The Science Programme of the European Space Agency is a long-term programme of space science and space exploration missions. Managed by the agency's Directorate of Science, The programme funds the development, launch, and operation of missions led by European space agencies and institutions through generational campaigns. Horizon 2000, the programme's first campaign, facilitated the development of eight missions between 1985 and 1995 including four "cornerstone missions" – SOHO and Cluster II, XMM-Newton, Rosetta, and Herschel. Horizon 2000 Plus, the programme's second campaign, facilitated the development of Gaia, LISA Pathfinder, and BepiColombo between 1995 and 2005. The programme's current campaign since 2005, Cosmic Vision, has so far funded the development of ten missions including three flagship missions, JUICE, Athena, and LISA. The programme's upcoming fourth campaign, Voyage 2050, is currently being drafted. Collaboration with agencies and institutions outside of Europe occasionally occur in the Science Programme, including a collaboration with NASA on Cassini–Huygens and the CNSA on SMILE.
Governance
The Science Programme is managed by the European Space Agency (ESA)'s Directorate of Science, and its goals include the proliferation of Europe's scientific presence in space, fostering technological innovation, and maintaining European space infrastructure such as launch services and spacecraft operations. It is one of ESA's mandatory programmes in which each member state of ESA must participate. Members contribute an amount proportional to their net national product to ensure the long-term financial security of the programme and its missions. The programme's planning structure is a "bottom up" process that allows the European scientific community to control the direction of the programme through advisory bodies. These bodies make recommendations on the programme to the Director General and the Director of Science, and their recommendations are independently reported to ESA's Science Programme Committee (SPC) – the authority over the programme as a whole. The programme's current advisory structure consists the Astronomy Working Group (AWG) and the Solar System and Exploration Working Group (SSEWG), who report to the senior Space Science Advisory Committee (SSAC) that reports to the agency's directors. Membership on the advisory bodies last three years, and the chairs of the AWG and SSEWG are also members of the SSAC. Ad hoc advisory groups may also be created to advise on certain mission proposals or the formulation of planning cycles.
Missions in the programme are selected through competitions in which members of the European scientific community submit proposals to ESA. During each competition, the agency outlines one of four mission categories for which proposals need to meet the criteria of. These are the "L"-class large missions, the "M"-class medium missions, the "S"-class small missions, and the "F"-class fast missions, each with differing budget caps and implementation timelines. The proposals are then reviewed by the AWG, SSEWG, engineers at ESA, and any relevant ad hoc working groups, as part of a feasibility study known as "Phase 0". Missions which require new technologies to be developed are reviewed during these studies at the Concurrent Design Facility at the European Space Research and Technology Centre. After the study, up to three proposals are selected as finalists in "Phase A", in which a preliminary design for each candidate mission is formulated. The SPC then makes a final decision on which proposal proceeds to phases "B" through "F", which include the development, construction, launch, and disposal of the spacecraft used in the mission. During Phase A, each candidate mission is assigned two competing contractors to build their spacecraft, and the contractor for the winning mission is chosen during Phase B.