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MPO : Mercury Planetary Orbiter Japanese page>>
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MPO [Mercury Planetary Orbiter] : Objectives
The MPO spacecraft is set up mainly for the studies of surface and internal structure of Mercury. ESA will develop and operate to and on the Mercury orbit.

Mercury was formed in the area nearest to the sun.
The unique interior and unique surface, such as a huge main nucleus, serve important keys for the origin and evolution of planets in solar system formation.

The MPO spaccraft aims at the following targets:
  • Internal structure of Mercury
    with huge iron core (3/4 of the whole radius) will be investigated with detailed all sphere mapping of gravity and magnetic field.
  • The geology with the figures remained from early stages of formation
    including all surfaces provides the important information for the origin and evolution of Mercury.
  • Mineral and element compositions
    acquire keys to the origin of Mercury, by the remote sensing of infrared, UV, X-ray, a gamma ray, and neutron, and direct measurement of the gas emitted from the surface.
  • Ice in the polar region
    Verify the existence of 'water ice' by the gamma ray and neutron observation.
MPO spacecraft: Overview
The MPO is a 3-axis controled spacecraft.
This is for continuing attitude control of the cameras and various spectrometers / sensors toward the planet surface directly below the spacecraft.
Since the continuous aiming of the MPO spacecraft enables much high-quality observations.
To guard from powerful sunlight, the sun shield side is continuously covering the spacecraft in order to keep the temperature of the spacecraft in moderate level.

MPO orbit is near the circle, with altitude of "400km at periherm and 1500km at apoherm", in order to make detailed mapping of surface and internal structure.

MPO works as 'a head' of the Mercury Composite System (MCS), joint system of MPO, MMO and propulsion modules "SEPM" (electric propulsion module) and "CPM" (chemistry promotion module).
After arrival, the MPO separete SEPM, MMO, and CPM, and will act as an independent orbiter around Mercury.
The MPO spacecraft will be operated by ESA / ESOC (European Space Operation Center) in Germany.
MPO spacecraft: Payload Selection
Payloads for MMO and MPO spacecraft was selected by the international payload review comittee in fall 2004. Now, several joint payload teams with Japanese and European scientists actively make design and development efforts. Moreover, the observation plan after the Mercury arrival will draw up and carry out by the "BepiColombo Science Working Team" which involved in not only the payload development members but also the theoretical researchers in both Europe and Japan.
BepiColombo: Spacecraft
Japan Aerospace Exploration Agency (JAXA) Institute of Space and Astronautical Science (ISAS) European Space Agency (ESA) BepiColombo Project (ESA)
BepiColombo, a cooperative mission by Japan Aerospace Exploration Agency (JAXA) / Institute of Space and Astronautical Science (ISAS) and European Space Agency (ESA), will explore Mercury, the planet closest to the Sun. ISAS/JAXA is building one of the main spacecraft, the Mercury Magnetospheric Orbiter (MMO), and ESA will contribute the other, the Mercury Planetary Orbiter (MPO).
[Mercury exploration] JAXA >> ISAS >> [Space Plasma Group, ISAS/JAXA]
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