Space ships begin to mercury – science.ORF.at

If all goes as planned, the Euro-Japanese spacecraft "BepiColombo" will be launched in space tonight. By 2025, the unmanned spaceship must reach its destination: Mercury, the smallest and least explored planet in the solar system.

Space probes can not open enough into the outer solar system: Mars receives visitors every two years from the Earth, and Jupiter and Saturn can not complain about the lack of interest of the earthlings. However, the space probes, which leave the Earth in the other direction, that is to say that fly in the internal solar system, are sown in a sparse manner.

This trend should now be reversed: "BepiColombo" is a joint mission of the European Space Agency ESA and its Japanese counterpart, the JAXA. Europe provides the mission with the Mercury Planetary Orbiter (DFO) and Japan with the Mercury Magnetospheric Orbiter Mio (MMO). At first, the two probes, the European planetary explorer and the Japanese magnetic field observer, are stacked on top of each other in the payload of a European Ariane 5 rocket. There are also an umbrella and a technical refueling module for the long journey.

"So we have almost four superimposed elements, like four big Lego bricks," says Johannes Benkhoff, a scientist with the BepiColombo project at the ESTEC Center for Space Research in Noordwijk, the Netherlands.

ESA video of the flight "BepiColombo" bound for Mercury:

Like a chicken on the grill

The sun visor is the highest stage, the forward most front of the four-part space probe "BepiColombo". Because the Japanese probe rests above the European and is therefore facing the sun, it must be protected right in front, like a chicken on a grill. "You have to turn it continuously so that it does not burn," says Benkhoff. "If you stop his own rotation, he will burn."

However, during the flight to Mercury, the Japanese probe can not be rotated because it is firmly connected to the other elements of the "BepiColombo" construction. "That's why we have the Sun Shield, which wraps the Japanese orbiter and protects it from the sun's heat," says the ESA project scientist.

Arrived at Mercury, the European and Japanese probes separate then go to work. "Mercury is the closest to the Sun of all planets," said Go Murakami of the Japanese space agency JAXA. "That's why it's directly exposed to solar winds." The Earth has a magnetic field that protects them from these electrically charged particles. Mercury also has a magnetic field. But it is much weaker.

"We want to know if its weak magnetic field also protects powerful solar winds," said the Japanese scientist. As in the case of the Earth, the magnetic field of a planet is generated by the iron in its nucleus, which rotates. It could be a kind of dynamo, at the bottom of Mercury, responsible for magnetic field lines.

Countdown to the journey to the messenger of the gods

Mercury, the Roman messenger of the gods, is the patron saint of those who are in a hurry: travelers and merchants, but also thieves. Thus, the planet Mercury quickly crosses the space: it is the fastest of the solar system, it turns around the sun in only 88 days. One year on this celestial body only lasts about three months.

Before the probe reaches Mercury, all eyes are on the spaceport of Kourou in French Guiana, from where the long journey to Mercury and during the flight checking one of Giuseppe Colombo's predictions.

The Italian astronomer had observed Mercury with telescopes during the last century. And he has calculated the orbits on which space probes can hit the planet. In the honor of the probe, "BepiColombo" now bears his name. If its calculations prove correct, the joint Euro-Japanese project will arrive in April 2026 at Mercury.

Guido Meyer, science.ORF.at

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