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Paper: The Monitoring and Trends Databases for the Chandra X-Ray Observatory
Volume: 281, Astronomical Data Analysis Software and Systems XI
Page: 341
Authors: Wolk, S. J.; Cresitello-Dittmar, M.; Estes, A.; Overbeck, R.; Petreshock, J.; Rots, A.; Spitzbart, B.; Zografou, P.
Abstract: One of the requirements of the Chandra mission is to be able to quickly examine spacecraft data which span the full ten year planned mission lifetime. It was clear from the outset that warehoused FITS files would not meet this requirement. We opted to create a set of databases which resample all engineering telemetry into a fixed five minute time grid. This allows a year's worth of data to be compressed to the scale of about 10 GB. Bi-level data were written into special databases which only report when bi-levels change. This not only results in space savings, but allows for very rapid responses to queries which are concerned with system settings. Currently we can access one year's worth of data across several tables in under 15 minutes. We discuss the design of the databases, the status of testing and implementation. Finally, we discuss ongoing database development and plans for handling image and source data.
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