Cryosat-2: Impact of Mission Resuscitation on Data System

Abstract

In October 2005, a launcher failure ended the CryoSat mission before that a single bit could be processed by the Ground Segment. Since the future of the mission was not known a formal close-down of the activities, including the documentation and all systems was performed, ensuring consolidation of pending issues and configuration control of all the available systems. The overwhelming interest from the science community supported the idea to rebuild the satellite, now called CryoSat-2, to fulfill the mission with exactly the same objectives, and to be in orbit as soon as possible. With the assumption that all of the systems would be the same, the estimated costs for the new mission assumed also the maximum reuse. In spite of the good intentions, a number of changes were enforced dictated by different drivers either on the ground or space segment. The paper will describe how the mission redevelopment could be achieved within the estimated budget, even including the unavoidable changes. Although the mission operations would theoretically be the same, at least 80% of the team changed since the launch failure, requiring therefore a high level of training. A complete test validation campaign had to be executed, as if it was a new mission, from unit level right up to the end-to-end system tests. Some further details will be given about the impact of the differences on the already available systems and it will explain the strategy adopted to avoid unreasonable increase in costs. The flexibility of ESOC with respect to the people and mission data systems will be emphasized as a key factor in this situation. The paper will conclude describing how the motivation and strong commitment of a few key personnel made it possible to resuscitate the mission at such a minimal cost and also mentioning whether any of the methodologies could be applied to the lifecycle of a nominal mission.