See presentation by B. Christophe, “Gravity Advanced Package, a fundamental physics experiment for Jupiter Ganymede Orbiter Mission”, at the recent Gravitation and Fundamental Physics in Space, the GPhyS “Kick-Off” Colloquium, Les Houches, 20 – 22 October, 2009, at External Linkhttp://gphys.obspm.fr/LesHouches2009/Program.html.