It is now common for academic institutes, government sectors and commercial corporations all over the world to engage in collaborative, complex applications. Most of them require international and interoperable access to large quantities of distributed, heterogeneous geospatial data, services, computing abilities and other facilities. The Open Grid Services Architecture (OGSA) implemented through the Globus Toolkit, provides an applicable and convenient software infrastructure for securely sharing computational resources within a Virtual Organization. In this paper, based on the Globus Toolkit, we propose an open, reusable, optimized, standards-compliant, and Grid-enabled geospatial software system for archiving, managing, querying and serving NASA earth observing system data. We apply Grid technologies to OGC Web services to make them Grid-enabled and deploy them into the system. These services can be invoked either by OGC users or by Grid users in the Grid environment. Any OGSA-compliant Grid services can be deployed into the system, and can invoke or be invoked by our or other Grid services in our Virtual Organization to securely access each other?s data and other computational resources after we authorize access. A Catalogue Service Federation (CSF) with an OGC standard interface is developed to interact with other Grid or non-Grid geospatial catalogue services for querying and serving much more geospatial data. An intelligent Grid Service Mediator (iGSM) and Replica Optimization Service (ROS), both of which are Grid services, are proposed to distribute and optimize user requests for data and services in the system. All of the Grid-enabled geospatial services can be reused to construct more complex and functional services by forming a service-chain.