BepiColombo is a joint European Space Agency (ESA) and Japanese mission to Planet Mercury for exploration. BepiColombo is ESA’s first mission to Mercury. It is also ESA’s first mission conducted in co-operation with Japan.

BepiColombo at Planet Mercury

BepiColombo was launched on 20 October 2018 on an Ariane 5 rocket from ESA’s Spaceport in Kourou, French Guiana. The spacecraft will arrive at Planet Mercury in December 2025 for a 1 year nominal mission with a possible 1-year extension. 

BepiColombo will use the gravity of the Earth, Venus and Mercury in combination with solar-electric propulsion (SEP) to journey to Mercury. When approaching Mercury, the spacecraft will use the planet’s gravity plus conventional rocket engines to insert itself into a polar orbit.

The main contractor for BepiColombo project is Airbus Defence and Space. It is building the European Mercury Planetary Orbiter and the Mercury Transfer Module.


The aim of the BepiColombo mission is:

1. To investigate Planet Mercury’s magnetic field, magnetosphere and both its surface and interior.

2. To make a complete map of Mercury at different wavelengths. This will allow to map the planet’s mineralogy and elemental composition and determine whether the interior of the planet is molten or not.

3. To examine Mercury as a planet: composition, craters, geology and interior structure.

4. To examine Mercury’s thin atmosphere.

5. To use the spacecraft’s proximity to the Sun to test the predictions of General Relativity theory with improved accuracy.

6. To understand the origin and evolution of a planet close to its parent star (our Sun).

The total estimated cost of the mission is 650 million euros (in June 2013).


Launch Mass: 4100 kg
Mercury Planetary Orbiter in Mercury orbit: 1150 kg
Mercury Magnetospheric Orbiter in Mercury orbit: 275 kg


The BepiColombo spacecraft consists of:

1. Mercury Planetary Orbiter (MPO)

The main spacecraft is ESA’s Mercury Planetary Orbiter (MPO). It will map the planet and study the surface and internal composition of Planet Mercury.

2. Mercury Magnetospheric Orbiter (MMO)

It will observe the magnetic field and the magnetosphere. Japan’s JAXA is responsible for the Mercury Magnetospheric Orbiter (MMO).

3. Mercury Transfer Module:

It contains four T6 ion thrusters which are located at the bottom of the spacecraft. The module will carry both orbiters.


BepiColombo mission is named after Giusseppe (Bepi) Colombo (1920-1984) a scientist, engineer and mathematician at the University of Padua, Italy. He was the first to see that an unsuspected resonance is responsible for Mercury’s habit of rotating on its axis three times for every two revolutions it makes around the Sun. He also suggested to NASA how to use a gravity-assisted swing-by of Planet Venus to place the Mariner 10 spacecraft in a solar orbit that would allow it to fly by Mercury three times in 1974-5.

BepiColombo Spacecraft

Operations Centre

Mission operation centre will be located at the European Space Operations Centre (ESOC) in Darmstadt, Germany. The ground telemetry station for the MPO and MMO spacecraft will be the Cebreros (Spain) 35m antenna (8 hours/day) and the Usuda (Japan) 64m antenna (6-8 hours/day) respectively.


The European mission to Planet Mercury was first proposed in May 1993. ESA included a Mercury orbiter in one of the three new Cornerstones missions when the Horizon 2000 science programme was extended in 1994. ESA approved a package of missions for 2008–2013 including BepiColombo and Gaia in October 2000.

In 2003 an original plan to include a lander was shelved.

In 2008 following an increase in BepiColombo mission’s mass the launch vehicle was changed from Soyuz-Fregat to Ariane 5.

Japan sent the Mercury Magnetosphere Orbiter (MMO) in April 2015 to the European Space Research and Technology Centre (ESTEC), Netherlands for testing.

In November 2016 the launch was rescheduled to October 2016 because an electrical fault was found during preparations for the Mercury Transfer Module thermal test.


Europe’s Space Programme: To Ariane and Beyond by Brian Harvey

Did you know?

* The proximity of Mercury to the Sun makes it difficult to observe and hard to reach by space flight.

* BepiColombo and Solar Orbiter are ESA’s first long-range science missions designated to use an ion engine.

*  NASA’s Mariner 10 was the first spacecraft to flyby Planet Mercury. It made three fly-bys in 1974 /75. It returned the first close-up pictures of the planet. The next spacecraft to orbit Mercury was NASA’s MESSENGER spacecraft in 2011.

* Magnetosphere is the region of space around the planet that is dominated by its magnetic field.

BepiColombo Links

ESA Science & Technology: BepiColombo: The official site for this European Space Agency mission to Mercury. Includes mission summary, background science, and current status.

Mercury project: BepiColombo: The official site for the Institute of Space and Astronautical Science (ISAS) and Japan Space Exploration Agency (JAXA) portion of the BepiColumbo mission

L’Europe ira sur Mercure by ESA (Photo reference – 2 Oct 2011)

JAXA | Mercury Exploration Mission “BepiColombo”: Japan Aerospace Exploration Agency

BepiColombo Overview: Picture source – Artist’s view of BepiColombo at Mercury (released 26/02/2007) by EADS Astrium.

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