European Space Agency Science Programme
[12][13] Members contribute an amount proportional to their net national product to ensure the long-term financial security of the programme and its missions.
[8][9][19] Ad hoc advisory groups may also be created to advise on certain mission proposals or the formulation of planning cycles.
[10] Missions in the programme are selected through competitions in which members of the European scientific community submit proposals to ESA.
[5][21] 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".
[23][25] 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.
[29][30][31] In 1970, the governing Launch Programme Advisory Committee (LPAC) of ESRO made a decision not to execute astronomy or planetary missions, which were perceived as beyond the budget and capabilities of the organisation at the time.
[38][39] The leadership and advisory structure of ESA's Directorate of Science changed immediately prior to the programme's establishment.
In November and December 1983, ESA made the first open call for mission proposals to the European scientific community, based on an idea for a community-driven programme presented by Bonnet to the SPC in late 1983.
[59][60][61] Cornerstone objectives that were not selected due to financial and technical shortcomings, but mentioned by the survey committee as possibilities beyond Horizon 2000, included a solar probe, a Mars rover, and a two-dimensional interferometry mission.
[62] The survey committee's final meeting was held on San Giorgio Maggiore, Venice in June 1984, where the "Horizon 2000" plan was presented to ESA's then-Director General Erik Quistgaard, and leading members of the European scientific community.
[65] At the meeting, an additional fourth cornerstone presented by the SSWG was adopted – the Solar-Terrestrial Science Programme (STSP) consisting the Solar and Heliospheric Observatory and Cluster proposals, which became the first missions to be selected for launch under Horizon 2000.
[66][67] Quistgaard presented the Horizon 2000 plan at the 1985 Ministerial Council in Rome, where it was approved with only a 5% annual increase of the budget through to 1989, instead of the requested 7% through to 1991.
[69] However, an extension of the 5% annual increase through to 1994 was approved at the 1990 Ministerial Council in The Hague, which allowed all Horizon 2000 missions to be fully funded.
[75][77] By 1986, the cost of the STSP cornerstone was forecast to exceed its allocated 400 MAU budget,[78][79] and in a February 1986 meeting, the SPC was presented with the possibility of cancelling the cornerstone in favour of a medium-size mission selection between SOHO, Cluster, and the Kepler Mars orbiter proposal,[78][80] which had gained popularity among members of the SSAC.
[82] Despite this, the SSWG, SSAC, and SPC reaffirmed a commitment to the STSP cornerstone by descoping SOHO and limiting Cluster to three spacecraft,[83][84] and reaching a collaboration agreement with NASA in October 1986 that would reduce the mission's cost – they would provide testing, launch services, and operations of SOHO and contribute various scientific instruments,[85][86] while cancelling their Equator mission in favour of a fourth Cluster spacecraft on which American scientific instruments would be flown.
[90][91][92] The European-Soviet Vesta multiple-flyby minor planet mission and GRASP gamma-ray observatory competed,[93][94] but were rejected by the AWG and SSWG.
[92][95] After budget cuts resulting from the Challenger disaster forced NASA to retract its support for LYMAN and QUASAT,[96] the Titan Probe was selected by the SPC in November 1988,[92] and renamed Huygens in honor of Christiaan Huygens, who discovered Titan in 1655, per the suggestion of Swiss astronomers at the meeting.
The initial call of ideas and concepts was launched in 2004 with a subsequent workshop held in Paris to define more fully the themes of the Cosmic Vision under the broader subjects of astronomy and astrophysics, Solar System exploration and fundamental physics.
Large class (L-class) missions were originally intended to be carried out in collaboration with other partners with an ESA-specific cost not exceeding 900 million euros.
[124] ARIEL, a space observatory which will observe transits of nearby exoplanets to determine their chemical composition and physical conditions,[124] was ultimately selected on 20 March 2018.
[134] At the ESA Science Programme Committee (SPC) Workshop on 16 May 2018, the creation of a series of special opportunity Fast class (F-class) missions was proposed.
[140] ESA missions of opportunity include contributions to Hinode, IRIS, MICROSCOPE, PROBA-3, XRISM, ExoMars, Einstein Probe, and MMX.
