Positioned on the Mercury Transfer Module, the monitoring cameras caught BepiColombo’s structural elements, including its antennas and the magnetometer boom, as well as capturing the planet. In many of the images, it is possible to identify some large impact craters.
“The flyby was flawless from the spacecraft point of view, and it’s incredible to finally see our target planet,” said Elsa Montagnon, Spacecraft Operations Manager for the mission.
The closest approach took place at 7:34 p.m. at an altitude of 199 km from Mercury’s surface. Because the spacecraft arrived on the planet’s nightside, conditions were not ideal to take images directly at the closest approach, so it took the nearest images from 1,000 km.
Scientific data from a number of instruments along with the images were collected during the encounter and downloaded the next day.
“It was very exciting to see BepiColombo’s first images of Mercury, and to work out what we were seeing,” says David Rothery of the UK’s Open University who leads ESA’s Mercury Surface and Composition Working Group. “It has made me even more enthusiastic to study the top quality science data that we should get when we are in orbit around Mercury, because this is a planet that we really do not yet fully understand.”
BepiColombo is using the gravity from nine planetary flybys — one at Earth, two at Venus and six at Mercury — as well as its solar electric propulsion system to steer itself into Mercury’s orbit. Its next Mercury flyby will take place on 23 June, 2022, and its main science mission will begin in early 2026.
Although its cratered surface looks like Earth’s Moon at first sight, Mercury has a very different history, much of which is still unknown. BepiColombo will map the planet’s surface and analyse its composition to learn more about its formation and evolution. One theory is that it may have begun as a larger body that was then stripped of most of its rock by a giant impact. This left it with a relatively large iron core, where its magnetic field is generated, and only a thin rocky outer shell.
“In addition to the images we obtained from the monitoring cameras we also operated several science instruments on the Mercury Planetary Orbiter and Mercury Magnetospheric Orbiter,” added Johannes Benkhoff, ESA’s BepiColombo project scientist. “I’m really looking forward to seeing these results. It was a fantastic night shift with fabulous teamwork, and with many happy faces.”
ESA’s interplanetary missions typically end up at relatively cold parts of the solar system. Conversely, BepiColombo will be the agency’s first planetary probe to travel near the Sun. This makes the mission especially challenging, as the star’s intense brightness and enormous gravity makes it difficult to observe Mercury from a distance and settle the spacecraft into a stable orbit.
Unlike the Moon’s bright highlands, Mercury’s surface is almost completely dark, and it was formed by vast outpourings of lava billions of years ago. These lava flows bear the scars of craters formed by asteroids and comets crashing onto the surface at speeds of tens of kilometers per hour. The floors of some of the older and larger craters have been flooded by younger lava flows, and there are also more than a hundred sites where volcanic explosions have ruptured the surface from below.
BepiColombo will explore these themes further, building on the data collected by NASA’s Messenger mission. It will address questions such as:
What are the volatile substances that turn violently into gas to power the volcanic explosions?
How did Mercury retain these volatiles if most of its rock was stripped away?
How long did volcanic activity persist?
How quickly does Mercury’s magnetic field change?
“It was an incredible feeling seeing these almost-live pictures of Mercury,” said Valentina Galluzzi, co-investigator of BepiColombo’s SIMBIO-SYS imaging system that will be used once in Mercury orbit. “It really made me happy meeting the planet I have been studying since the very first years of my research career, and I am eager to work on new Mercury images in the future.”
Frank White has authored or coauthored numerous books on topics ranging from space exploration to climate change to artificial intelligence. His best-known work, The Overview Effect: Space Exploration and Human...
Micah helps people understand and participate in the global space economy, commercial space companies, entrepreneurial activity, finance, government budgets and programs, or space policy. In his role as President of...
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