Space Day

What Is Space Day?

Every September 12th is "Space Day" (宇宙の日, Uchū no Hi) in Japan. The date commemorates September 12, 1992, when astronaut Mamoru Mohri (毛利衛) became the first Japanese national to fly aboard the U.S. Space Shuttle — orbiting Earth aboard the Space Shuttle Endeavour as a payload specialist on the STS-47 mission. The day was established in 1992, International Space Year, by the Japan International Space Year Council, whose members included the Science and Technology Agency and the Institute of Space and Astronautical Science, and the date was chosen through a public call for proposals. As JAXA notes, the year "92" and the date "9/12" can both be read as "kyū-jū-ni" in Japanese, so the date is also a neat wordplay. (Mohri was actually the second Japanese person in space: TBS journalist Toyohiro Akiyama flew aboard a Soviet Soyuz in 1990.) Mohri's flight was a milestone in Japan's space program and a source of enormous national pride, inspiring a generation of young Japanese people to pursue careers in science, engineering, and space exploration.

Mamoru Mohri and STS-47

Mamoru Mohri, a materials scientist from Hokkaido, was selected as a payload specialist in 1985 to fly on the STS-47 "Spacelab-J" mission — a joint NASA-NASDA (Japan's National Space Development Agency, now JAXA) science mission with 44 experiments (24 in materials science and 20 in life sciences). The mission launched on September 12, 1992 and orbited Earth for nearly eight days, with Mohri conducting experiments in the pressurized Spacelab module. His selection and flight represented the culmination of Japan's first decade of participation in human spaceflight.

Japan's Space Program

JAXA (Japan Aerospace Exploration Agency), formed in 2003 by the merger of three predecessor agencies, operates Japan's space program across launch vehicle development, Earth observation satellites, planetary exploration, and human spaceflight. Japanese astronauts have served on the International Space Station (ISS), including long-duration missions as ISS commanders. Japan's H-II series of rockets and the HTV (Kōnotori) cargo spacecraft — which delivered supplies to the ISS — established Japan as a reliable partner in international space operations.

Japan's Planetary Exploration

Japan has achieved remarkable results in robotic planetary exploration. The Hayabusa (はやぶさ) and Hayabusa2 missions successfully collected samples from two different asteroids and returned them to Earth — an extraordinary technical achievement. The Kaguya (かぐや) lunar orbiter produced the first high-definition television images from lunar orbit. The Akatsuki (あかつき) mission studies Venus's atmosphere. These missions have established Japan as a leader in deep-space exploration science.

Fun Facts

• Hayabusa2: JAXA's Hayabusa2 spacecraft collected subsurface samples from asteroid Ryugu and returned them to Earth in December 2020 — a world first that is providing planetary scientists with pristine material from the early solar system.
• Kibo module: Japan's Kibo (希望, "Hope") module on the International Space Station is the largest single module on the ISS and includes a unique "JEM Small Satellite Orbital Deployer" — a mechanism for launching small satellites from the station into orbit.