Rosetta in the year of the swing-bys

The International Rosetta Mission, a cornerstone mission of the European Space Agency Scientific Programme, was launched on 2nd March 2004 on its 10 years journey towards a rendezvous with comet Churyumov–Gerasimenko. Once reached the comet nucleus in summer 2014, Rosetta will orbit it for about 1.5 years down to distances of a few kilometres and deliver a Lander, named Philae, onto its surface. In the long cruise to its target, Rosetta performs four gravity assist manoeuvres, three times with Earth and once with Mars. After the first successful Earth swing-by in March 2005, the year 2007 started with a highly critical Mars swing-by, carried out in February at a target altitude over the planet's surface of only 250 km. This manoeuvre re-oriented the spacecraft trajectory towards the second Earth swing-by, planned for November 2007. During both swing-by phases the payload was operated to achieve a variety of scientific and calibration objectives. This paper continues the periodic reporting of the operational experience from the Rosetta mission operations. Preparation and execution of the swing-by activities are described. As derived from the lessons learned in this phase, a generic approach to be adopted for planning and execution of planets swing-by phases, including those of future missions like BepiColombo, is presented.