Efficient Development of the Herschel-Planck Mission Data Systems

The European Space Agency’s Space Operations Centre (ESOC), in Darmstadt, Germany, has been involved in the development of operational spacecraft simulators and mission control systems (MCS) for ESA projects over the past 35 years. Together, these form the Mission Data Systems (MDS) for each project. This paper presents the Mission Data Systems for the Herschel-Planck project, which is part of ESA’s Astronomical Mission Family. The Herschel and Planck spacecraft are planned to be launched together by Ariane 5 in 2007 and will both be in Lissajous orbits around the L2 point, approximately 1.5 million km from Earth in the anti-sun direction. Herschel is an observatory mission and Planck is a survey mission. At ESOC the two spacecraft will have a common Flight Control Team and the same Mission Data Systems. The Herschel-Planck missions represent a major step forward in terms of technology and technological demands. The spacecraft and instruments are designed for autonomous operations driven by an on-board schedule, relying on a single 3-hour telecommunication period per day. Huge amounts of data will be stored on-board and downlinked at data rates (1.5 Mbps) that are unprecedented for such missions. The short contact window and high data rates impose very high performance demands on the Mission Data Systems. In particular, there are very high monitoring and archiving requirements on the mission control system. Furthermore, emulation of the on-board processors (2 per spacecraft) is extremely demanding and is the main driver of the simulator design and platform selection. The large amount of on-board storage also impacts the simulator resources and performance. The Herschel mission has a planned lifetime of 3.5 years and Planck 2 years. This results in maintainability requirements for the Mission Data Systems from 2004, start of the development, until at least 2010. The paper discusses in detail the challenges related to the above and the solutions that have been identified. Herschel and Planck are also the first ESA missions to adopt the promising concept of a “Smooth Transition”, involving both space and ground segment development, which can be summarized as “Reuse and share rather then redevelop”. This paper describes ESOC’s contribution to the implementation of this concept, the benefits this brings to the project and to the Mission Data Systems developments in particular. The following areas are covered: —The enlargement of the Spacecraft Control and Operations System (SCOS-2000) infrastructure user community: more specifically the adoption of SCOS-2000 across the Project as the central control and monitoring element of the various Electrical Ground Support Equipments and the use by the scientific community of the On-Board Software Maintenance System (OBSM) developed as part of the mission control system; —Mission Data Systems commonality between the two missions and reuse from predecessor data systems and space segment SCOS-2000-based developments. The Herschel-Planck project is a further step in the continuous improvement of the Mission Data Systems (MDS) development process at ESOC. The paper describes a new development strategy that emphasises the importance of efficient and effective validation in a world of scarce resources and less and less time to develop systems that are more and more complex. The approach adopted by the Herschel-Planck team maximises the usage of MDS infrastructure test tools for mission control system and simulator validation and introduces system automated testing based on new tools. It also adopts solutions aimed at alleviating the dependence of the simulator development on external inputs during the different stages of its development.