At 2 p.m. local time in Germany, mission control sent the separation command. After almost two hours for the signal to travel more than 120 million miles, the spacecraft confirmed that the module had drifted away, leaving a slimmer stack of two orbiters and a sunshield about 2.1 million miles from Mercury.

The Mercury Transfer Module, or MTM, is a car‑sized unit that provided solar power and ion‑engine thrust for a series of flybys of Earth, Venus and Mercury. It has been attached to BepiColombo for the whole six‑year cruise.

Removing the MTM made the spacecraft lighter, which improves its ability to steer precisely during the final approach. It also uncovered the scientific cameras that were previously blocked. “Finally, we have science cameras,” said Paolo Cappuccio, a European Space Astronomy Centre scientist in Spain. “Let’s go to Mercury.”

The separation marks the end of the long cruise and the beginning of the months‑long arrival phase, during which engineers will fine‑tune the trajectory so the probe can be captured by Mercury’s gravity. The mission will later have to endure Mercury’s extreme temperature swings, but the lighter configuration is now ready for the delicate orbital maneuvers and scientific observations.