... The Chandra Data Archive team at the Chandra X-ray Center has developed middle tier services that are used by both our search and retrieval applications to uniformly access our data repository. ... Programs can call the services to retrieve observation data such as a single FITS file, a proposal abstract or a detailed report of observation parameters. ... Given an observation ID, filetype and data-processing level, this service returns the content of a single file from the Data Archive. ...