Fourth Mercury flyby begins BepiColombo’s new trajectory

Science & Exploration

02/09/2024
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Groups from throughout ESA and business have labored constantly over the previous 4 months to beat a glitch that prevented BepiColombo’s thrusters from working at full energy. The ESA/JAXA mission continues to be on observe, with a brand new trajectory that may take it simply 165 km from Mercury’s floor on Wednesday.

Taking BepiColombo nearer to Mercury than it’s ever been earlier than, this flyby will scale back the spacecraft’s pace and alter its path. It additionally provides us the chance to snap photos and fine-tune science instrument operations at Mercury earlier than the primary mission begins. Closest method is scheduled for 23:48 CEST (21:48 UTC) on 4 September.

BepiColombo launched into house in October 2018 and is making use of 9 planetary flybys: one at Earth, two at Venus, and 6 at Mercury, to assist steer itself into orbit round Mercury. As soon as in orbit, the primary science section of the mission can start.

The upcoming flyby would be the fourth at Mercury. While it was all the time within the schedule, BepiColombo will get round 35 km nearer to Mercury than initially deliberate, as a consequence of a brand new route devised by ESA’s flight dynamics staff.

Why is it so arduous to go to Mercury?

Mercury is the least explored rocky planet of the Photo voltaic System, primarily as a result of getting there’s extremely difficult. As BepiColombo will get nearer to the Solar, the highly effective gravitational pull of our star accelerates the spacecraft in direction of it. What’s extra, the spacecraft launched from Earth with plenty of power, travelling far too rapidly to be captured into orbit round little Mercury.

Overcoming each of those hurdles could be enormously tough utilizing onboard thrusters alone. So BepiColombo additionally makes use of gravity help flybys to assist it lose power and decelerate sufficient to ultimately be captured into orbit round Mercury.

BepiColombo’s journey to Mercury turns into much more epic

BepiColombo is exclusive in that it includes two science orbiters that may circle Mercury – ESA’s Mercury Planetary Orbiter and the Japan Aerospace Exploration Company’s (JAXA) Mercury Magnetospheric Orbiter. The 2 are carried collectively to the mysterious planet by the Mercury Switch Module (MTM). In April 2024, BepiColombo began experiencing a problem that prevented MTM’s electrical thrusters from working at full energy.

Engineers recognized surprising electrical currents between MTM’s photo voltaic array and the unit accountable for extracting energy and distributing it to the remainder of the spacecraft. Onboard information suggest that that is leading to much less energy obtainable for electrical propulsion.

Mercury Switch Module with its ion thrusters firing

ESA’s BepiColombo Mission Supervisor, Santa Martinez explains: “Following months of investigations, we have now concluded that MTM’s electrical thrusters will stay working under the minimal thrust required for an insertion into orbit round Mercury in December 2025.”

A workaround to MTM’s diminished thrust has been cleverly devised by ESA’s Flight Dynamics staff. They conceived a brand new trajectory that maintains the baseline scientific mission at Mercury however permits the spacecraft to make use of decrease thrust in the course of the cruise section of the mission. With this new trajectory, BepiColombo is now anticipated to reach at Mercury in November 2026.

Every of BepiColombo’s fourth, fifth (December 2025) and sixth (January 2026) Mercury flybys are going forward as deliberate. All three will change the spacecraft’s pace and path, bringing it extra in tune with the orbit of Mercury across the Solar.

MTM will hearth its thrusters in September to October 2024 to place BepiColombo onto its new trajectory. The fourth flyby takes BepiColombo nearer than deliberate to Mercury, serving to scale back the propulsion wanted to achieve the fifth flyby. The sixth flyby will then be used to department onto the brand new trajectory.

Science at Mercury: a teaser of what’s to return

Past the later arrival date, the remainder of the BepiColombo mission is predicted to go forward as deliberate, and the scientific aims is not going to be affected. ESA expects the identical science to return out of the mission, with information gathered by a collection of 16 devices throughout the 2 orbiters.

Ten of those devices might be operated throughout this week’s flyby, giving us one other style of what scientific discoveries we are able to count on from the primary mission. Magnetic, plasma and particle monitoring devices will pattern the atmosphere earlier than, throughout and after closest method. The opposite devices can’t be operated as a result of their fields of view are blocked by the provider spacecraft.

“It’s so thrilling that BepiColombo can enhance our understanding and information of Mercury throughout these transient flybys, regardless of being in ‘stacked’ cruise configuration,” says Johannes Benkhoff, BepiColombo Mission Scientist.

“We get to fly our world-class science laboratory by way of numerous and unexplored elements of Mercury’s atmosphere that we received’t have entry to as soon as in orbit, whereas additionally getting a head begin on preparations to verify we’ll transition into the primary science mission as rapidly and easily as potential.”

Testing out the devices throughout flybys is efficacious for the science groups to examine that their devices are functioning accurately forward of the primary mission.

The simulation under exhibits the trail that BepiColombo will take by way of Mercury’s magnetic atmosphere in the course of the upcoming flyby. Varied devices will gather information on magnetic and electrical subject power, in addition to measuring the particles round Mercury, revealing completely new details about the planet’s magnetic atmosphere. Click on on the video to search out out extra.

BepiColombo’s greatest view but of Mercury

BepiColombo’s primary science digicam is shielded till the ESA and JAXA orbiters separate, however throughout flybys photos are taken by the three monitoring cameras (M-CAMs) on the Mercury Switch Module.

The cameras present black-and-white 1024×1024 pixel snapshots. Their photos of Mercury are a bonus: the cameras have been truly designed to observe the spacecraft’s photo voltaic array, antenna and magnetometer growth, particularly within the difficult interval after launch.

As BepiColombo passes Mercury, well-lit photos will start to be taken by M-CAM 2 and M-CAM 3 two minutes after closest method, when BepiColombo is round 200 km from Mercury’s floor. M-CAM 1 may have a lovely view of Mercury receding into the gap.

This flyby can even be the primary to take BepiColombo over Mercury’s poles, serving to to regulate the spacecraft’s trajectory to match that of Mercury, which is inclined in comparison with Earth’s orbit. We count on to have the ability to share BepiColombo’s first beautiful views of the planet’s south pole.

The primary photos will probably be downlinked just a few hours after closest method and are anticipated to be launched on 5 September. The closest photos are anticipated to disclose massive craters, wrinkle ridges, lava plains and rather more, serving to scientists unlock the secrets and techniques of Mercury’s 4.6-billion-year historical past and its place within the evolution of the Photo voltaic System.

All photos are scheduled to be launched publicly within the Planetary Science Archive later in September. The primary science outcomes from information collected in the course of the flyby will probably be launched on 13 September.