BepiColombo has left the propulsion module: the arrival maneuver at Mercury has begun

The BepiColombo mission, conducted jointly by the European Space Agency and the Japanese agency JAXA, began arrival operations at Mercury on September 3, 2026. The first step was the separation of the propulsion module from the rest of the probe.

It is a maneuver that closes one phase and opens another. The propulsion module is the part that carried the assembly to the vicinity of the planet; once its task is complete it is jettisoned, and what remains is the scientific payload, which must be captured by Mercury’s gravity.

What happens now

Entry into orbit around the planet is expected by the end of 2026; industry reconstructions indicate November 6th as the date. After insertion, the mission will split into two separate spacecraft: the ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter — known as Mio.

The two orbiters have different, complementary tasks. The first is dedicated to the planet’s surface and interior; the second to its magnetic field. It is an architecture that responds to a physical constraint: observing the crust and observing the magnetosphere require different orbits and instruments, and a single spacecraft cannot do both well.

On the quality of the sources

On this piece we must be explicit about the material we have. The two available sources are a 2026 spaceflight timeline, which compiles updates from the two agencies, and a schedule of scientific missions published by NASASpaceflight. Neither is a primary official statement from the ESA or JAXA.

This means we report the sequence — module separation on September 3rd, insertion by year’s end, subsequent division into the two orbiters — with the degree of certainty the available sources allow, not with that of an agency document. Should different dates emerge in an official communication, we will report it.

The rule this newspaper applies to corporate press releases, which we extend to industry schedules, applies here: a programmatic announcement describes an intention, not a result. The module separation has occurred; the orbital insertion is planned.

What we don’t know

We do not know the detailed technical outcome of the separation: we know that arrival operations began with that maneuver, not which parameters were recorded. We do not have the sequence of intermediate maneuvers between September 3rd and the insertion.

We do not know whether the November 6th date is confirmed by the agencies or is a schedule indication: in the available material it appears as a date indicated in industry reconstructions, and we report it with this qualification.

We do not have, finally, the scientific program of the two orbiters after entering orbit, nor the expected duration of their respective operational phases.

The verifiable fact is the date of September 3, 2026 and the maneuver that marked it: from that moment BepiColombo proceeds without the module that propelled it this far, and the next public checkpoint of the mission will be the orbital insertion around Mercury, expected by the end of the year.

Sources: 2026 in spaceflight — Wikipedia (compiled from ESA/JAXA updates); NASASpaceflight.