Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. XTCE (for XML Telemetric and Command Exchange) is an XML based exchange format for spacecraft telemetry and command meta-data. Using XTCE the format and content of a space systems command and telemetry links can be readily exchanged between spacecraft operators and manufacturers. XTCE was originally standardized by the OMG. In April 2007 the OMG released revision 1.1 of XTCE as an OMG available specification. Version 1.0 of the XTCE specification is a CCSDS red-book specification and version 1.1 is a candidate CCSDS blue-book specification.