I S A S / Public Outreach: "International Joint Mercury Exploration Mission “BepiColombo” Moves to Next Stage after Review by SAC
The only direct spacecraft observation of the planet Mercury was provided by the US Mariner 10’s flyby in the 1970s. Mariner 10 revealed many unexpected findings about the planet nearest the Sun, including, for example, the unexpected presence of a magnetic field and magnetospheric activities. Further investigation into those findings has been on hold for over 30 years.

The Mercury exploration working group was formed at ISAS in 1997. It developed a Japanese-initiated Mercury exploration plan the following year. In 1999, ESA (European Space Agency) proposed a joint Mercury exploration, and ISAS agreed to participate in 2000. In the same year, the BepiColombo mission was formally selected as one of ESA’s cornerstone missions. The mission was formally authorized by ISAS in early 2002, following submission to and review by the Space Science Committee in 2001."
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