LUNARINFO: A Data Archiving and Retrieving System for the Circumlunar Explorer Based on XML/Web Services

It is essential to build a modern information management system to store and manage data of our circumlunar explorer in order to realize the scientific objectives. It is difficult for an information system based on traditional distributed technology to communicate information and work together among heterogeneous systems in order to meet the new requirement of Internet development. XML and Web Services, because of their open standards and self-containing properties, have changed the mode of information organization and data management. Now they can provide a good solution for building an open, extendable, and compatible information management system, and facilitate interchanging and transferring of data among heterogeneous systems. On the basis of the three-tiered browse/server architectures and the Oracle 9i Database as an information storage platform, we have designed and implemented a data archiving and retrieval system for the circumlunar explorer-LUNARINFO. We have also successfully realized the integration between LUNARINFO and the cosmic dust database system. LUNARINFO consists of five function modules for data management, information publishing, system management, data retrieval, and interface integration. Based on XML and Web Services, it not only is an information database system for archiving, long-term storing, retrieving and publication of lunar reference data related to the circumlunar explorer, but also provides data web Services which can be easily developed by various expert groups and connected to the common information system to realize data resource integration.

Chemical Classification of Space Debris

Space debris, here referring to all non-operating orbital objects, has steadily increased in number so that it has become a potential barrier to the exploration of space. The ever-increasing number of space debris pieces in space has created an increasingly threatening hazard to all on-the-orbit spacecraft, and all future space exploration activities have to be designed and operated with respect to the increasing threat posed by space debris. Generally, space debris is classified as large, medium and small debris pieces based on their sizes. The large debris piece is easily catalogued, but medium to small debris pieces are very difficult to track and also quite different in damage mechanisms from the large ones. In this paper, a scheme of chemical classification of space debris is developed. In our scheme, the first-order classification is employed to divide space debris into two groups: natural micrometeoroids and artificial space debris. The second-order classification is based on their chemical patterns and compositions. The natural micrometeoroids are further divided into three types, namely mafic, metal and phyllosilicate micrometeorites, while the artificial space debris is divided into seven types, which are polymers, non-metal debris, metals and their alloys, oxides, sulphides and their analogs, halides and carbides. Of the latter seven types, some can also be further divided into several sub-types. Chemical classification of space debris is very useful for the study of the chemical damage mechanism of small debris pieces, and also is of great significance in constraining the origin and source of space debris and assessing their impact on spacecraft and human space activities.