Solar Orbiter spacecraft Venus flyby, illustration. Solar Orbiter (SolO) is a spacecraft under development by the European Space Agency (ESA). It is planned for launch in February 2020, and will reach the Sun via numerous gravity assist flybys of Venus (and one of Earth). At its closest approach in its orbit, it will be around 42 million kilometres from the Sun. The instruments it will carry include the Solar Wind Analyser, the Polarimetric and Helioseismic Imager, and the Radio and Plasma Wave analyser. Solar Orbiter will study the heliosphere, the bubble created in space by the solar wind. It will be the first satellite to provide close-up views of the Sun's polar regions. It will also attain high speeds, nearly matching the Sun's axial rotation.