Perched inside a protective nose cone atop the Ariane 5, ESA's Mercury Planetary Orbiter and JAXA's Mercury Magnetospheric Orbiter were poised for blastoff from the Guiana Space Center near Kourou, French Guiana, at 9:45 p.m. EDT (GMT-4; 10:45 p.m. local time).
Over the course of seven years, the spacecraft will trace a complex path with an Earth flyby in 2020, two Venus flybys and six Mercury flybys.
The first mission to Mercury has been launched on 19 October, and the European and Japanese space agencies are happy to announce that everything is going according to plan.
JAXA President Hiroshi Yamakawa, who earlier managed the project, said, "We have high expectations that the ensuing detailed observations of Mercury will help us better understand the environment of the planet, and ultimately, the origin of the Solar System including that of Earth".
They will tour Mercury for a year before feeding their findings back to earth.
Only two previous missions, carried out by NASA, have ever reached the planet.
Mercury is also the only rocky planet orbiting the Sun beside our own to have a magnetic field.
"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". Data collected from 16 scientific instruments will provide insights into the geological and chemical composition of the planet, along with its structure, the characteristics of its magnetic field and how it interacts with the solar wind.
If you haven't been up to date about the European and Japanese space agencies working together in a project called The BepiColombo Mission, then here's a short article about it on Great Lakes Ledger. Though current plans call for a single year of research, the spacecraft are created to operate in a research mode for two years, he said.
Enlarge / It is no easy task to put a spacecraft into orbit around Mercury.
Enlarge / Some of the main science themes for the BepiColombo mission.
BepiColombo is the 51st mission (and 73rd spacecraft) launched by Arianespace for ESA.
Scientists hope the £1.4 billion mission will unravel some of Mercury's mysteries, such as the reason for its oversized iron core, its spectacular volcanic vents, and tantalising hints of water ice in shadowy parts of the scorching hot planet.
The craft must constantly fight the Sun's gravitational pull to achieve orbital insertion around Mercury.
It's not exactly a quick trip to the closest planet to the sun.
Few spacecraft have visited Mercury because of the planet's proximity to the sun - less than 60 million kilometres (37.3 million miles) away compared with nearly Earth's 150 million kilometres - which makes any trip there challenging.