Proposal history

Following the great success of the SOHO mission, launched in December 1995, and the impressive step forward in the understanding of our nearby star allowed by the SOHO results, it was clear to the solar physics community that the next step in the exploration of the Sun was requiring a close approach to investigate in detail its atmosphere from the layers below the photosphere (accessible via helio-seismology) to the outer corona at all latitude, including the poles and to navigate the unexplored circumsolar regions.

1998 Recommendation to fly an observatory in orbit around the Sun, expressed by the solar and heliophysics community at the meeting “Crossroads for European Solar and Heliospheric physics” in Tenerife.
1999 The concept of an ESA Solar Orbiter was formulated in an ESA pre-assessment study.
2000 Solar Orbiter was proposed in the frame of the Horizon 2000+ ESA Scientific Program. Solar Orbiter proposers: E. Marsch, E. Antonucci, P. Boscheler, J.-L. Bougeret, R. Harrison, R. Schwenn, J.-C. Vial.
Selection of Solar Orbiter by the ESA Science Program Committee.
Delta Assessment Study: Solar Orbiter — a high-resolution mission to the Sun and inner heliosphere. Solar Orbiter Assessment Study Report, ESA-SCI(2000)6.
2004 ESA Science Program Committee confirms the selection of Solar Orbiter within the Horizon 2000+ Program.
2007‑2008 Proposal of the scientific instruments of the Solar Orbiter payload.
2008 Solar Orbiter is integrated in the new Cosmic Vision 2015-2025 ESA Program and has to re-compete.
2009 Announcement of the scientific instruments selection.
Issue of the Second Assessment Study Report: Solar Orbiter — Exploring the Sun-heliosphere connection. Solar Orbiter Assessment Study Report, ESA/SRE(2009)5.
2010 Selection of Solar Orbiter as a candidate for the first medium class mission, M1, of the Cosmic Vision Program.
2011 Selection of Solar Orbiter as the first element of Cosmic Vision 2015-2025.