1. The Solar Orbiter mission Solar Orbiter represents a new approach to solar studies. –A huge increase in discovery space The payload consists of a suite of 8 in-situ instruments and 5 remote sensing instruments (EUV Imager, EUV spectrometer, Visible-light imager/ magnetograph, coronagraph and radiometer) Orbit schematic 0.5 1.0

3. Slow and fast solar wind

4. The solar cycle variation of the solar wind

5. The engineering challenge Solar Orbiter is a specially designed three-axis stabilised spacecraft. It is designed to always point its smallest face to the Sun so the spacecraft is protected by a sunshield. At closest approach to the Sun, Solar Orbiter will receive 25 times the radiation per square metre that the Earth does. The spacecraft will also be kept cool by the positioning of special 'radiators', which will dissipate excess heat into space.

6. An Imager for Solar Orbiter The Solar Orbiter mission is a key mission for solar system science. Fundamental physical processes (waves/magnetic reconnection/dynamo) Linking the Sun and the inner heliosphere Exploring the solar atmosphere out of the ecliptic (slow and fast solar wind)

7. Fundamental physical processes We can, with excellent seeing, resolve 70 km in the photosphere with a ground- based telescope. SO will allow us to do better than this even in the corona! (and more than an order of magnitude better than currently possible e.g. TRACE 750km). At this resolution we will be able to observe MHD waves and reconnection at the fundamental physical scales. Rutten et al., 2003 G-bandCa II Cattaneo, Emonet and Weiss, 2003 3-D modelling showing the interaction between magnetic field and convection

8. Observing up close… This resolution will allow us to observe magnetic loops at their fundamental size. The smaller the scale, the more (rapid) activity we observe (TRACE observes with time resolution of seconds). Factor of 5 Factor of ~100

9. Linking up with in situ…

10. Current Status The current schedule is for the AO to be released in 2007 (ish). Call for Letters of Intent to Propose for the Solar Orbiter payload in advance of the formal AO (this summer!). The launch date is now most likely 2017 - with 4.5 yrs to get into orbit. We have been working here on technology development for the mission for several years - this will continue!