A CubeSat’s lifespan depends not only on how much fuel it carries but also on the type of thruster it uses. Different CubeSat propulsion technologies affect mission duration in different ways. Because they vary in efficiency, compactness, and reliability.
Let’s dive into these technologies and compare the main types of thrusters based on four criteria:
- efficiency – thrust produced per unit of fuel,
- compactness – space they occupy on a small satellite,
- reliability – consistency in performance over time,
- impact on mission duration – how each factor ultimately affects how long the satellite will operate.
1. Cold Gas Thrusters
Cold gas thrusters are not the most efficient ones. They produce very little thrust per unit of propellant. As a result, the fuel tank takes up a lot of space on a small satellite. Hence, compactness is affected negatively. At the same time, they are highly reliable. Cold gas thrusters have a very simple design, which makes them reliable, and they rarely malfunction over time. Ultimately, however, it is precisely this low efficiency and large fuel volume that become the main problem. The propellant supply is depleted quickly, which leads to shorter mission duration.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
Cold Gas Thrusters | ~ 40 – 80 seconds | 1 mN до 100 mN |
2. Chemical (Monopropellant) Thrusters
Monopropellant thrusters provide high thrust. This characteristic makes them excellent for satellite manoeuvres. However, they do have certain disadvantages. Namely, the propellant is toxic and requires complex storage. As a result, it complicates the design and reduces compactness. Over time, the thruster components degrade, reducing reliability. It is this degradation that poses the main limitation. Specifically, this type of thruster doesn’t suit long-term missions.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
Chemical (Monopropellant) Thrusters | ~ 200 – 230 seconds | 20 mN to 1 N+ |
3. Electric Propulsion (Ion/Hall Effect)
Hall effect thrusters are highly efficient and have a long service life. On the other hand, they are large and consume a lot of energy. This propulsion system is difficult to integrate into a small CubeSat.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
Electric Propulsion (Ion/Hall Effect) | ~ 1500 – 3500 seconds | 0.1 mN to 30 mN |
4. Resistojet/Water-Based Propulsion
These CubeSat propulsion systems are safe because of non-toxic propellant (water). They have moderate efficiency and are easy to store and refuel. All of these factors directly contribute to extending mission duration without the risk of degradation.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
Resistojet/Water-Based Propulsion | ~ 80 – 150 seconds | 5 mN to 50 mN |
5. Green Monopropellant Systems
It is a safer alternative to toxic propellant. This type of CubeSat propulsion system combines sufficient thrust with safety in use. However, the main downside is that the technology is still relatively new and has not been thoroughly tested in practice. Hence, there is not enough proof of how well it is suited for long-duration missions.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
Green Monopropellant Systems | ~ 200 – 255 seconds | 30 mN до 1 000 mN |
6. Compact High-Thrust Solutions (SteamJet TunaCan and TunaTank form factors)
This solution incorporates the best features of previous ones. The Compact CubeSat propulsion system resolves the main trade-off faced by all other types of engines. Namely, the necessity to choose between good thrust and compact size. These thrusters provide sufficient thrust while taking up little space on the platform. Because every cubic centimetre of the satellite is used as efficiently as possible, the mission’s lifespan is directly extended.
Range of specific impulse (Isp) | Thrust Range | |
|---|---|---|
SteamJet TunaCan Thruster | 172 seconds | 5 – 20 mN |
SteamJet TunaTank Thruster | 172 seconds | 5 – 20 mN |
SteamJet Thruster One | 172 seconds | 5 – 20 mN |
Source: SteamJet official website
Choosing a CubeSat propulsion system always comes down to a trade-off: you have to choose between thrust, compactness, and reliability. There is no ideal solution that offers everything at once. But a new generation of technologies, such as water-based propulsion systems and compact, high-thrust solutions, is gradually shifting this balance for the better. They allow satellites to operate longer without losing efficiency.
About SteamJet Space Systems
SteamJet Space Systems is a leading UK-based provider of high-performance satellite propulsion solutions. We specialise in water-based propulsion solutions designed specifically for CubeSats and Small Satellites (SmallSats), prioritising operational safety and rapid launch integration.
By pioneering the use of green propellants and intelligent thermal engineering, SteamJet enables complex LEO (Low Earth Orbit) manoeuvres — including orbital maintenance, collision avoidance, and de-orbiting — without the risks associated with toxic hydrazine or high-pressure cold-gas systems, thereby advancing green propulsion for space missions.
Steamjet Propulsion Technology
Our modular systems are engineered for seamless integration and maximum safety compliance:
Steamjet TunaCan Thruster: A compact, high-efficiency solution for 1U-3U CubeSats.
Steamjet TunaTank Thruster: A safe, high-performance electrothermal propulsion system.
Steamjet Thruster One: Scalable propulsion for larger SmallSat constellations.
Discover how SteamJet’s sustainable space propulsion innovations are providing the safety and reliability required for the next generation of crewed and robotic missions. Contact our engineering team for technical specifications and ICDs.