In order to reach its destination , the satellite was accelerated with the gravity field of Venus .
Since Mercury is so close to the Sun it was too difficult to incorporate an orbit around Mercury in the route so Mariner 10 orbited the Sun .
In order to reach Mercury 's destination , the satellite was accelerated with the gravity field of Venus .
Since Mercury is so close to the Sun it was too difficult to incorporate an orbit around Mercury in the route so Mariner 10 orbited the Sun .