The taste of Mercury… This is not intoxication, but a beautiful astrological note that BepiColombo promises us this weekend. The space probe flew over the first planet in the solar system on Saturday morning (1:34 am in Paris), just 200 kilometers above sea level. A quick paragraph, enough time to gather a batch of photos and scientific data that she will now pass on to her parents: the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (Jaxa).

Why go in a gust of wind? Because getting close to Mercury is a complex maneuver that requires it to be repeated several times before it eventually puts itself into orbit around the small planet next to the Sun. “Going to Mercury is more difficult than going to Jupiter, because of the attraction of the sun. Mercury is a small planet with a low mass. When you reach the bottom of the balloons, you will fall into the sun,” Kader Amsif and Pierre Bousquet, the French mission directors, explained to us in 2018, when Pepe Colombo took off. We must then send the ship on a wonderful journey around the sun by screwing up the ellipses little by little, like marbles on the walls of the funnel.

Surveillance Cameras

During this spiral-shaped journey, BepiColombo crossed Earth again in April 2020, and then pasted Venus twice, in October 2020 and in August. All of these flybys represent opportunities to take advantage of the planet’s “gravity assist”: using their gravity, the space probe is gaining momentum, bending its trajectory toward the center of the solar system and gradually settling on Earth. The orbit of Mercury around the sun. With this first flight, BepiColombo gained 2.1 km/s (speed relative to the Sun). The probe will still flirt with Mercury five times by 2025 before it “stops” there, that is, it goes into orbit around the planet.

Since we know so little about Mercury, this first flight is a valuable opportunity to begin studying the planet before the final arrival of BepiColombo in December 2025. Unfortunately, the probe will not be able to use its high-resolution camera because it is currently hidden under the transfer module that provides thrust to Mercury. But BepiColombo was able to rely on three other black and white surveillance cameras, the “MCAM,” to attack Mercury five minutes before flyby and up to four hours afterward, Explain ESA.

The surface is studded with potholes

At time T, which is closest to the planet, BepiColombo will have passed exactly 198 kilometers from its surface. But on Mercury’s face after that, it was dark… which is why the closest photo will only be taken at a distance of 1,000 kilometers. We must be able to determine “High Impact Drilling”, The European Space Agency predicts, that the surface of Mercury is riddled with craters like the Moon.

The probe and the planet are now located more than 100 million kilometers from Earth – a known location 500 meters away “Thanks to the superb accuracy of our network of ground stations and antennas spread all over the world, and the continued efforts of our navigation team,” Frank Budnik, responsible for the mission’s flight dynamics, confirms. The data takes about six minutes to reach the terrestrial antennas at the speed of light. The bandwidth is not so much in space, the images have to be transmitted every Saturday morning, image by image.