The joint European-Japanese Mercury probe BepiColombo separated its European propulsion module on 3 September 2026, kicking off the critical arrival phase at its target planet. The separation took place at around 14:00 CEST and was streamed live from ESA’s ESOC control centre in Darmstadt, Germany.
Farewell to the transfer module
The Mercury Transfer Module (MTM) had steered the stack through the inner Solar System with ion thrusters ever since launch on 20 October 2018. After nine flybys of Earth, Venus and Mercury, its job is done. What remains are the two science orbiters: ESA’s Mercury Planetary Orbiter (MPO) and Japan’s magnetospheric orbiter Mio. ESA calls the arrival sequence one of the most operationally demanding it has ever attempted.
The roadmap to 2027
According to ESA, the paired orbiter is set to enter orbit around Mercury together in November 2026. In December, MPO and Mio will separate to take up their respective scientific orbits. Routine measurements are scheduled to begin in April 2027. That would make BepiColombo only the second spacecraft ever to circle the innermost planet.
Germany plays a prominent role: flight operations run from ESOC in Darmstadt, and the German Aerospace Center (DLR) contributes two instruments, the infrared spectrometer MERTIS and the BELA laser altimeter. MERTIS is designed to map the mineralogy of Mercury’s surface.
