"From all things serious to silly questions that you were too afraid to ask astronauts, any questions are welcome! I will choose 100 and film myself trying them out for my YouTube channel," he wrote.
Maezawa made his fortune in online fashion retail and is now worth $2 billion. The space enthusiast said last week that he would travel to the ISS on the Russian Soyuz spacecraft from the Baikonur cosmodrome on December 8. The training begins in June.
The 45-year-old will fly to the orbital outpost together with his production assistant, Yozo Hirano. Russian cosmonaut Alexander Misurkin will be in charge of the mission. The space tourists, the first ones to travel to the ISS in more than a decade, will spend 12 days aboard.
SpaceX CEO Elon Musk said in 2018 that his company planned to send Maezawa to the moon as its first private customer by 2023.