They are relatively inexpensive to build and launch and can be used to perform various missions, including Earth observation, technology demonstration, and scientific research. One of the key questions that CubeSat developers often ask is whether their satellite requires a propulsion system.

Types of CubeSats propulsion systems:

Two main types of propulsion systems are used on CubeSats: chemical propulsion systems and electric propulsion systems.

• Chemical propulsion systems use a chemical reaction to produce thrust. The most common type of chemical propulsion system used on CubeSats is a cold gas thruster. Cold gas thrusters are relatively simple and inexpensive, but they are not very efficient.

• Electric propulsion systems use electricity to accelerate propellant ions. Electric propulsion systems are more efficient than chemical propulsion systems but are also more complex and expensive.

The Role of the propulsion system in CubeSat missions:

A propulsion system allows a satellite to move around in orbit, which can be useful for a variety of purposes, such as:

• Changing orbit altitude: This can be useful for adjusting the satellite's field of view or to avoid collisions with other objects in orbit.
• Changing orbital inclination: This can be useful for adjusting the satellite's coverage area or to match the inclination of other satellites in a constellation.
• Deorbiting the satellite: At the end of its mission, this is important to prevent it from becoming space debris.

However, propulsion systems can add complexity, cost, and mass to a CubeSat. Therefore, it is important to carefully consider whether a propulsion system is necessary for a particular mission.

When does a CubeSat need a propulsion system?

There are a few cases where a CubeSat may need a propulsion system:

• If the CubeSat needs to perform a complex orbital maneuver, a CubeSat designed to rendezvous with another spacecraft or to deploy into a specific orbit will require a propulsion system.
• If the CubeSat needs to maintain its orbit for a long time, CubeSats naturally deorbit over time due to atmospheric drag. A propulsion system can be used to periodically boost the CubeSat's orbit to keep it in place.
• If the CubeSat needs to operate in a high-radiation environment, Radiation can degrade the performance of electronic components over time. A propulsion system can move the CubeSat to a lower-radiation orbit to extend its lifespan.

When does a CubeSat not need a propulsion system?

There are also many cases where a CubeSat may not need a propulsion system:

• If the CubeSat is designed for a short mission, CubeSats can typically stay in orbit for several months without a propulsion system. If the CubeSat is only intended to operate for a short period, then a propulsion system may not be necessary.
• If the CubeSat is on a low-cost mission, Propulsion systems can add significant cost to a CubeSat mission. If the CubeSat is on a tight budget, it may be necessary to omit the propulsion system.
• If the CubeSat is designed for a simple mission, CubeSats can perform various missions without a propulsion system. For example, a CubeSat intended to take images of the Earth does not need a propulsion system.

While not every CubeSat mission necessitates a propulsion system, their inclusion significantly expands mission possibilities. Understanding the benefits and constraints of propulsion systems is crucial in designing a successful CubeSat mission.

References

NanoAvionics. (n.d.). CubeSat Propulsion System EPSS. [online] Available at: https://nanoavionics.com/cubesat-components/cubesat-propulsion-system-epss/.

‌ Bomani, B. M. M. (2021). CubeSat Technology Past and Present: Current State-of-the-Art Survey. http://www.sti.nasa.gov