The Space Physics Archive Search Engine (SPASE) Project for Sun-Earth Connection Data Finding and Retrieval

The diversity of space physics data available electronically has become so great that it is difficult to keep track of what information exists. With current technology it is possible, however, to provide an easy way to determine the existence and location of data of interest via queries to network services with a relatively simple user interface. An international group of space physics data centers is developing such an interface system, called the Space Physics Archive Search Engine (SPASE). Many comprehensive lists of URL's have been put together to provide a minimal search capability for space physics data. One recent effort to gather a list of data sources resulted in an assembly of nearly 100 URL's and many important archives had still been missed. These lists are difficult to maintain and change constantly. However, even with these lists it is not possible to ask a simple question such as "where can I find observations near the polar cusp in 1993?" without doing extensive, manual searches on separate data services. The only hope for a comprehensive, automated search service is to have data centers/archives make their own information available to users in a manner that will facilitate multi-archive searching. Nearly all space physics data providers have WWW services that allow at least a basic search capability, and many also provide more specialized interfaces that support complex queries and/or complex data structures, but each of these services is different. The SPASE effort is creating a simple, XML-based common search capability and a common data dictionary that would allow users to search all participating archives with topics and time frames such as "polar cusp" and "the year 1993". The result would be a list of archives with relevant data. More advanced services at later stages of the project would allow intercomparison of search results to find, for example, overlapping data intervals. Retrieval of the relevant data would also be supported. The first stages of the project are based on testing existing software applications such as the Object Oriented Data Technology (OODT - see http://oodt.jpl.nasa.gov/about.html) for applicability. The initial effort also includes the derivation of a common data dictionary for facilitating the searches. The current state of these efforts and plans for the future will be reviewed.