PBH-100 water Hall thruster
Water-powered electric thruster for small satellites
Pale Blue
University of Tokyo spinoff that builds satellite thrusters running on water, a safe and cheap propellant. Its water thrusters have already flown on several missions in orbit.
SpaceNews (2025-01-08) reports a $16 million Series B but gives no date, so only the dated 2023 round is listed.
Products, by altitude
Low Earth orbit · 160–2,000 km
In development Testing ![]()
PBI water ion thruster
Water-fueled ion engine for small satellites
In service ![]()
PBR water resistojets
Small thrusters that push satellites with steam
Known rounds
| Date | Round | Amount |
|---|---|---|
| Oct 2023 | Venture round | $7.5M1 |
Milestones
- Jan 2025 Agreed with D-Orbit to fly two 2025 demonstrations of its 1U+ water ion thruster.2
Sources
Updated Oct 22, 2026 · How we source facts · Suggest a correction