The magnetometer aboard the Japanese orbiter (MMO-MGF) was developed and built under IWF lead, in cooperation with the Japanese Institute of Space and Astronautical Science (ISAS/JAXA) and the Technical University Braunschweig. MGF-O (outboard) was provided by European institutes and MGF-I (inboard) by ISAS/JAXA. In addition, IWF is responsible for the overall technical management of the magnetometer aboard the European orbiter (MPO-MAG, see photo). Both magnetic field instrument designs, MMO-MGF and MPO-MAG, are based on a digital fluxgate magnetometer with a dynamic range of approx. ±2,000 nT and a maximum vector rate of 128 Hz.
The primary objective of the magnetic field investigation on MMO (Mercury Magnetospheric Orbiter) is to study the formation and dynamics of Mercury's magnetosphere and the processes that control the interaction of the magnetosphere with the solar wind and with the planet itself. Emphasis will be placed on those effects and processes, which are particular to the Hermean magnetosphere and distinguish it from the better known terrestrial one: (1) the weak intrinsic magnetic field of Mercury and its interaction with the young and strong solar wind, (2) the comparably small dimension of Mercury's magnetosphere and possibly greater importance of plasma-kinetic effects, and (3) the near-absence of an ionosphere. It is expected that these differences have a large impact on (1) the reconnection process, both on the dayside and in the magnetotail, (2) the structure and dynamics of field-aligned currents, and (3) the low frequency plasma waves.
The primary objective of the magnetic field investigation on MPO (Mercury Planetary Orbiter) is to provide the magnetic field measurements that will lead to the detailed description of Mercury's planetary magnetic field, and thereby constrain models of the evolution and current state of the planetary interior. It is recognized that the scientific objectives of the BepiColombo mission can be best met by the comprehensive scientific coordination of the magnetic field investigations.