Europe and Japan’s BepiColombo mission marked eight years in space on October 20, with its next major milestone about a month away: entering orbit around Mercury. ESA released an anniversary film on October 19, featuring the people preparing the mission for arrival. As of this article’s October 22 source check, the two science orbiters remain joined; Mercury orbit entry is planned for November 21.
One mission, two different views of Mercury
BepiColombo carries ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter, known as Mio. MPO’s instruments will examine the planet’s surface and interior, including its terrain, composition and gravity field. Mio will investigate the magnetic field, plasma, tenuous atmosphere and dust around Mercury. Measurements from two locations will help distinguish the planet’s own magnetic field from disturbances associated with the solar wind.
The transfer module has gone; the orbiters are still together
The Mercury Transfer Module (MTM) separated on September 3. It had supplied power and solar-electric propulsion during the long cruise. ESA confirmed the separation, which began a months-long arrival sequence. MPO’s chemical propulsion system now guides the remaining spacecraft stack toward Mercury.
That change also opened views previously obstructed by MTM. In its October 6 instrument update, ESA reported healthy initial results after MPO’s instruments were switched on together in September. These were checks in the new spacecraft configuration, ahead of routine orbital observations.
A camera test, not a new Mercury surface image
SIMBIO-SYS, MPO’s imaging and spectroscopy instrument, tested its three optical channels on September 15–16. The Paris Observatory reported successful operation, with the stereo channel recording stars. The first-light result confirms that the equipment works; it does not mean the camera has already begun its Mercury mapping campaign.
Once in its science orbit, SIMBIO-SYS is designed to combine stereo views, detailed images and visible-to-near-infrared spectral measurements. Together, these can connect the shape of the terrain with the materials on the surface, as explained in the Italian Space Agency’s October 6 report.
The dates ahead
The following milestones use ESA’s detailed mission timetable and arrival report. They are plans as of October 22, 2026, not completed events.
| When | Milestone |
|---|---|
| November 21, 2026 | MPO and Mio enter Mercury orbit while still joined. |
| December 9–10, 2026 | Mio separates from MPO for independent orbital operations. |
| March 2027 | MPO reaches its final science orbit after further orbit adjustments. |
| April 2027 | The mission’s routine science phase begins. |
Some anniversary material describes December as the arrival. The detailed schedule separates November’s initial orbit entry from December’s release of Mio; the two dates refer to different steps.
ESA’s anniversary film
Video: European Space Agency, published October 19, 2026.
Frequently Asked Questions
Has BepiColombo entered Mercury orbit yet?
Not as of October 22, 2026. ESA schedules the joined MPO and Mio spacecraft to enter Mercury orbit on November 21. Their separation is planned for December 9–10.
Why has the journey taken eight years?
The route uses repeated planetary flybys to reshape the spacecraft’s trajectory while saving propellant. Waiting for the required planetary alignments adds years; travel time is not simply a measure of Mercury’s distance from Earth.
When will routine science observations begin?
The mission’s routine science phase is planned for April 2027, after orbit adjustments and commissioning. Instruments have already gathered data during the cruise and flybys; April is not the start of all scientific activity.
Source check: October 22, 2026. The anniversary film was published October 19; the instrument reports were published October 6 and describe tests in September. Future dates follow ESA’s detailed arrival schedule.