How a mission is chosen
Every five years, ESA issues a call for proposals for new space missions. This defines the size, cost and quantity of missions required, as well as the noting the trends emerging from modern science that ESA would like to pursue.
Missions come in two types: ‘Cornerstones’ which are the bigger missions, and ‘Flexi’ missions, which are smaller. Usually such a call produces around 100 responses from industrial and academic groups. The submissions range from single page outlines to complete proposal documents.
ESA’s various scientific committees of experts sift then through the submissions. These include the Astronomy Working Group, the Solar System Working Group, the Fundamental Physics Working Group, the Space Science Advisory Committee and the Science Programme Committee. Also, ESTEC staff members take an initial look at the feasibility of the missions.
From this effort, three or four candidates for each mission slot are chosen to enter an assessment phase. An ESA study scientist and study manager are assigned to each proposal and a one-year feasibility study is undertaken. This is when they will identify any new technology that will be needed.
The conclusions of these studies are presented to ESA’s scientific committees and other scientists, in two meetings usually held at ESA headquarters in Paris. The committees then make choices about which missions should proceed to ‘Phase A’.
Phase A involves industrial partners and results in preliminary designs for the spacecraft. These are presented, again in Paris to the various committees, and a final decision on which proposal will be selected for each mission is made.
Sometimes specific circumstances and opportunities allow this lengthy process to be cut short; as in the case of Mars Express and Venus Express, when the re-use of spare flight equipment from previous missions made the new projects possible.
Towards the end of 2003, the ESA committees will begin a detailed study of which trends in space science will dominate the scientific landscape in the decade 2010–2020, so that a new call for mission proposals can be issued during the next couple of years.
Last update: 13 September 2004