This view shows our Solar System from above with the Earth and Mars in opposition about the Sun, placing Mars and the Sun in to conjunction as seen from the Earth, on 5 December 2008. This image clearly illustrates the path that line-of-sight radio signals must travel - through the Sun's turbulant atmosphere - between Mars Express and the Earth.
Graphic generated by Mars Express mission controllers at ESOC, the European Space Operations Centre, using Celestia.