NASA/Johns Hopkins University Applied Physics
Laboratory/Carnegie Institution of Washington

MIO - Mercury Magnetospheric Orbiter's New Name

June 08, 2018

JAXA selected MIO as new name for the Mercury Magnetospheric Orbiter (MMO) to be launched this Japanese fiscal year. Selection process is based on public response to the MMO renaming project made during the designated correspondence period, February 20 to April 9, 2018. Following are the details:

The New Name


Namesake and Background

  • The definition of the word mio in the original Japanese is a waterway or fairway. It is a fitting name denoting how far the MMO mission has come, navigating its course past important research and development milestones. It also carries the connotation of wishing the spacecraft a safe journey.
  • Historically, markers called mio-tsukushi were posted to guide boats sailing at rivers and sea. In traditional Japanese poetry, mio-tsukushi interchangeably means working hard without giving up. This describes the diligent and tenacious sprit of the MMO project team who never ceases to challenge.
  • The spacecraft will travel through the solar wind, a continuous stream of plasma that the Sun emits in the Mercury's magnetosphere. The Mercury's magnetospheric interference constantly affects the state of the solar wind in orbit. It conjures up the image of a sea vessel underway with its bow heading forward.
  • MIO is easy to say for many, especially those who do not speak Japanese.


Total number of correspondents: 6,494

19 suggested mio. 3 did Mio-Tsukushi.

The Selection Committee Members

Hajime Hayakawa, Project Manager, BepiColombo project team/Professor at the Department of Solar System Sciences, the Institute of Space and Astronautical Science

Go Murakami, Project Scientist, BepiColombo project team/Assistant Professor at the Department of Solar System Sciences, the Institute of Space and Astronautical Science

Chisato Ikuta, Director for Education and Public Outreach at the Institute of Space and Astronautical Science

Yasunori Matogawa, Emeritus at the Institute of Space and Astronautical Science

Naoko Takeuchi, Cartoonist

Acknowledgments by Hajime Hayakawa

I thank all who responded for your interest in the MMO. We are at the start of the mission with a long way ahead. I hope MIO will bring to us a lot of discoveries about the Mercury.


JAXA will send a gift to all who 19 proposers of Mio no sooner than July.


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