Letara raises ¥2.6bn (roughly $16mn) for hybrid rocket engines the law does not call explosive

Letara, a Hokkaido University spinout, has raised about ¥2.6bn, roughly $16mn, for hybrid rocket engines that use plastic as fuel and are not legally classified as explosives. Germany’s HyImpulse raised €45mn for the same approach last October.

A Japanese startup has raised about $16mn to build rocket engines that burn plastic. Letara, a spinout from Hokkaido University, closed roughly ¥2.6bn in a round co-led by Headline Asia, JIC Venture Growth Investments and Incubate Fund.

The investor list is unusually institutional for a rocket company. Japanese banks, insurers and the car parts group Toyoda Gosei all took part, alongside venture arms of SMBC and Mitsubishi UFJ.

The engineering pitch is about what the propellant is not. Hybrid engines keep solid fuel and liquid oxidiser separate, so the propellant does not qualify as an explosive, which changes how it is stored, shipped and handled.

The idea is decades old and has always had the same problem. Stable ignition and thrust comparable to conventional engines proved hard to achieve, and Letara says its fuel design and patented ignition system now match solid motors and liquid bipropellant systems.

Size is the commercial argument. The company has miniaturised the engines to palm-sized units that fit small satellites, while the same approach scales up towards launch vehicles.

Demand appears to exist already. Letara has orders from rocket and satellite manufacturers and from the Japanese government, and is registered as a JAXA partner startup, though no contract values have been disclosed.

The next milestone is a firing test in orbit with an overseas partner. That is the step that separates a propulsion company from a propulsion paper.

Europe is further along in the same technology. Germany’s HyImpulse raised €45mn last October for hybrid orbital launch and is one of the firms competing in the European Launcher Challenge.

The competitive map is wider than either of them. Interstellar Technologies in Japan, Galactic Energy in China, InnoSpace in South Korea, Equatorial Space in Singapore and Gilmour Space in Australia are all working on hybrids.

The market they are chasing is still small. Hybrid propulsion was worth about $848mn in 2024 and is projected to reach $2.6bn by 2032, which is roughly one large satellite contract a year spread across six countries.

What has changed is that the idea is now funded rather than merely studied. That funding is arriving in a period when European private space investment has, for the first time, passed the United States.