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Thoughts from the staff of the UCL Centre for Systems Engineering


Mission engineering for Sentinel 1

By Ian Raper, on 31 March 2014

This week will see the launch of Sentinel 1, a radar imaging satellite designed to deliver land and ocean monitoring services. If you would like to know more about the mission you can find that on ESA’s mission page https://earth.esa.int/web/guest/missions/esa-future-missions/sentinel-1

Before joining UCL I worked in the Earth Observation, Navigation and Science division of Astrium and I was heavily involved in the mission and systems engineering of Sentinel 1 in what is known as the Phase A-B1 studies. In ESA parlance Phase A is when the feasibility of a mission is studied. This primarily involves finalising the statement of need and proposing candidate solutions to meet the needs. Phase B is then the stage of coming up with a preliminary definition of the mission checking that the proposed solution will be able to meet technical requirements and that this can be done within schedule and budget. Phase B1 specifically delivers the system requirements that can be carried forward in the project.

One of the most important activities within these stages was the development of the Mission Operations Concept. This involves thinking through all of the periods of operation, so that is launch and early operations, nominal operations, non-nominal operations and eventually disposal. Thinking about how the mission is expected to operate in each of the periods really helps to define the mission architecture, i.e. the way the spacecraft, the launcher and all of the systems on ground that communicate with the spacecraft work together, and then helps ensure all the necessary requirements to enable the operations are captured.

The operations concept also proves to be a very useful communication tool between the many stakeholders involved in the project including the various technical experts from the customer, the industrial space segment team and the industrial ground segment team. By talking about how it is envisaged to operate the mission the various different viewpoints (e.g. the best way to do it from a spacecraft point of view and the best way to do it from a ground segment point of view) can be discussed and traded-off eventually leading to a decision that should work for everyone and delivers the mission objectives.

So for me the operations concept document is one of the most important systems engineering products and should be started at the earliest possible opportunity in a complex system project. It aids architectural definition and requirements capture but perhaps most importantly it facilitates better communication amongst the people designing and developing the system which should lead to a better outcome.