Propelling the Future: A Look at CubeSat Propulsion Technologies

Introduction

CubeSats have revolutionized space exploration by offering a cost-effective and modular platform for scientific research, Earth observation, and technology demonstrations. However, as mission requirements grow more complex—ranging from orbital maneuvering to deep-space exploration—the need for efficient propulsion systems has become critical.

As CubeSats revolutionize access to space with their compact design, cost-effectiveness, and modularity, one area remains a significant bottleneck in their capabilities—propulsion. While CubeSats have become critical assets for Earth observation, scientific experiments, and interplanetary exploration, their ability to maneuver in space has historically been limited by their size and power constraints. However, recent advancements in miniaturized propulsion technologies are changing this paradigm, enabling CubeSats to perform more complex missions, including orbit adjustments, formation flying, and even deep space navigation.

In this article, we’ll explore the latest advancements in CubeSat propulsion technologies, their applications, and how they’re shaping the future of small satellites.

Why CubeSat Propulsion Matters

The integration of propulsion systems into CubeSats dramatically enhances their functionality. These systems allow for key maneuvers such as attitude control, station-keeping, collision avoidance, deorbiting, and trajectory changes. Without propulsion, CubeSats are largely passive, limited to the orbits into which they are deployed. By enabling active mobility, propulsion transforms CubeSats from static platforms into agile instruments capable of performing a wide array of dynamic missions.

Traditional CubeSats were initially designed as passive satellites, relying on natural orbital decay or minimal station-keeping. But today’s missions demand advanced propulsion for various applications.

One key need is orbit maintenance, where propulsion systems counteract atmospheric drag to extend satellite lifespans. Another critical application is formation flying, enabling coordinated maneuvers in satellite swarms for distributed sensing or communication networks.

More ambitious missions, such as interplanetary travel, require propulsion systems capable of escaping Earth’s gravity and navigating deep space. Additionally, debris mitigation is becoming increasingly important, with propulsion enabling controlled deorbiting to prevent space junk accumulation.

To meet these challenges, engineers have developed a variety of propulsion systems tailored for CubeSats.

Types of CubeSat Propulsion Systems

CubeSat propulsion systems are broadly classified based on the energy source and mechanism used to generate thrust:

1. Kinetic Propulsion:

Kinetic Propulsion encompasses systems such as cold gas and warm gas thrusters, which rely on the expansion of stored pressurized gases to generate thrust. These propulsion systems are mechanically simple, compact, and highly reliable, making them attractive for missions where robustness and low complexity are priorities. However, this simplicity comes at the cost of performance, as they generally provide a lower specific impulse compared to more advanced propulsion technologies.

Cold Gas Thrusters are the most straightforward form, expelling inert gases like nitrogen through a nozzle to produce thrust. Their biggest advantages are reliability, safety, and minimal risk of combustion, which makes them ideal for low-risk missions, student satellites, or spacecraft requiring precise but limited maneuvers. Despite these benefits, their efficiency is notably low, with specific impulse values typically ranging between 50 and 80 seconds. This severely restricts their delta-V budget, confining their role to minor orbit corrections and attitude control rather than major orbital transfers or deep-space maneuvers.

As a result, while kinetic propulsion systems remain valuable for small satellites and missions emphasizing safety and simplicity, they are increasingly supplemented or replaced by higher-performance electric or chemical systems for applications demanding greater maneuverability and mission flexibility.

2. Chemical Propulsion (Monopropellant & Bipropellant)

Chemical propulsion remains one of the most powerful and time-tested methods for satellite maneuvering, delivering significantly higher thrust compared to electric or cold gas alternatives. By employing solid, liquid, or hybrid fuels, these systems enable rapid orbital transfers, high-energy maneuvers, and mission flexibility that smaller propulsion systems cannot easily match. With advancements in green propellants, chemical propulsion is becoming safer and more environmentally sustainable, broadening its appeal for future missions.

Traditional systems often rely on hydrazine, a highly efficient yet toxic monopropellant. However, new formulations such as AF-M315E and LMP-103S are emerging as viable “green” replacements, offering comparable or better performance while reducing handling risks and regulatory burdens. This shift not only improves safety for ground crews but also lowers operational costs, making chemical propulsion more accessible for commercial and government programs alike.

For CubeSats and small spacecraft requiring robust maneuverability, chemical propulsion offers a compelling option, particularly for missions demanding high delta-V or quick response capabilities. Whether for constellation repositioning, debris avoidance, or deep-space operations, the ability to generate strong thrust in short bursts gives these systems a distinct advantage over purely electric alternatives.

Nevertheless, challenges remain. Handling and storage of chemical propellants—especially toxic ones—require specialized facilities, training, and compliance with strict international regulations. This adds complexity and cost, especially for smaller satellite operators. Even with green propellant advancements, careful engineering is necessary to balance system mass, safety, and efficiency. Despite these hurdles, chemical propulsion continues to play a critical role in enabling demanding space missions that cannot compromise on thrust or agility.

3. Electric Propulsion (Ion & Plasma Thrusters)

These systems, such as ion and Hall-effect thrusters, use electrical energy to accelerate ions or plasma. They are highly efficient and suitable for long-duration missions, though they typically generate lower thrust.

Electric propulsion systems, such as electrospray ion thrusters, pulsed plasma thrusters (PPTs), and Hall-effect thrusters (HETs), use electric fields to accelerate ions or plasma for thrust. These systems boast extremely high specific impulse, often between 1,000 to 3,000 seconds, making them highly fuel-efficient.

The trade-off is their low thrust output and high power requirements, which can be a limitation for small satellites with constrained energy budgets. Nevertheless, they are ideal for deep-space missions and long-duration station-keeping where efficiency outweighs the need for rapid acceleration.

Electrospray thrusters are emerging as a revolutionary propulsion technology for small satellites, offering precise, efficient, and scalable performance in an ultra-compact form. Unlike traditional chemical propulsion, which consumes large amounts of fuel, or bulky electric propulsion systems, electrospray thrusters use ionized liquid propellants to generate finely controlled thrust. This enables satellites to maneuver, maintain orbits, and extend their operational lifetimes with minimal mass and power requirements.

Their advantages make them particularly well-suited for the rapidly growing small satellite market. From constellation management in low Earth orbit to deep-space exploration missions, electrospray thrusters provide the high delta-V, low-power propulsion needed to expand mission possibilities. Demonstrations such as NASA’s Lunar IceCube have already shown their potential in real-world applications, highlighting their reliability and precision in challenging environments.

Despite this promise, challenges remain. Scaling electrospray technology to support higher thrust levels for larger spacecraft requires careful engineering, while issues such as electrode erosion, clogging, and long-term durability must still be addressed. Beyond technical hurdles, the industry must also tackle regulatory and standardization challenges to ensure safe, interoperable deployment as more satellites adopt this propulsion method.

Looking ahead, ongoing research in materials science, nanotechnology, and emitter design is steadily overcoming these obstacles. With increasing investment and growing adoption by commercial and government operators, electrospray thrusters are on track to become a cornerstone of next-generation space propulsion. By enabling efficient, precise, and sustainable mobility for small satellites, they are helping shape a new era of space exploration and commerce.

4. Water-Based Propulsion

Water-based propulsion represents an innovative and sustainable approach to spacecraft maneuvering, relying on the electrolysis of water to produce hydrogen and oxygen, which are then combusted for thrust. Its greatest strength lies in safety: water is non-toxic, stable, and easy to store compared to traditional chemical propellants. These attributes make it especially attractive for academic missions, small satellite operators, and future exploration architectures where simplicity and reliability are key.

Beyond safety, water-based systems open exciting opportunities for in-situ resource utilization (ISRU). Since water is abundant on the Moon, asteroids, and Mars, spacecraft could potentially refuel directly from local resources, reducing dependency on Earth-based launches. This capability positions water propulsion as a stepping-stone technology for sustainable deep-space exploration and interplanetary logistics.

The primary trade-off comes from water’s relatively low energy density compared to conventional fuels, limiting the thrust and delta-V that such systems can provide. As a result, they are less suited for missions requiring rapid orbital changes or high-power maneuvers. Instead, they excel in applications prioritizing safety, longevity, and cost-effectiveness over raw performance.

Despite these limitations, water-based propulsion is gaining traction as a practical option for CubeSats, university-led missions, and demonstration projects. With ongoing research and improvements in electrolysis efficiency and combustion systems, water could become a cornerstone fuel for the next generation of small spacecraft, balancing sustainability with mission utility.

5. Non-Propellant Systems:

Techniques like solar sails, electrodynamic tethers, and photonic propulsion use environmental forces instead of onboard propellant, offering long-term, sustainable mobility options.

Solar Sails & Electrodynamic Tethers

Solar sails and electrodynamic tethers represent propulsion technologies that bypass the need for traditional propellants, offering unique advantages for long-duration missions. Solar sails harness the momentum of photons from sunlight to generate thrust, while electrodynamic tethers interact with Earth’s magnetic field to create propulsive or drag forces. Since neither system consumes onboard fuel, they provide the potential for theoretically infinite operational lifetimes, making them attractive for missions where sustainability and endurance are key.

The greatest limitation of these systems lies in their low thrust levels. Solar sails require expansive, lightweight reflective surfaces to achieve meaningful acceleration, while electrodynamic tethers demand long conductive structures and robust power management. As a result, both approaches are more suited to applications where gradual trajectory adjustments are acceptable, rather than missions requiring rapid orbital maneuvers or high delta-V performance.

Despite these challenges, the applications are compelling. Solar sails are ideal for deep-space missions, such as station-keeping at non-traditional orbits or even interstellar exploration concepts, where long-term propulsion without refueling is advantageous. Electrodynamic tethers, on the other hand, are especially promising for passive deorbiting of satellites, enabling cost-effective compliance with space debris mitigation guidelines.

Together, these technologies underscore the growing emphasis on sustainable, fuel-free propulsion. While they may not replace high-thrust systems for time-sensitive maneuvers, their ability to extend mission lifetimes and reduce reliance on expendable propellants makes them an important part of the propulsion toolkit for the future of space exploration and orbital management.

Emerging Technologies

Emerging propulsion technologies are redefining how spacecraft maneuver, optimize efficiency, and extend mission lifespans. From miniaturized thrusters for CubeSats to futuristic laser propulsion and advanced 3D-printed designs, these innovations promise to make space travel lighter, faster, and more sustainable.

Real-World Applications and Milestones

Numerous CubeSat missions have demonstrated successful in-space propulsion. For instance, the CanX-4 and CanX-5 missions showcased formation flying using cold gas thrusters, while NASA’s MarCO CubeSats demonstrated trajectory correction maneuvers en route to Mars using micro-propulsion systems. Additive manufacturing is also playing a role, with 3D-printed propulsion modules offering lightweight, customized solutions for tight CubeSat volumes.

Moreover, environmentally conscious propulsion systems—such as water-based steam thrusters or resistojets—are gaining attention for their non-toxic and low-pressure designs, aligning with the growing push for greener space technologies.

Challenges & Future Outlook

Despite rapid advancements, CubeSat propulsion still faces several hurdles. Power constraints remain a major issue, particularly for electric propulsion systems that require high wattage. Regulatory barriers also complicate the use of certain propellants, such as hydrazine, pushing research toward greener alternatives.

Miniaturization is another challenge, as scaling down thrusters without sacrificing efficiency is difficult. However, innovations like modular propulsion systems, improved energy storage, and novel propellants are steadily overcoming these obstacles.

Looking ahead, CubeSats equipped with advanced propulsion will undertake increasingly ambitious missions—from lunar exploration to asteroid mining. The continued evolution of these technologies will play a pivotal role in democratizing space access and enabling new scientific discoveries.

Looking Ahead

As CubeSat missions grow in ambition and complexity, the demand for sophisticated, reliable propulsion solutions will continue to rise. Future trends include hybrid propulsion systems, multi-modal thrusters capable of switching between chemical and electric modes, and AI-optimized thrust control for autonomous maneuvering. Ongoing research is also exploring the use of in-situ resources—like asteroid regolith or lunar ice—for propulsion, potentially supporting long-term exploration missions.

Conclusion

In conclusion, propulsion technologies are no longer an afterthought in CubeSat design—they’re becoming central to unlocking their full potential. With ongoing advancements in miniaturization, materials science, and green propellants, CubeSats are poised to expand their reach deeper into the cosmos, propelled by innovation as much as by fuel.

CubeSat propulsion has evolved from an afterthought to a cornerstone of modern small satellite missions. As technology progresses, we can expect even more efficient, compact, and versatile propulsion systems that push the boundaries of what CubeSats can achieve.

Further Reading:

• NASA’s CubeQuest Challenge
• The Rise of Electric Propulsion for SmallSats (AIAA Papers)
• Mars Cube One (MarCO) Mission Insights