The target for the asteroid retrieval mission Hayabusa2 now has a name! Ryugu is leaving the undersea world of myth to take up residence in the main asteroid belt just in time to welcome a swarm of robotic visitors in 2018.

Ryugu is a 1-kilometer wide C-type asteroid with a higher probability of organic and hydrated materials than the S-type asteroid visited by the original ill-fated yet somehow-successful Hayabusa mission. Originally named 1999 JU3, asteroid 162173 was the subject of a naming contest.


Of 7,336 entries, 30 were for Ryugu, with another 13 related variations.

The name comes from an ancient story in Japanese culture, Urashima Taro. The main character retrieves a casket from Ryugu Castle at the bottom of the ocean. The name evokes the hope of finding water on the remote rock, and echoes back the theme of retrieving treasure from the distant asteroid back to the Earth.

The name met International Asteroid Union guidelines of not already existing anywhere else in the solar system, not running into trademark issues, and having an origin in mythology. It was already officially adopted much faster than the typical three-month waiting period.


The asteroid is the target of the Japanese space agency (JAXA) Hayabusa2 mission. The Hayabusa2 mission is unusual, even for asteroid sampling. It will drop a lander, blast the asteroid with an impactor to kick up dust, then bounce around the asteroid collecting samples before returning home. The spacecraft will also spill out a trio of rovers to explore the asteroid even more thoroughly. Between orbiter, lander, rovers, and markers, Ryugu will briefly be home to a small swarm of robots.

An earlier version of this article had the rovers coming from the lander, not Hayabusa2 directly. They’ll be scrambling out at different landing points to better explore the lump of rock. Thank you to Simon Tardivel for the correction!


[JAXA] via Planetary Society.

Artist’s concepts of the Hayabusa2 mission courtesy of Akihiro Ikeshita. Orbital diagram credit JAXA.

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