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BepiColombo probe swings by Earth on way to Mercury – the Solar System's must-visit coronavirus-free resort

Check out this plucky Euro-Japanese spacecraft and its seven-year trip to innermost planet

BepiColombo, the first European-Japanese spacecraft to hopefully orbit Mercury, has swung by Earth for its first gravitational assist maneuver in its seven-year journey to the innermost planet of our Solar System.

It passed by our home world on Friday, reaching a minimum distance of about 12,700 kilometers from the surface; you can see what it's like to dive into Earth's gravitational well here.

Only a lucky few with the right telescopes would have been able to spot the spacecraft hovering above our outer atmosphere at 0425 UTC from the southern hemisphere. Don’t worry too much if you weren’t one of them, though: BepiColombo’s cameras captured several shots as it flew closer to Earth. You can see our fragile little marble growing in size as the spacecraft approaches in this GIF (warning: 8MB).

“[The] eclipse phase was the most delicate part of the flyby, with the spacecraft passing through the shadow of our planet and not receiving any direct sunlight for the first time after launch,” said Elsa Montagnon, ESA's BepiColombo Spacecraft Operations Manager.

“It is always nerve-wracking to know a spacecraft’s solar panels are not bathed in sunlight. When we saw the solar cells had restarted to generate electrical current, we knew BepiColombo was finally out of Earth’s shadow and ready to proceed on its interplanetary journey.”

BepiColombo on the launchpad

It's Two Spacecraft, One Mission as BepiColombo gets ready to launch


While gravity assists typically speed up a spacecraft, BepiColombo swung by Earth in the opposite direction to the planet’s orbit around the Sun, causing it to slow down. However, the maneuver pointed the probe toward the inner Solar System. As such, BepiColombo is now making its way to Venus, and will perform two flybys there in October this year, and in August 2021, to finally arrive at Mercury by 2025.

The space probe consists of two craft and a transporter: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO), the latter also known as Mio, aided by the Mercury Transfer Module (MTM), which will nudge them into the right orbits.

When you're trying to spin a gizmo around a tiny planet next to the biggest gravity well in the Solar System, the orbital planning is non-trivial. Boffins have spent decades sorting out the equations to get the craft into orbit around Mercury, and then shifting the gang economically into useful positions.

BepiColombo was named after Giuseppe "Bepi" Colombo, an Italian scientist and mathematician who in 1970 proposed a route that allowed NASA's Mariner 10 spacecraft to make not just one flyby of Mercury but three. Colombo used gravitational slingshot calculations from the Soviet Luna 3 missions, ensuring the Mariner became the first spacecraft to exploit a planet's mass – Venus in this case – for a gravity assist.

BepiColombo is a joint mission between ESA and the Japanese Aerospace Exploration Agency. Scientists hope that BepiColombo will be able to answer the mystery of Mercury’s origins, whether it has any water, and why it has a magnetic field. You can check in with BepiColombo and see where it is during its journey here. ®

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