BepiColombo is a Mercury exploration project jointly planned by Japan and the European Space Agency (ESA). The proximity of Mercury to the Sun makes it difficult to observe and hard to reach by space flight. Three passes by NASA’s Mariner 10 in 1974-75 have been the only exploration conducted so far. The mission was inspired by the late Italian astrophysicist Dr. Giuseppe "Bepi" Colombo, who suggested that a spacecraft could get close to Mercury several times by using a gravity-assist swing-by of Venus. Hence the name of the project, BepiColombo.
Mariner 10 revealed the presence of a magnetic field and magnetospheric activities in Mercury. BepiColombo will conduct comprehensive observations of Mercury’s magnetic field, magnetosphere, and both its surface and interior. That will help determine how much it has in common with other planets and what elements are unique to Mercury as well as the origin and evolution of terrestrial planets.
This project consists of two orbiters. Mercury Planetary Orbiter (MPO) will observe the surface and interior; Mercury Magnetospheric Orbiter (MMO) will observe the magnetic field and the magnetosphere. JAXA is responsible for MMO, as Japan excels in the study of magnetic fields and magnetospheres. ESA is responsible for the launcher, the interplanetary cruising engine, the placement of BepiColombo into Mercury’s orbit, and the development of MPO.
Two spacecraft will be launched by Soyuz-Fregat 2B rocket. MMO and MPO will be separated at the Mercury orbit, and observe Mercury for about 1 year under collaboration.
Vibration test of MMO Mechanical Model is conducted in JAXA Sagamihara Campus Flight Environment Test Building. 
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