BepiColombo is scheduled to launch no earlier than Friday, 19 October, at 9:45 p.m.
But why does it have to endure a 7-year long journey until it starts the actual study?
Another major challenge for mission planners was ensuring the spacecraft could withstand the searing temperatures of more than 350C so close to the sun.
A complex series of fly-bys past the Earth, Venus, and Mercury will also help to reduce BepiColombo's velocity by 7km/s.
"Launching BepiColombo is a huge milestone for ESA (the European Space Agency) and JAXA, and there will be many great successes to come", ESA Director General Jan Woerner said in a statement.
"Studying Mercury is crucial to better understand the formation of our solar system, how Earth formed and evolved and where we are coming from", said Benkhoff. After arriving in late 2025, the spacecraft - built under the industrial leadership of Airbus - will examine the peculiarities of Mercury's internal structure and magnetic field generation, as well as how the planet interacts with the sun and solar wind.
With the journey totalling some 8.5 billion kilometres - the equivalent of travelling from the Earth to Neptune and back again - Bepi will actually travel 38 times the maximum distance between the Earth and Mercury.
"It is the first Mercury mission to send two science orbiters to make complementary measurements of the planet's dynamic environment at the same time". The tiniest planet in the solar system, Mercury is relatively unstudied and probably holds many mysteries.
The Mercury Planetary Orbiter will also come equipped with a radiator created to reflect heat from the spacecraft, keeping it functioning even when close to the sun.
"Following its departure from Earth, the spacecraft will travel nine billion kilometers (5.6 billion miles) in seven years, completing nine planetary flybys at a top speed of 60 kilometers per second, all in order to reach the least explored planet of the inner Solar System".
The other two cameras are placed on the other side of the module: one will look down the extended solar array of the MTM, the other towards the MPO, capturing glimpses of the medium-gain antenna once deployed and, later, of the magnetometer boom. The mission of BepiColombo is simple, to figure out Mercury's history.
Getting close to a small planet, especially which is this close to the Sun is the tricky part. Because of its its proximity to the sun, it's difficult to observe with ground telescopes and hard to reach via spacecraft.
The European Space Agency (ESA) first proposed a mission to explore Mercury in 1993.
To generate the 10,000 volts of electricity needed to power the ion engines, BepiColombo has a pair of giant solar panels spanning 30 metres that unfold after launch.
The trip inward doesn't actually begin until April 2020 when the BepiColombo spacecraft races past Earth, using the planet's gravity to bend the trajectory onto a course carrying the satellites toward Venus.
NASA'sMariner 10 did three flybys in 1974 and 1975, providing the first up-close images.
The last spacecraft to visit Mercury was NASA's Messenger probe, which ended its mission in 2015.