By going at night?!
I'll get me....
The European Space Agency hopes to blast into space a probe that will get closer to the Sun than any other craft has managed. solar_orbiter_esa Artist's impression of Solar Orbiter. Photo by European Space Agency The ESA said on Tuesday it aims to launch the Solar Orbiter from Cape Canaveral on a NASA-provided Atlas rocket …
I think that Arianne is a bit overkill for this, and it probably won't have a launch vector that can be easily shared (normally Arianne launches 2 large sats and possibly a few other bits in a single launch; except for ATV which is bloody heavy, and the new James Webb telescope).
There is an option to launch using a Soyez from Guianna instead, but the Soyez is a bit tight on the launch mass with not much margin.
Maybe they could've scaled SOLO up a bit and included more instruments, but that would've upped the cost, and ESA is not exactly rolling around with money.