AstroX, a Japanese space technology company developing rocket launches from high-altitude balloons, announced on February 4 that it has completed the second close of its Series A funding round.
In the first close conducted in November 2025, the company secured ¥1.8 billion (approximately $12 million at the current exchange rate; the same applies hereinafter unless otherwise noted). The second close is believed to have raised an additional ¥520 million (approximately $3 million). AstroX has stated that the total amount raised in the Series A round amounts to ¥2.32 billion (approximately $15 million).
Founded in 2022, AstroX is headquartered in Fukushima Prefecture, Japan, where it also operates its research and development as well as manufacturing facilities.
What Is the “Rockoon” System Developing by AstroX?
AstroX’s business focuses on transporting payloads such as satellites from Earth into outer space. While this objective itself is not significantly different from that of other space technology companies, what distinguishes AstroX is its launch method.
The company first uses a balloon to carry a rocket into the stratosphere, after which the rocket is launched midair. AstroX refers to this approach as the “Rockoon” method.
Although this may appear to be a more complex process, the company claims that it can significantly reduce costs. According to AstroX, when compared with conventional small-scale rockets of a similar size, traditional launches typically cost around ¥1.5 billion (approximately $10 million) per launch, whereas a Rockoon launch can be conducted for about ¥500 million (approximately $3 million), roughly one-third of the cost.
AstroX estimates that launching 50 rockets per year at ¥500 million per launch would result in annual revenue of ¥25 billion.
While not officially disclosed, it is believed that launching rockets midair enables the simplification of vehicle structures and components, as well as eliminating the need for vast launch sites—factors that contribute to cost reductions.
At the same time as announcing this funding round, AstroX revealed that it successfully conducted an experiment in December 2025 in which a rocket was separated from its launch structure. The company aims to achieve a Rockoon launch reaching outer space sometime in 2026.
Funds to Be Used for Development and Hiring
The second close of the Series A round was backed by One Capital, Inclusion Japan, and other undisclosed angel investors.
The funds will be used for development activities and talent recruitment.
Shinji Asada, Founder, CEO, and General Partner of One Capital, commented on the investment, stating:
“We were strongly attracted to the AstroX management team’s highly integrated combination of strategic design capability, bold decision-making, and overwhelming technological strength.”
