The spacecraft makes nine gravity help maneuvers (one of Earth, 2 of Venus and six of Mercury) prior to going into orbit around the inner planet of the Solar System in 2025. The BepiColombo PHEBUS spectrometer made its very first measurements of Mercurys tenuous atmosphere (exosphere) throughout the October 1-2, 2021 close flyby of the planet. The emission is seen as a function of time, which peaked as soon as BepiColombo left the shadow of Mercury (dotted area), shortly after closest method. The new BepiColombo flyby information– and ultimately information from its main science mission– will be compared with international magnetic field models created from the Messenger mission to produce the most accurate image yet of Mercurys magnetic field.
” On the velocity plots that were appearing on our screens, we could see the tidal impacts of Mercury on the BepiColombo structure, the drop of the solar radiation pressure during the transit in the shadow of the planet, and the movement of the center of mass of the spacecraft due to flexing of the big solar selections,” says Carmelo Magnafico of the Italian National Institute for Astrophysics (INAF).
Artist impression of BepiColombo zipping Mercury. The spacecraft makes 9 gravity help maneuvers (one of Earth, two of Venus and 6 of Mercury) before going into orbit around the inner planet of the Solar System in 2025. Credit: ESA/ATG medialab
The magnetic and particle environment around Mercury was tested by BepiColombo for the very first time throughout the objectives close flyby of the world at 199 km on 1-2 October 2021, while the huge gravitational pull of the world was felt by its accelerometers.
The magnetic and accelerometer data have been converted into sound files and provided here for the first time. They capture the noise of the solar wind as it bombards a world near the Sun, the flexing of the spacecraft as it reacted to the change in temperature level as it flew from the night to dayside of the world, and even the noise of a science instrument rotating to its park position.
Uncharted territory
” It may have been a fleeting flyby, but for a few of BepiColombos instruments, it marked the beginning of their science data collection, and an opportunity to actually begin getting ready for the primary mission,” states Johannes Benkhoff, ESAs BepiColombo job scientist. “These flybys also provide the possibility to sample areas around Mercury that will not be accessible once were in orbit. In this case, BepiColombo provided us insight into the particles provide near to the planet, in addition to the electromagnetic field borders as it traversed through the magnetosphere at higher ranges.”
The PHEBUS ultraviolet spectrometer collected data for an hour around the closest technique, concentrating on the components present in the planets extremely low-density atmosphere, or exosphere, which is produced either from the solar wind or from the worlds surface area. Clear peaks of hydrogen and calcium were tape-recorded after the close method, when BepiColombo left the shadow of Mercury.
Hydrogen and calcium are simply two examples of what can be found in the exosphere; when in orbit around Mercury, PHEBUS will define Mercurys exosphere composition and characteristics in great detail, seeing how it alters with location and time. PHEBUS is among numerous spectrometers that will study Mercury from orbit to understand its surface structure, including trying to find ice in permanently watched areas of high-latitude craters.
The BepiColombo PHEBUS spectrometer made its first measurements of Mercurys rare environment (exosphere) during the October 1-2, 2021 close flyby of the planet. The two brightest detections are displayed in this uncalibrated quick-look data plot, highlighting the presence of calcium and hydrogen. The emission is viewed as a function of time, which peaked as soon as BepiColombo left the shadow of Mercury (dotted region), soon after closest approach. The green line represents the range from Mercury. Credit: ESA/BepiColombo/PHEBUS, LATMOS/CNES, IKI/Roscosmos, DESP/JAXA
During the flyby, the Mercury Gamma-ray and Neutron Spectrometer (MGNS) was also operated, identifying brilliant fluxes of neutron and gamma rays. These emissions are known to be produced by the interaction of galactic cosmic rays with the uppermost surface area layers of Mercury, and also supply information about the surface composition. A detailed analysis of the information– also from the Venus flyby– is presently in development.
Magnetic borders
Sensing units on the magnetometer boom– the structure seen extending from the Mercury Planetary Orbiter (MPO) in some of the MCAM images — taped details of the solar wind and electromagnetic field around Mercury. Throughout this flyby, the magnetometer team were especially thrilled to collect information from so close over the planets southern hemisphere; so far, only Mercurys northern hemisphere has been magnetically surveyed by NASAs Messenger objective.
” Its like having just checked out North America and seeing South America through field glasses, but unfortunately needing to abort the exploration. As a researcher, youre desperate and naturally curious to return,” states Daniel Heyner from TU Braunschweig in Germany, who leads the MPO magnetometer researcher group. “That makes this flyby especially fascinating, as it is the very first time that data from the planets southern hemisphere close to the surface is readily available– even if it is just a little sample.”
The information has actually been converted into sound to be audible to the human ear. The resulting sonification captures the altering intensity of the electromagnetic field and solar wind, consisting of the moment the spacecraft crossed the magnetosheath — the extremely unstable border region between the solar wind and the magnetosphere around the world.
As soon as in Mercury orbit, complementary magnetic field measurements made by both ESAs MPO and JAXAs Mercury Magnetospheric Orbiter (understood as Mio) will result in a comprehensive analysis of the planets electromagnetic field and its source, in order to better understand the origin, development and existing state of the worlds interior. Furthermore, the 2 orbiters will take a trip through different locations of Mercurys magnetosphere and on various timescales, determining at the same time how the magnetic field modifications in time and in space, and its relationship to the powerful solar wind.
In the meantime, Daniel and his associates will start to follow up on questions such as: can the attributes of the electromagnetic field from the northern hemisphere be easily transferred to the southern hemisphere? Has the magnetic field created by the dynamo maybe even changed in the last six years after the Messenger objective– as it continually does on Earth? The brand-new BepiColombo flyby data– and eventually data from its main science objective– will be compared to international magnetic field models developed from the Messenger mission to produce the most accurate photo yet of Mercurys electromagnetic field.
Feeling the crunch
The Italian Spring Accelerometer (ISA) onboard the MPO tape-recorded the velocities measured by the spacecraft as it experienced the severe gravitational pull of the world during the flyby, and the action of the modification in temperature level as the spacecraft went into and exited the shadow of the planet. ISA found the motion of the PHEBUS spectrometer as it clicked back into its parking bracket after it finished its operations at Mercury.
” On the acceleration plots that were appearing on our screens, we might see the tidal results of Mercury on the BepiColombo structure, the drop of the solar radiation pressure throughout the transit in the shadow of the world, and the movement of the center of mass of the spacecraft due to flexing of the big solar varieties,” says Carmelo Magnafico of the Italian National Institute for Astrophysics (INAF). “The genuine science starts now for us, due to the fact that in the distinction in between those anticipated results and the in fact determined data stands the ISA clinical value. We are extremely pleased.”
Timeline of flybys during BepiColombos 7.2 year journey to Mercury. Credit: ESA
ISA will support the study of Mercurys internal structure and test Einsteins theory of General Relativity to an extraordinary level of accuracy. It will likewise be main to supplying precise orbit decision of the MPO around Mercury, and of Mercurys center of gravity as it orbits around the Sun.
The October gravity help maneuver was the very 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, 2 at Venus, and six at Mercury to assist guide it on course to show up in Mercury orbit in 2025.
