An Interface Specification for Requesting Space Link Extension Services from NASA TT&C Networks

Abstract

The Consultative Committee for Space Data Systems (CCSDS) has produced Recommendations (specifications) for several Space Link Extension (SLE) transfer services for the standardized, interoperable exchange of spacecraft telemetry and command data between a spaceflight mission’s ground facilities and the tracking, telemetry, and command (TT&C) networks that are used to communicate with the mission’s spacecraft. The European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) Deep Space Network (DSN) have implemented these SLE transfer services. Other space agencies are prototyping SLE services, several spaceflight missions have already adopted SLE, and JPL has adopted SLE as the standard interface between mission facilities and the DSN for the foreseeable future. NASA’s Space Network (SN) and Ground Network (GN), as well as other national space agencies, are evaluating the adoption of SLE services as their standard for future mission support. The type, number, and operational characteristics of the SLE services can vary from mission to mission, resulting in the need for management interaction between the mission and the supporting TT&C network. This management interaction nominally includes: Pre-flight agreement(s) between the mission and the TT&C network that specify the limits on types, numbers, and operational characteristics of the SLE services to be provided over the mission lifetime Requests for service on a per-pass basis. Such requests may contain values for SLE service parameters if those parameters have not been fixed for the lifetime of the mission in the pre-flight agreements Requests to modify the values of certain SLE service parameters during the pass Transfers of SLE service status information Responses to the various requests (e.g., confirmation of the original request, return of requested information, etc.) Notifications (e.g., change in status of ability to support service) As a companion activity to the specification of the SLE transfer services, CCSDS has developed a detailed framework for a management interface through which a mission may request SLE services and modify and monitor their execution. This CCSDS SLE service management (SM) framework is abstract and not intended to be implemented directly. Rather, it is intended to be mapped into one more concrete specifications based on specific (management) information interchange technologies. NASA has begun to apply and adapt the CCSDS SLE service management framework to a concrete specification written in the eXtensible Markup Language (XML). XML is emerging as the premier standard for automated information exchange, and its use in this specification will enable the automation of service request exchanges using XML-based tools and technology. The objective of this activity is to produce a specification that addresses not only the specific needs of NASA’s DSN, GN, and SN, but also