A spacecraft bound for Mercury has swooped past the Earth in a maneuver to tweak its path to the solar system's innermost planet. Scientists hope it will slow the probe down, to ensure it doesn't overshoot the target.
A ground team at the European Space Agency's operations center (ESOC) in Darmstadt, Germany — reduced in number amid the coronavirus lockdown — monitored the operation.
Before leaving Earth's vicinity, BepiColombo beamed back black-and-white pictures of home.
The team sought to fine-tune the spacecraft's trajectory and speed, ensuring it doesn't overshoot the scorched planet, which lies just 60 million kilometers (37 million miles) from the sun.
The tug of gravity from Earth slowed the spacecraft down and fixed it more firmly on its path to the sun. It is the first of nine planet-based gravity assists aimed at guiding BepiColombo to its intended destination in one piece.
"Without these maneuvers, it would simply fly past Mercury," said ESOC head Paolo Ferri. "It has to brake."
The closest part of the approach — with the spacecraft some 12,700 kilometers away from Earth — occurred over the South Atlantic. Telescopes in Chile even caught a glimpse of the speeding probe.
One critical phase came soon after that as the probe flew into the earth's shadow, shielded from the sun for 34 minutes and being forced to rely on its batteries.
The mission is a joint project of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA).
The COVID-19 pandemic threat forced the team to work with minimal face-to-face interaction while ensuring all steps in the process were properly covered.
The spacecraft is carrying two scientific orbiters, and it should reach Mercury in 2025. It will swing past Venus twice — firstly in October — and six times past Mercury itself.
Scientists hope to learn more about the origin and composition of Mercury, the least explored of our solar system's four rocky planets. The planet is only a little bigger than our moon and circles the sun in just 88 days.
The probe is named after Italian mathematician and engineer Giuseppe ''Bepi'' Colombo, who devised the use of planetary flybys for approaches to Mercury. He died in 1984.
BepiColombo spacecraft launches quest to survey Mercury
Humans still know very little about Mercury, the planet closest to the Sun. It's hoped the BepiColombo space probe will reveal the planet's secrets. Here is what we do already know about Mercury.
Image: DLR/ESA
Meet the BepiColombo space probe
The BepiColombo spacecraft is scheduled to start its journey on October 20, 2018. It is a joint project of the European Space Agency (ESA) and the Japanese Space Agency (JAXA). BepiColombo consists of two satellites — the European Mercury Planetary Orbiter (MPO) and the Japanese Mercury Magnetospheric Orbiter (MMO). They will explore Mercury on different orbits starting in early 2026.
Image: DLR/ESA
Unknown beauty
To date, only two space probes have come close to Mercury. The last one was the successful NASA probe, Messenger. It orbited the planet more than 4,000 times and sent over 250,000 images back to Earth. A planned crash landing in 2015 due to lack of fuel saw the end of the Messenger mission.
Image: picture-alliance/dpa
Long nights
Mercury probes must be able to withstand a lot. Above all, the extreme temperature differences pose great challenges to engineers and manufacturers here on Earth. Mercury is uninhabitable for another reason — the sun rises there once every 176 Earth days. Yes, you read correctly.
Image: picture-alliance/dpa
Hot, hot, hot — but no atmosphere
On Mercury it is hot, but not it's as bad as one would expect from a planet so close to the Sun. Its neighbor, Venus, experiences much hotter conditions. The reason: Mercury, in contrast to Venus, has no atmosphere and heat leaves the planet in the form of radiation. Temperatures vary from 430 degrees Celsius (806 degrees Fahrenheit) to minus 180 C.
Image: Reuters/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Unstable and eccentric
Mercury is the smallest planet in our solar system and is closest to the Sun. Its orbit around the Sun is unstable, and is growing larger all the time because Jupiter is slowly pulling Mercury out of its orbit. At some point, this could see Mercury colliding with Earth. But fear not, that won't happen for many millions of years.
Image: Getty Images/AFP/IAU
Similarities to the moon
The surface of Mercury is scarred and filled with craters like those on our moon. Many meteorites and asteroids have violently smashed into the planet in the past. Some craters are several hundred kilometers in diameter.
