Electric Propulsion Systems for CubeSat Missions:

Small Satellite Capability Expansion

Afshin Mithwani,

SHAPE American High School - Department of Defense

Abstract

The recent surge in the number of CubeSat missions has completely transformed the cosmic

domain by providing affordable scientific, commercial, and educational applications in space. The limited

mass, volume, and power resources in CubeSat platforms pose a substantial restriction on propulsion

systems in space. The following study will investigate the three most prominent electric propulsion types

in the realm of space propulsion for CubeSat applications: ion thrusters, Hall effect thrusters, and pulsed

plasma thrusters. The study will analyze and compare the efficiency and power needs of each propulsion

system in terms of scalability and suitability for space applications based on aerospace studies. The study

will also investigate the effect of propulsion systems on orbital maneuverability and mission lifetime.

Although electric propulsion has greatly improved the operational limits for CubeSat space missions,

many problems related to power availability and long-term reliability still persist.

Introduction

CubeSats are game-changers in the modern aerospace scene, making it easier to get in orbit, and

speeding up the rate of design and operations for missions. What began as simple, often passive

experiments quickly evolved into small satellites performing more and more challenging tasks like

maintaining an orbit, flying in tight formations, and even venturing beyond Earth for interplanetary ideas.

With increasing aspirations comes increasing demand for onboard propulsion that fits within tight size

and power budgets.

The field of small-satellite propulsion is moving fast, and there's no best architecture universally

agreed on. In perspective of the established studies, this review gives an insight into what works, what

doesn't, and how in general the propulsion strategies for CubeSats are set up.

This begs the question; how well do existing electric propulsion options handle unique

operational and physical constraints relative to CubeSat missions?

Discussion

Propulsion Constraints in CubeSat Design

Unlike conventional spacecraft, CubeSats are subject to standardized sizes measured in units of

10 × 10 × 10 cm. As a result of these standardized sizes, there are strict constraints on the mass, volume,

and power of the propulsion system. According to Mueller et al. (2010), the propulsion system will

compete with the payload and the power subsystems for onboard system resources, making system

integration a critical design challenge.

The power available has been shown to be the biggest limiting factor in the propulsion of

CubeSat missions. Solar arrays and battery systems generally supply only a few watts of continuous

power, thus making it impossible to use high-thrust propulsion systems. This further makes the use of

propulsion systems that prioritize efficiency over raw thrust a necessity.

Ion Thrusters for Precision Maneuvering

Ion engines are being researched extensively for CubeSat missions because of their high

specific impulse and efficient use of propellant. Ion engines produce propulsion by accelerating

ions in electrostatic fields, leading to very low thrust levels, but activated for an extended period

of time. Research by Goebel & Katz (2008) shows that ion engines are most suitable for orbital

maneuvers.

The writers also note that ion thrusters are not very appropriate when it comes to fast

maneuvers. Moreover, their thrust to power ratio also restricts their use when there are

requirements of slow maneuvers. Additionally, concerns regarding grid erosion and system

lifetime remain significant, particularly for long-duration missions in harsh space environments.

Hall-Effect Thrusters and Power Trade-Offs

The Hall-effect thrusters are superior in thrust density to the ion thrusters, and thus they

are incorporated into CubeSats, which are expecting to have significant orbital maneuvers. The

principle of these thrusters is to utilize the magnetic fields for the trapping of electrons,

propellant being ionized and ions being accelerated to create thrust. Results of Szabo and Pote

(2014) lead to the conclusion that the small-scale Hall thrusters can outdo ion systems with

regard to performance significantly.

Despite these advantages, Hall-effect thrusters are still the major contributors to the

power budget of these small CubeSats. In addition, their greater power consumption means that

larger solar arrays or high-tech power management systems have to be installed, which makes

the system more complex. Consequently, there is still no agreement in the literature as to

whether Hall thrusters are a practical solution for nanosatellites or whether they are just suitable

for larger small-satellite platforms.

Pulsed Plasma Thrusters and System Simplicity

Pulsed plasma thrusters (PPTs) are one of the oldest propulsion technologies already

employed for CubeSat missions. The thrust is produced by the electrical discharges of a few

pulses, which vaporize then solidify propellant material. However, despite their lower efficiency

when compared to ion or Hall thrusters, PPTs hold a great appeal for educational and

experimental missions due to their simplicity in engineering and low power requirements.

Research by Burton and Turchi (1998) pointed out the strength of PPTs in reliability

during short missions, but at the same time, the low total impulse and the limited controllability

of the devices reduced their areas of application in advanced mission scopes. As a result, typical

literature places PPTs as a practical entry-level propulsion solution rather than a long-term

scalable technology.

System-Level Impacts and Mission Integration

Across the literature, propulsion system selection is shown to directly influence CubeSat

mission architecture. Electric propulsion makes it possible to extend the life of the missions,

avoid collisions, and even manage the constellation, but it also leads to the need for more

complex power distribution, thermal management and control algorithms. Lev et al. (2019) argue

that propulsion should be considered as a system-level design parameter rather than as an

isolated subsystem.

There are different opinions regarding the capability of current CubeSat propulsion

technologies for deep-space missions. Some studies argue that there are still limitations in the

field of power generation and storage before the technologies can be actually used for deep-space

missions. On the other hand, there are some studies that report successful demonstrations.

Conclusion

This literature review demonstrates that electric propulsion technologies have fundamentally

expanded the capabilities of CubeSat missions while introducing new design challenges. Ion thrusters,

Hall-effect thrusters, and pulsed plasma thrusters each offer distinct advantages and limitations, with

power availability and system integration emerging as recurring constraints.

Future researchers should direct their investigations towards power efficiency enhancement,

propulsion system lifetime extension, and reliable integration protocols creation for small satellites. The

overcoming of these problems will be necessary to allow even more complicated CubeSat missions and to

further the small satellites' contribution in aerospace exploration.

References

1. Mueller, J., Hofer, R., & Ziemer, J. (2010). Survey of propulsion technologies applicable to

CubeSats. Journal of Propulsion and Power, 26(6), 1150–1161.

2. Goebel, D. M., & Katz, I. (2008). Fundamentals of Electric Propulsion. Jet Propulsion

Laboratory.

3. Szabo, J., & Pote, B. (2014). Low-power Hall thrusters for small spacecraft. AIAA Journal,

52(11), 2564–2576.

4. Burton, R. L., & Turchi, P. J. (1998). Pulsed plasma thruster. Journal of Propulsion and Power,

14(5), 716–735.

5. Lev, D., Myers, R., Lemmer, K., Kolbeck, J., Keidar, M., & Polzin, K. (2019). The technological

and commercial expansion of electric propulsion. Acta Astronautica, 159, 213–227.