Plasma actuators are lightweight, simple, and promising. Could they be the future of rocket stability? A look into what’s next for keeping spacecraft steady. 

Image: NASA / Public domain via Wikimedia Commons 

Space. How do we even get there? We get there with rockets, obviously. But how do rockets get there? Well, usually we just use a lot of fuel to torpedo them out of the atmosphere. We all know that. However, what we often overlook is this: how do we keep a rocket stable? 

One can easily underestimate how important stability is for rocketry. Indeed, rockets are inherently unstable. It is in the way they are built. Their center of pressure as it's called is located forward of their center of gravity. To formulate this more simply, most of a rocket's weight is in the back (the fuel storage etc.) but their pressure comes from the front (for example, air pressure). So, what does that mean in essence? In essence, it means that even small instabilities can lead to large catastrophes. If it weren’t for stabilization systems that is. 

Given their unique build, how do we keep rockets stable? The most popular and current systems work like this: an instability occurs because of some torque (force) from outside... a flow of air pressure for example, and now that we have that force, we build a counterforce.  Imagine there is a force acting on a rocket, now we could either pump out more fuel or we could move a large object within the rocket so that the pressure from outside is neutralized. That is how most modern systems work.  

Now that we know how these systems work, you are fully entitled to ask what the problem might be. Why not just continue using these old and usually stable systems? First and foremost: weight. Mechanical components used for stabilization often add unnecessary mass, especially when located inside the rocket. The same goes for mechanical systems outside of the rocket, such as fins which have gotten increasingly popular with space jets. Secondly, automatic systems. To move parts, we need energy, especially in automatic systems. Oftentimes we use electric systems that automatically detect instabilities and try to send signals to the mechanical stabilization systems. That can be problematic. Not only does this cause heavy attrition on the system over time, but systems at times send signals that make no mechanical sense. Imagine your brain sending a signal to your arm to bend 360 degrees. Not possible, that leads to failure. Otherwise, signals can get distorted and lead to flutter effects, which is a kind of vibrating, unstable shaking that can damage or destroy parts of the rocket. Imagine your brain sending a signal to your hand, but it gets there too late, so your hand tries to overcorrect again and again and starts vibrating. These are all serious problems with our current systems. 

Photo of a plasma actuator experiment in the MARHy wind tunnel by Sandra C., licensed under CC BY-SA 4.0 via Wikimedia Commons. 

Now, let's take a small detour and explain what so-called dialectic barrier discharge (DBD) plasma actuators really are. This technology, in its essence, is very simple. Actuators usually consist of two asymmetrically arranged electrodes (typically copper foil) separated by a dielectric layer (Kapton tape, quartz, Teflon, glass etc.) without requiring any moving parts. Through electric current they can charge the air around them and create plasma. These plasma particles move around and generate a drift of air also known as an ‘ionic wind’. That wind can reduce forces applied from outside pressure of any object. Very simply put, this is how a plasma actuator works. 

Why might this be better than our usual mechanical systems? Well, this technology doesn’t have many of the disadvantages that our current systems suffer under. For one, since plasma actuators are two separated strips of metal, they weigh almost nothing. They do not move and thus do not suffer under mechanical attrition. They respond more quickly to signals, but do not cause instabilities or flutter, by selecting a quasi-steady power frequency of 3kHz. Without going into too much detail, plasma actuators are lighter, quicker and more precise than our current systems. 

Naturally, the question arises: if plasma actuators are so great, why aren’t they everywhere? This is an excellent question and sadly, as so often, plasma actuators have notable limitations. For one, the ‘ionic wind’ is simply not strong enough yet to properly stabilize, especially on rockets; oftentimes, their power supply is wasted on heat or radiative losses. The actuator still consumes way too much energy to be in wide use; it is still difficult to scale plasma actuators as they can cause uneven plasma distribution and general distortion. These are some of the reasons why plasma actuators are not in wide use (yet). 

However, and this should be noted, plasma actuators have been gaining ground recently. Patel, Cain & Nelson (2012) introduced stronger plasma actuator designs which work in supersonic airflows. Opaits (2012) developed a system which can reduce power consumption and stabilise plasma actuators on a larger scale. Recently, Viguera, Sasaki & Nonomura (2024) developed a new technique of plasma actuator energy usage that cuts power costs by up to 15%. While plasma actuators are yet to become a replacement for current methods, there is a clear trend towards plasma stabilization.  

This leaves us with one question that may soon shift from theoretical to practical: Could this tiny plasma device reshape the way we launch ourselves into the stars?  

Published 28th of July, 2025

Michael Alexander Volkonsky is a 21-year-old economics student at Lund University, a science communicator exploring interdisciplinary issues, and an advocate for open debate and critical thinking.