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BepiColombo s first samples from Mercury

on 09 November 2021

The magnetic and particle environment around Mercury was sampled by BepiColombo for the first time during the mission’s close flyby of the planet at 199 km on 1-2 October 2021, while the huge gravitational pull of the planet was felt by its accelerometers.

The magnetic and accelerometer data have been converted into sound files. They capture the ‘sound’ of the solar wind as it bombards a planet close to the Sun, the flexing of the spacecraft as it responded to the change in temperature as it flew from the night to dayside of the planet, and even the sound of a science instrument rotating to its ‘park’ position.

Video credit: ESA/BepiColombo/ISA/ASI-INAF

The PHEBUS ultraviolet spectrometer collected data for an hour around the closest approach, focusing on the elements present in the planet’s extremely low-density atmosphere, or exosphere, which is generated either from the solar wind or from the planet’s surface. Clear peaks of hydrogen and calcium were recorded after the close approach, once BepiColombo exited the shadow of Mercury.

Hydrogen and calcium are just two examples of what can be found in the exosphere; once in orbit around Mercury, PHEBUS will characterise Mercury’s exosphere composition and dynamics in great detail, watching how it changes with location and time. PHEBUS is one of several spectrometers that will study Mercury from orbit to understand its surface composition, including looking for ice in permanently shadowed regions of high-latitude craters.

The data has been converted into sound to be audible to the human ear. The resulting sonification captures the changing intensity of the magnetic field and solar wind, including the moment the spacecraft crossed the magnetosheath ­– the highly turbulent boundary region between the solar wind and the magnetosphere around the planet.

Once in Mercury orbit, complementary magnetic field measurements made by both ESA’s MPO and JAXA’s Mercury Magnetospheric Orbiter (known as Mio) will lead to a detailed analysis of the planet’s magnetic field and its source, in order to better understand the origin, evolution and current state of the planet’s interior.

The October gravity assist manoeuvre was the first at Mercury and the fourth of nine flybys overall. During its seven-year cruise to the smallest and innermost planet of the Solar System, BepiColombo makes one flyby at Earth, two at Venus and six at Mercury to help steer it on course to arrive in Mercury orbit in 2025.

More details here.

Image credit: ESA/ATG medialab