAC's operation and will retain



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