Mission controllers based in Darmstadt, Germany, would spend much of Saturday talking to the spacecraft, to confirm they were properly configured for the long cruise ahead.
BepiColombo will launch tonight at the earliest, using the gravity of Earth, Venus, and Mercury to assist its seven-year journey to the rocky planet.
Once on station, the spacecraft will have to endure blistering 660-degree temperatures at Mercury's average distance of 37 million miles from the sun. During that time, the spacecraft will make one flyby of Earth, two of Venus, and six of Mercury before finally reaching its destination.
It's the first time the European and Japanese space agencies (Esa and Jaxa) have set out for Mercury.
Scientists hope the mission will tell them more about how the solar system was made and give them a better idea about the potential for life on exoplanets, which are planets found orbiting other stars.
BepiColombo was named after the late Giuseppe "Bepi" Colombo, an Italian scientist and engineer who played a leading role in the 1974 Mariner 10 mission. This means that a day on Mercury lasts two years, or 176 Earth days. More than 30 years later, NASA launched Messenger, the first spacecraft to successfully orbit and map Mercury's surface. The MMO, designed by the European Space Agency (ESA), will be investigating the magnetospheric interactions between the planet and the solar wind that is ejected from the Sun.
The ESA-developed Bepi will operate in Mercury's inner orbit, and JAXA's Mio will be in the outer orbit to gather data that would reveal the internal structure of the planet, its surface and geological evolution. Some other mysterious features of the planet that BepiColombo could help us better understand include why it appears to have shrunk over time and how it generates its own magnetic field despite spinning very slowly on its axis.
While BepiColombo's main science camera is enshrouded for the trip to Mercury, the craft is equipped with three low-resolution monitoring cameras to provide additional visual confirmation that arrays and antennas have deployed correctly-images of each will be received by ESOC over the course of the weekend. Its cost is estimated at 1.85 billion dollars.
Even if BepiColombo only partially fulfills its objectives, the knowledge that researchers gained in designing and launching the spacecraft will be applied to future missions.
After launch, BepiColmbo must constantly brake, otherwise it will fly straight past the planet!
Mercury is the closest planet to the sun, but not the hottest. Because of its size and closeness to the Sun, the planet orbit the sun very fast, which makes it very hard for any spacecraft that wants to visit it. It also is the 121st Airbus-produced spacecraft lofted by Arianespace, which has a backlog of 22 additional satellites to orbit for this manufacturer on future flights.
Only two NASA spacecraft, Mariner 10 and Messenger, have visited Mercury before, with Messenger intentionally crashing into the planet in 2015.
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