Pale Blue Water-based Propulsion Systems

Pale Blue is a Japanese company founded in 2020 in Kashiwa, Chiba, that develops and manufactures propulsion systems for small satellites. It uses water as propellant, which is safe to handle, cheap and non-toxic, addressing the need for small satellites to change orbit, keep station and deorbit without hazardous fuels.

The product line runs from the 0.5U PBR-10 and 1U PBR-20 water resistojets for CubeSats, through PBR-30 and PBR-50 for nano- and microsatellites, to the 1U+ PBI water ion thruster with over 7,000 Ns total impulse and the PBH-100 Hall thruster for microsatellites. Each unit is a fully integrated module. Heritage customers include Sony, JAXA and the University of Tokyo.

• PBR-10: 0.5U integrated water resistojet for CubeSats running at 6 W.
• PBR-20: 1U water vapour propulsion system at 20 W.
• PBR-30 and PBR-50: larger resistojets with 3 to 12 mN and 10 mN thrust for nano- and microsatellites.
• PBI water ion thruster: 1U+ module with over 7,000 Ns total impulse for orbit maintenance.
• PBH-100 Hall thruster: 120 to 200 W system for micro- and small satellites.
• KIR-X module: combined ion and resistojet unit flown on JAXA's RAISE-4.

• Vietnamese satellite teams adding a PBR-20 module to a 3U or 6U CubeSat for orbit raising and deorbiting.
• Earth observation start-ups using a water ion thruster to maintain altitude and extend mission life.
• Satellite integrators in the region buying non-toxic propulsion to simplify launch safety approval.

• Water propellant is non-toxic and non-pressurised, simplifying handling, testing and launch approval.
• Compact modules from 0.5U fit CubeSats with tight volume and power budgets.
• Flight heritage on JAXA, Sony and University of Tokyo missions, including the RAISE-4 demonstration in 2026.
• AS9100-certified quality management for aerospace supply.

Space debris rules increasingly require small satellites to manoeuvre and deorbit, creating demand for compact propulsion. Green, non-toxic propellants lower costs and safety barriers for new satellite builders, including universities and agencies in Southeast Asia developing their first CubeSats.

Founded in 2020; headquartered in Kashiwa, Chiba, with a production facility in Tsukuba opened in 2026. Funded under Japan's SBIR Phase 3 programme, with additional funding announced in October 2026, and selected for a Space Strategy Fund project in January 2026. AS9100 certified in October 2026.