High-Impulse Water Propulsion Utilising the TunaCan Volume for Enhanced Mission Endurance.
The TunaTank Thruster is a safe, high-performance electrothermal propulsion system that utilises low-pressure water to deliver up to 50x more thrust than traditional electric propulsion. Its unique semi-external design leverages the “tunacan” volume of CubeSat deployers, allowing for increased propellant storage in a bespoke fuel tank inside CubeSats or small satellites.
Maximum Volumetric Efficiency: Utilising "Dead Space"
In the space industry, volume is a premium commodity. TunaTank solves the “cylinder problem” by offering conformal fuel tanks designed to fit the unique internal architecture of your satellite.
- Tailored Geometry: We 3D-print tanks to utilize the irregular “dead space” inside standard 3U, 6U, and 12U frames and even bigger small satellite frames.
- Increased Delta V Budget: By filling corners and gaps that standard tanks leave empty, you can carry more propellant without increasing your satellite’s external dimensions.
- Optimised Centre of Mass: Customise the tank shape to balance your satellite’s mass distribution, simplifying your AOCS requirements.
- Payload is thermally isolated: The thermal node is located outside the CubeSat frame within the “tunacan” volume of the deployer and is physically separated from the payload by the integrated water propellant tank, which acts as a natural thermal barrier.
The SteamJet TunaTank Thruster features a high-performance, 3D-printed architecture designed for maximum volumetric efficiency. The system is divided into two primary sections: a customizable internal water tank that occupies “dead space” within the CubeSat frame, and a cylindrical thruster module optimised for the “tunacan” volume of the deployer.
These sections are joined by a robust mechanical mounting interface, allowing for seamless integration into the satellite’s aft structure. The external thruster face features a precision-engineered supersonic nozzle for steam ejection and an accessible fueling port for pre-flight readiness. Data and power are delivered via a high-reliability electrical connector (RS-422/TTL), ensuring a true “plug-and-play” integration with the spacecraft bus.
All-in-One Mechanical Integration
The TunaTank is not a kit of parts; it is a hermetically sealed, self-contained orbital manoeuvre unit. We’ve eliminated the complexity of external piping and driver boards.
- Integrated Power & Control: Onboard electronics handle thermal management, telemetry, and firing logic via a single I2C/UART/RS-422 interface.
- Structural propellant tank: The housing serves as the low-pressure vessel and the primary mounting structure, reducing part count and failure points.
- Adaptable design: We could customize TunaTank internal volume, maximizing propellant capacity by filling all space not occupied by the payload.
Technical Specifications
METRIC | VALUE | ENGINEERING IMPACT |
|---|---|---|
SYSTEM WET MASS | ~0.9 kg | Minimal impact on CoG and moment of inertia. |
SPECIFIC IMPULSE | 172 s | Efficient for orbital manoeuvring. |
Thrust Level | 5 – 20 mN | High-fidelity control for constellation phasing. |
PROPELLANT TYPE | Water | Green-label; simplified Range Safety approval. |
TOTAL IMPULSE | Up to 600 Ns | Sufficient for multi-year station keeping, collision avoidance & deorbiting. |
INPUT POWER | < 20 W (Peak) | Compatible with standard CubeSat power rails. |
Safety & Launch Compliance
Low-Risk Path to Orbit. The TunaTank utilises water — a non-hazardous, low-pressure media that simplifies the safety vetting process for secondary payloads. It is designed to meet NASA GSFC-STD-7000A and ECSS standards, ensuring that your propulsion system is never the bottleneck in your launch schedule.
Maximising Mission Capability
The SteamJet TunaTank Thruster propulsion system is not just an auxiliary module; it is a mission enabler. By customising the fuel tanks to fill all space available inside the 3U-16U CubeSat structure or small satellite, mission designers can implement capabilities that are mandatory for small satellites:
Precision Phasing & Constellation Deployment
Deploy your fleet from a single launch and use the TunaTank thrusters to phase satellites into their respective slots.
Active Collision Avoidance
With its low-vibration profile and rapid response time, the system provides high-confidence manoeuvring to protect your high-value optical or RF instruments.
Orbit Raising & Maintenance
Extend the life of your LEO mission by counteracting atmospheric drag.
Responsible De-orbiting
Frequently Asked Questions
The thruster features a unique shape factor designed to fit within the “tunacan” volume of many CubeSat deployers. This allows the system to be located outside the main CubeSat structure, saving internal space for other payloads. At the same time, it has a big fuel tank that could be customised to fill the “dead space” inside a small satellite.
The TunaTank provides high thrust levels, offering up to 50x more thrust (up to 20 mN at <20W) than typical electric propulsion systems.
While the standard propellant is water, the system can be customised with a water-alcohol mixture to reduce the freezing point to -30 deg C.
The TunaTank is built entirely on flight-proven technology. The system synthesises the core engineering and flight-tested components of our SteamJet TunaCan and Thruster One modules. There are currently 7 of these legacy systems operational in orbit, demonstrating 100% mission success.
The TunaTank is designed to produce no RF interference during operation.
Yes. TunaTank Thruster is designed and manufactured to be 100% ITAR-free. This simplifies the procurement process and international shipping for satellite manufacturers and space agencies globally.
What’s new on TunaTank Thruster
What's next?
- Download TunaTank Thruster Datasheet and CAD model.
- Ask for Price or any other question.
- Need a bigger internal solution for a microsatellite? Check out our Steamjet Thruster One.
- Need to save more space inside a CubeSat? Check out our Steamjet Tunacan Thruster
- If you’re representing an academic or non-profit project, we have a special offer for you! Follow this link to learn more.
- Learn more about SteamJet.