BepiColombo Reaches Mercury Orbit in November After 8-Year, 9-Flyby Journey

Q: After an eight-year journey and a thruster scare, what is the greatest remaining hurdle for BepiColombo’s arrival at Mercury?

The biggest remaining hurdle is BepiColombo’s orbital insertion at Mercury: a tightly timed, technically delicate arrival sequence in which the spacecraft must shed just enough speed for Mercury to capture it. That is difficult because Mercury is one of the hardest planets to reach. Falling inward toward the Sun makes a spacecraft move extremely fast, so BepiColombo must execute a precise series of low-thrust maneuvers rather than a single dramatic braking burn. Engineers have described this as the mission’s most critical phase, requiring exact navigation, careful speed trimming, and a “weak capture” into a polar orbit. The challenge is heightened by the 2024 thruster problem, which reduced propulsion performance and forced a redesigned trajectory. Although the extra flybys preserved the science mission, they left little room for error in the final approach. The spacecraft must also separate its transfer module and then place the two orbiters, ESA’s MPO and JAXA’s Mio, into their intended configurations without disrupting the capture sequence. In short, after surviving the long cruise and the thruster scare, the main test is whether BepiColombo can carry out the precise choreography of arrival—module separation, controlled braking, and stable capture into Mercury orbit—under reduced propulsion margins and extreme conditions near the Sun.

2 articles · Updated · spacedaily.com · Jul 2

November 2026 will bring BepiColombo’s long-awaited Mercury capture, making it only the third mission to visit the planet and just the second to enter orbit.
Nine flybys — one of Earth, two of Venus and six of Mercury — plus years of ion-engine thrust gradually bled off speed, the key challenge in reaching the Sun’s innermost planet.
An April 2024 thruster-power problem forced engineers to redesign the approach and delayed orbit insertion by about 11 months from December 2025, but preserved the full science mission.
Two orbiters will separate after arrival: Europe’s Mercury Planetary Orbiter to study the surface and interior, and Japan’s Mio to examine Mercury’s magnetic field and surrounding environment.
Science operations are expected in 2027, targeting Mercury’s oversized iron core, persistent magnetic field and suspected water ice in permanently shadowed polar craters.

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BepiColombo Spacecraft to Orbit Mercury in November After Eight-Year Journey

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3 November 1973 - NASA's Mariner 10 became the first mission sent to study Mercury. Using the first-ever gravity assist maneuver at Venus, it flew past Mercury three times and revealed a

After an eight-year journey and a thruster scare, what is the greatest remaining hurdle for BepiColombo’s arrival at Mercury?

Could Mercury’s polar ice hold the chemical secrets to the origin of water in the inner solar system?

How will data on Mercury's giant core challenge our theories on how rocky planets, including Earth, are formed?

BepiColombo at Mercury: Engineering Triumphs, Scientific Breakthroughs, and the 2026 Orbit Insertion Milestone

Overview

The BepiColombo mission is now in its final approach to Mercury, preparing for orbit insertion in November 2026 after a complex journey through the inner Solar System. Using an advanced electric propulsion system that adjusts thrust based on solar power, the mission has reduced propellant needs and provided valuable data for future technology. Engineers have carefully reviewed propulsion performance, leading to important insights for upcoming missions. Throughout its cruise phase, BepiColombo achieved major milestones, including multiple planetary flybys, and overcame technical challenges, all while setting the stage for groundbreaking scientific exploration of Mercury’s surface, interior, and magnetic environment.

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