The Mars Sample Return (MSR) program is an international challenge aimed at analyzing on Earth samples collected on Mars surface, in order to permit scientists to gain various orders of magnitude on the accuracy of their measurements. The last baseline of MSR is a campaign of three different missions (Caching mission, Lander and Orbiter), collaborating for collecting the samples, caching them in an Orbiting Sample (OS), capturing it once injected into Martian orbit by a Mars Ascent Vehicle (MAV), and taking it back to Earth. At the end of February 2012, the MSRO phase A, a study focused at providing a preliminary design of the Orbiter, concluded satisfactorily. Thanks to its consolidated experience in rendezvous and docking gained with previous activities such as HARVD (High Integrity Control System for Rendezvous and Docking), GMV has made a worthy contribution to the Orbiter mission architecture, designing the rendezvous and capture phase (orbits, approach manoeuvres, attitude profiles, relative sensors, navigation filters, etc.). The promising study conclusions will be forwarded by ESA to the Ministerial Council that, at the end of this year, will make a decision about the future of the MSR mission.