Pale Blue details water ion thruster flight performance

(SpaceEnergy) Japanese propulsion developer Pale Blue has disclosed detailed in-orbit performance data from a water ion thruster demonstration, including 23 successful autonomous firings and 5.24 hours of cumulative thrust.

The 1U-class system uses electron cyclotron resonance (ECR) plasma generation and water as propellant. Pale Blue said ground testing recorded a 99.9% ignition success rate across 2,476 automated firing cycles, with a median time-to-thrust of 73 seconds.

Ground validation also demonstrated more than 7,000Ns of total impulse and successful operation of multiple thrusters without neutralisation interference.

During a 2025 low Earth orbit demonstration launched aboard SpaceX Transporter-14, the thruster successfully ignited on all 23 attempts and produced approximately 0.35mN of thrust, matching its ground-test design target.

Flight data also showed plasma ignition at spacecraft temperatures between 13.4°C and 17.3°C.

Pale Blue previously announced successful in-orbit operation of water propulsion systems in April 2026, but the newly published Small Satellite Conference paper provides the detailed quantitative flight-performance results.