Mamoru "Mark" Mohri ( , Mri Mamoru, born 29 January 1948), AM is a Japanese scientist, a former NASDA astronaut, and a veteran of two NASA Space Shuttle missions. He is the first Japanese astronaut who was part of an official Japanese space program. The first Japanese person in space, Toyohiro Akiyama, was a journalist who was trained in the Soviet Union.

Takao Doi (土井 隆雄, Doi Takao, born September 18, 1954) is a Japanese astronaut, engineer and veteran of two NASA Space Shuttle missions.

Doi holds a doctorate from the University of Tokyo in aerospace engineering, and has studied and published in the fields of propulsion systems, and microgravity technology. He researched at the Institute of Space and Astronautical Science and was selected by NASDA as an astronaut candidate in 1985 for the Japanese manned space program while also conducting research in the United States at NASA's Lewis Research Center and the University of Colorado at Boulder. Doi flew as a mission specialist aboard STS-87 in 1997, during which he became the first Japanese astronaut to conduct a spacewalk.

He received a Ph.D. in 1983 from the University of Tokyo, and also a PhD in Astronomy from Rice University in 2004.

Takao Doi visited the International Space Station in March 2008 as a member of the STS-123 crew. STS-123 delivered the first module of the Japanese laboratory, Kibō, and the Canadian Dextre robot to the space station. During this mission, he became the first person to throw a boomerang in space that had been specifically designed for use in microgravity during spaceflight.Doi retired from astronaut duty and worked as the chief of Space Applications Section of United Nations Office for Outer Space Affairs, starting in September 2009.In April 2016, he became a professor at the Unit of Synergetic Studies for Space of Kyoto University, and then at the Graduate School of Advanced Integrated Studies in Human Survivability (GSAIS) since April 2020.As an avid amateur astronomer, he discovered supernovae SN 2002gw and SN 2007aa.