After Jeff Bezos and Richard Branson, Yusaku Maezawa also flew to space.
The 46-year-old Japanese man, who made his fortune in online fashion, boarded a Russian rocket to reach the International Space Station (ISS), where he will spend 12 days.
The billionaire has set himself 100 tasks to accomplish in space and is expected to share his sound experience on his YouTube channel.
Before that and for long weeks, he and his assistant, who also takes part in the trip, prepared in Star City, a city built near Moscow in the 1960s to train generations of cosmonauts.
Read alsoSpace tourism: two Japanese tourists on a strange journey to the ISS
The mission of the two Japanese tourists is organized by Roscosmos, the Russian space agency, and its American partner Space Adventures.
Between 2001 and 2009, these two partners had already worked together to send extremely wealthy entrepreneurs into space eight times.
This trip marks Russia's return to orbital tourism.
This sector, in which it has lost ground against private American companies, in particular SpaceX, is experiencing renewed interest and constitutes a potential financial windfall.