The Fourth Solar Orbiter workshop is organized around sessions addressing the mission's main scientific objectives and the synergy with Solar Probe Plus and other space- and ground-based observations. Solar Orbiter is one of the key missions in our quest to understand how the Sun creates and controls the heliosphere.
Recent scientific findings relevant to these objectives are solicited, particularly those that exploit linkages between remote sensing and in situ observations. Solar Orbiter is competing for the first M-class launch slot in ESA's Cosmic Vision Programme. If confirmed in June 2011, it is scheduled for a January 2017 launch, and its operational orbit will have a minimum perihelion distance of 0.28 A.U. By the end of its nominal seven-year mission, it will achieve +/- 25 degrees heliolatitude and, after an additional three years of extended mission, +/-34 degrees.