TAMPA, Fla. — Pale Blue has raised an extra $8.5 million in venture capital to mass-produce water vapor propulsion systems and upgrade the technology, the Japanese small satellite thruster developer announced June 4.

The funding is on top of the $7.5 million the four-year-old University of Tokyo spin-off raised in October in loans and the first phase of Series B venture financing.

Jun Asakawa, Pale Blue’s co-founder and CEO, said the enlarged Series B funding round would support the creation of a 2,000-square-meter plant in the Ibaraki region near Tokyo for producing its Resistojet thrusters, designed for satellites weighing less than 10 kilograms.

Pale Blue successfully used Resistojet in orbit for the first time in March 2023, using jets of steam to move a tiny 6U cubesat.

Asakawa said several customers had flown satellites with the thrusters since then but did not name them.

The venture also plans to use the extra funds to accelerate the development of water-plasma propulsion technology for larger spacecraft up to 500 kilograms.

Also supported by a recent multiphase Japanese government grant worth up to $27 million, Pale Blue is developing water-based ion and hall-effect thrusters designed to use electricity and magnetic fields to accelerate propellant to improve efficiency.

Asakawa said the company aims to perform an in-orbit demonstration of the ion thruster next year and the hall-effect thruster in 2027.

Japanese early-stage investors Incubate Fund and Mitsui Sumitomo Insurance Venture Capital co-led the first phase of Pale Blue’s Series B funding round that closed in October, but did not participate in the extension. 

Investors that joined in its latest funding round include Astart, Global Brain, Itochu Technology Ventures, Gogin Capital and Chibagin Capital.

Jason Rainbow writes about satellite telecom, space finance and commercial markets for SpaceNews. He has spent more than a decade covering the global space industry as a business journalist. Previously, he was Group Editor-in-Chief for Finance Information...