The BepiColombo spacecraft initiated its arrival sequence at Mercury on September 3, 2026, marking the start of orbital entry operations after nearly eight years in transit. Flight controllers at ESA verified the milestone following telemetry updates received at 11:31.
The maneuver detached the Mercury Transfer Module from the rest of the spacecraft stack after ground stations confirmed the expected Doppler frequency shift.
The separation proceeded as planned.
Jointly built by ESA and JAXA, the mission lifted off from Earth in October 2018. The craft traveled more than 10 billion kilometers through the inner Solar System to reach its target.
Orbital entry schedule targets late November
Engineers now steer the remaining stack through a series of trajectory corrections toward the planet. The spacecraft will slip into orbit around Mercury on November 21, 2026.
Ground controllers will split the two scientific orbiters during operations scheduled for December 2026.
Both orbiters will activate their primary research payloads to collect scientific data beginning in April 2027.
Scientific payloads divide mission tasks
The two orbiters carry distinct instrument packages designed to study the planet from complementary vantage points.
- Mercury Planetary Orbiter, built by ESA, maps surface topography and measures chemical composition.
- Mercury Magnetospheric Orbiter, supplied by JAXA, analyzes the surrounding magnetic field and planetary exosphere.
Complex braking required nine gravity assists
Operating under joint management by ESA and JAXA, the mission carried out nine separate planetary flybys across the inner Solar System to bleed off enough orbital momentum for the spacecraft to match the high speed of Mercury without exhausting its fuel supplies.
Mercury presents steep orbital challenges.
Controllers permanently switched off the solar electric thrusters of the transfer module in June 2026 ahead of the final coasting arc.
Instruments target geological anomalies and high density
Only NASA had previously operated close to the planet, collecting observations during the Mariner 10 and Messenger flights. BepiColombo plans to photograph surface depressions known as hollows.
Scientists aim to determine why Mercury possesses an unusually dense internal core. One working hypothesis suggests an ancient cosmic impact stripped away the outer silicate layers of the planet during the early history of the Solar System.
Data gathered by the two orbiters will evaluate that impact model.