The European Space Agency reported that BepiColombo's Mercury Transfer Module separated from the spacecraft stack on 3 September 2026, with signal confirmation received at 15:49 CEST by the mission control team in Darmstadt, Germany. According to ESA's 7 September account, the module had carried the mission through 9.9 billion kilometres and nine planetary flybys over eight years, supplying power and solar electric propulsion.

Separation is the opening move in a sequence ESA describes as one of its most complex planetary arrivals. The remaining stack is still more than three million kilometres from Mercury and will use the Mercury Planetary Orbiter's chemical propulsion to adjust its trajectory before orbit insertion on 21 November. The Mercury Magnetospheric Orbiter, Mio, is to be deployed in early December, with the Planetary Orbiter guided into its science orbit in March 2027 and joint science beginning by April 2027.

The now inoperable transfer module, which has no antenna or onboard computer of its own, will remain in a stable orbit around the Sun, ESA said. The agency said the mission is intended to become the first to place two spacecraft in orbit around Mercury.