The BepiColombo Mercury Transfer Module and Mercury Planetary Orbiter being prepared for chemical propulsion fueling.
The transfer module will use both ion propulsion and chemical propulsion, in combination with gravity assist flybys at Earth, Venus and Mercury to bring the two science orbiters close enough to Mercury to be gravitationally captured into its orbit. There, ESA’s Mercury Planetary Orbiter will use its small thrusters to deliver JAXA’s Mercury Magnetospheric Orbiter into its elliptical orbit around Mercury, before separating and descending to its own orbit closer to the planet.