The ECSS Packet Utilization Standard and Its Support Tool

Abstract

In May 1994, the Committee for Operations and EGSE Standards (COES) of the European Space Agency (ESA) issued the Packet Utilisation Standard (PUS) in the ESA internal PSS standards system. The intention was to promote standardization and the re-use of on-board and ground systems by defining a standard application-level interface between space and ground. Since that date, two major developments have occurred that are relevant to the PUS: The PUS has been used, to varying degrees, by a large number of missions and is currently being adopted by virtually all future ESA missions. The European Cooperation for Space Standardization (ECSS) was established with the mandate for production of space-related standards and the PUS has been thoroughly reviewed and improved by the ECSS Working Group for “Ground Systems and Operations”. It will be published soon in the E-70 branch of ECSS. The PUS revision has been completed and this paper presents the improvements and extensions introduced in the new PUS (ECSS-E-70-41). In addition, tools aimed at easing the work of users of the ECSS PUS are being developed and are presented in this paper. INTRODUCTION The Consultative Committee for Space Standardization (CCSDS) recommendations for packet telemetry and packet telecommand [1-5], as well as the derived ESA Standards [6, 7] address the endto-end transport of telemetry and telecommand data between user applications on the ground and Application Processes on-board. In the early 1990s, there was a strong motivation within ESA to take this standardization process a step further by defining the application-level interface between ground and space in order to meet the operational requirements arising from the satellite check-out and mission operations domains. To this end, the PUS was prepared and was issued as an ESA PSS standard in May 1994 [8]. The PUS defines a set of “standard” packet-based Services by prescribing the service model (i.e. how the onboard Application Process should behave) and the structures of the associated telemetry and telecommand packets. Missions can choose to implement those standard PUS services that suit their particular characteristics and requirements. Moreover, a given service can generally be implemented at a number of different levels of complexity, from which a mission can choose. The PUS also