The Chandra X-ray Center Data System (CXCDS) software provides the end-to-end software support for Chandra mission operations. The CXCDS Software Team develops, maintains, and supports the software that drive the CXC-based forward (proposer to spacecraft) and return (spacecraft to observer) threads necessary to perform the Chandra observing program. The Data System also includes the CIAO data analysis package and the Chandra Source Catalog (CSC) processing system that recently completed CSC 2.1. The software system consists of ~2 million logical lines of code, including C/C++, Python, SQL, Java, Perl, and a few stray algorithms written in Fortran. The Chandra Data Archive manages the operational threads and serves all data of the system. The data products are written in FITS format and are OGIP and IVOA compliant.
For twenty five years the CXCDS has served Chandra science operations and the user community well. The up-front planning and detailed design, conceived in the mid-1990’s and implemented for the operational system by launch in 1999, has paid off. The Software Team has managed operational changes to algorithms and processing, operating systems, compilers, scripting languages, and most recently a configuration management system migration to Git. All of these upgrades and many more have been possible given the structured architectural design that enabled, among other things, modularity and flexibility to manage change.
In this talk, I’ll provide insight on the longevity of the Chandra Data system, our ability to introduce change successfully, and what a new project can take away from our experience going forward.