This article updates the one written in October 2024.
J-STORIES – Kyoto University and Sumitomo Forestry have successfully launched the world’s first wooden satellite into outer space. The cube-shaped satellite, which measures approximately 10 cm on each side, was deployed into orbit from the Japanese Experiment Module “Kibou” aboard the International Space Station (ISS) in December 2024.
According to Kyoto University, the satellite is now orbiting Earth and is expected to remain operational for approximately three months.
The satellite’s wooden structure has proven stable in the harsh conditions of outer space. Takao Doi, a former astronaut and a professor at Kyoto University’s Graduate School, expressed his satisfaction in an interview with J-Stories, stating that the success of the satellite shows that wood is a viable material for space applications.
The satellite was designed to transmit various information about its status to a ground station at Kyoto University. This includes measuring how different forces are affecting its shape and what the temperature is throughout its interior. It’s also relaying info about the geomagnetic forces that influence its trajectory as well as so-called soft errors that need to be corrected. However, as of Jan. 10, 2024, no signals have been received. Kyoto University speculates that the satellite’s power system may be temporarily down for unknown reasons. The team is still trying to establish communication with the satellite.
Kyoto University has already begun developing a second wooden satellite, twice as big as the first, which is scheduled for launch in 2027 or 2028.
Amid the intensifying competition in the space business, the issue of space debris — including defunct rockets and satellites — is increasingly pressing. If left unaddressed, this debris could lead to collisions between satellites and worsen atmospheric pollution upon reentry. One of Japan’s proposed solutions is the development of wooden satellites. Unlike conventional satellites made of aluminum or steel, which leave metal residues when burned up in the atmosphere, wooden satellites can significantly reduce environmental risks.
The wooden satellite deployed this time, classified as a CubeSat, was completed in May 2024 after four years of development and handed over to JAXA in June. It passed stringent safety reviews by both NASA and JAXA, marking the first official recognition of wood as a material for space use. The satellite was launched aboard SpaceX’s Falcon 9 rocket from Kennedy Space Center in Florida and later transferred to the ISS, where it was deployed from the Kibou module.
Wooden satellites have unique advantages. Wood allows electromagnetic waves to pass through, enabling antennas to be housed internally, thus simplifying the satellite’s structure and reducing potential failure risks. Additionally, the absence of moisture, oxygen, or bacteria in space ensures that the wood does not rot or burn.
However, the extreme environment of space presents challenges. The outer surface of the ISS experiences temperatures ranging from over 100 C in sunlight to below minus 100 C in shadow, all while exposed to intense cosmic radiation and ultraviolet rays. Ensuring the wood’s durability in such conditions remains a critical focus of the project.
According to Japan’s Cabinet Office, 2,368 satellites were launched into orbit worldwide in 2022, which is 11 times more than 10 years before. This sharp rise underscores the urgency of addressing space debris.
Translated by J-Stories (Anita De Michele, Mark Goldsmith)
Top page photo provided by Kyoto University and Sumitomo Forestry
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