Mercury-bound spacecraft whizzes past the smallest planet for | Astro Wonders

Mercury-bound spacecraft whizzes past the smallest planet for the 2nd time

The Mercury-bound probe BepiColombo has taken its second look at its target planet today during a superclose flyby designed to slow the spacecraft down and adjust its trajectory.

BepiColombo is a joint mission by the European Space Agency and the Japan Aerospace Exploration Agency. The mission, consisting of two orbiters that travel to Mercury stacked on top of each other, launched into orbit around the sun in 2018. Since then, ground controllers have been adjusting the spacecraft's trajectory through a series of nine flyby maneuvers to gradually slow BepiColombo down so that it can enter orbit around the solar system's innermost planet in 2025.

The June 23 flyby was BepiColombo's second at Mercury, following the probe's first encounter with the planet in October 2021. The probe made its closest approach to Mercury's surface at 0944 GMT, when it passed only 200 kilometers from Mercury's crater-riddled surface, closer than the two orbiters will operate once the mission begins in earnest.

The probe was taking images of the scorched planet during the flyby with its low-resolution monitoring cameras that are mounted on the spacecraft's transfer module. ESA released the first image about four hours after the closest approach, revealing large impact craters including a 120-mile-wide basin.

The two orbiters together carry 16 scientific instruments, but only about 60% of those were operational during the 48 hours around the closest approach, ESA's BepiColombo project scientist Johannes Benkhoff told. The rest, including high-resolution cameras, cannot be operated in the cruise configuration, as they are hidden either by the spacecraft's transfer module or its sunshield.

Benkhoff said the spacecraft's magnetometers and particle detectors were switched on during the flyby and will likely generate valuable scientific data about the solar wind in Mercury's vicinity.

During this flyby, BepiColombo approached Mercury from the night side, Benkhoff noted, which meant that imaging could only start 4 minutes after the closest approach, when the planet was sufficiently illuminated. By then, the probe was about 800 km away from Mercury's surface.

The images, which ESA plans to release within about a day, are expected to reveal craters and tectonic faults on Mercury's sunburnt surface.
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