In this blog post, we’ll start with humanity’s dream of flying through the skies and explore the structure and propulsion systems of rockets, Kspace’s rocket development plans, and the various possibilities that small rockets can offer.
Humanity’s Dream of Going Beyond the Skies and Into Space
Long ago, the Wright brothers flew the world’s first airplane. Humans have long harbored a desire to fly through the vast skies, and that dream became a reality when American Charles Lindbergh successfully completed an ultra-long-distance flight across the Atlantic. Now that even ordinary people can fly through the skies on commercial airliners if they wish, that aspiration has evolved into a dream of venturing into space. Space powers such as the United States and Russia have developed rockets to launch humans into space. While South Korea has reached a world-class level in terms of economic scale and overall technological capabilities, there is still much room for growth in the aerospace industry. Now is the time for South Korea to actively invest in rocket development.
We are Kspace, a rocket development team formed by students from SNU, KAIST, and GIST who share a passion for building rockets that can reach space. Our goal is to develop a two-stage rocket capable of carrying cargo and living organisms into space by first developing and launching solid-fuel and liquid-fuel rockets separately, and then combining the two. Since we began our activities, the development of the solid-fuel rocket has reached the final stages prior to launch, while the liquid-fuel rocket still requires the fabrication of the engine and nozzle.
A rocket is broadly divided into two main components: the engine and other structural elements. The engine consists of propellant, fuel tanks, a nozzle, and a turbine, while the other structural elements include attitude control systems, thrust vector control systems, and automatic navigation systems. Kspace’s university chapters are分工 to manufacture these components, and our SNU chapter is responsible for the engine section. To explain our engine development plan, I will briefly describe the basic structure of a rocket engine.
How are rocket propellants classified?
First, let me explain the propellants. Rocket propellants are broadly classified into two types: solid propellants and liquid propellants. Solid propellants are created by mixing an oxidizer with a liquid propellant and then solidifying the mixture chemically; they can generate significant thrust with just a small amount and a simple structure. However, they have the disadvantage of being difficult to control because combustion cannot be stopped once ignited, and the rocket must be built to withstand the high temperatures and pressures generated during combustion. We will be using solid fuel that we produced ourselves. This fuel consists of white, water-soluble powder particles that use ammonia as the primary fuel and perchlorate as the primary oxidizer. We synthesized this fuel ourselves and have secured a sufficient quantity to launch the rocket.
Second, liquid-fuel rockets store the fuel and oxidizer in separate tanks and mix them in a separate combustion chamber during combustion. Although the structure is complex, it offers the advantages of controllable combustion and ease of manipulating thrust and direction. We will use an oxidizer called NTO in our liquid-fuel rocket. It has the advantages of being storable at room temperature, having a simple ignition method, and—unlike other fuels—not causing corrosion in the tanks. Since it is difficult for us to synthesize this fuel and oxidizer ourselves, we will purchase them for use.
How are the fuel tank, nozzle, and turbine configured?
Next, I will explain the fuel tank, nozzle, and turbine.
The reason we are explaining the rest of the engine’s structure all at once is that, although their shapes differ, they will be made of the same material. This differs from conventional engines, where the tank and nozzle are manufactured separately. Since we are using a non-corrosive fuel, the need for the tank to have high corrosion resistance is reduced; furthermore, because the rocket is small, the tank also needed to withstand the high temperatures and pressures of the nozzle. Therefore, we needed a material that was resistant to high temperatures and pressures yet easy to machine. The method we chose was to create a mold out of graphite and then plate the exterior. This is because graphite can be machined relatively easily using a 3D printer, and it has the property of becoming stronger in high-temperature, high-pressure environments. For solid-fuel rockets, we will manufacture them by tightly wrapping graphite with nanocarbon fibers, while for liquid-fuel rockets, we will plate the graphite surface with nickel. The nanocarbon fibers and nickel will serve as the primary barrier protecting the graphite from high temperatures and pressure, while also preventing contact between the graphite and oxygen. We are currently purchasing nano-carbon fibers and wrapping them around the graphite, and we plan to purchase specialized plating equipment to use with nickel in order to improve the quality of the finish.
Now I will explain the overall structure of the rocket. The solid-fuel rocket has a very simple design: the nozzle is simply attached directly below the fuel storage tank. However, the liquid-fuel rocket is a bit more complex. First, there are two storage tanks—one for fuel and one for oxidizer—and the combustion chamber is also divided into two parts. One is the preliminary combustion chamber, and the other is the main combustion chamber. The preliminary combustion chamber can be described as a gas generator, while the main combustion chamber is the engine. Since the purpose of the preliminary combustion chamber is to produce high-temperature oxidizing gas, it is also called a gas generator. A large amount of oxidizer and a small amount of fuel are fed into the pre-combustion chamber, leaving some oxidizer unburned. This remaining oxidizer mixes with the high-temperature combustion gases produced when the fuel burns and is ejected toward the main combustion chamber. The main combustion chamber receives a much larger amount of fuel than was fed into the pre-combustion chamber, which oxidizes all of the remaining oxidizer. The temperature at this stage is much higher than in the pre-combustion chamber, and the resulting high-temperature, high-pressure combustion gases are ejected through the nozzle, providing thrust to the rocket.
What do the rockets developed by Kspace look like?
We have named the solid-fuel rocket and liquid-fuel rocket we are developing “Lumière G” and “Lumière N,” respectively. Lumière G is designed with a total mass of approximately 4 kg, and Lumière N with a total mass of approximately 69 kg; we plan to launch the solid-fuel and liquid-fuel rockets, respectively. Prior to that, we will conduct necessary combustion tests and other trials using the KAIST rocket laboratory we have leased, and we have selected Songjeong Beach in Busan as the launch site. A launch pad manufactured at the GIST branch will be installed in the shallow coastal waters, and two launches—one vertical and one horizontal—will be conducted from the launch pad. The vertical launch is expected to reach beyond the stratosphere into the thermosphere, while the horizontal launch is expected to cover the distance from Busan to Tsushima Island.
After completing these two rocket launches, we will develop “Lumière D,” a two-stage rocket combining the two rockets. The “Lumière D” will be constructed with a liquid-fueled rocket at its core, surrounded by six small solid-fuel rockets arranged in a square formation. The goal is to make it capable of carrying various cargo or living organisms—such as hamsters—weighing up to 2 kg and, upon launch, reaching the orbit of the International Space Station.
If the Lumière D is successful, it will mark the world’s first successful development of a small, inexpensive, convenient, and reusable rocket.
This rocket will have many potential applications in the future. When universities or corporate research labs need to conduct experiments in space—which until now required paying billions of won to launch from foreign countries—our rocket will make such experiments possible at a relatively low cost of around 100 to 200 million won. Furthermore, if we succeed in stabilizing the small rocket, it could be utilized as a “cargo taxi” capable of delivering cargo from Seoul to Busan in just 10 minutes. As you can see, our research holds limitless potential.
How should South Korea’s aerospace technology develop?
In the past, there was a day when the Nobel Prize in Physics was announced. However, even then, no Korean scientist was among the winners. What was the reason for this? It was precisely because our foundation in basic science was not strong enough compared to applied science. Aerospace technologies, such as rockets, require significant resources and time in the early stages, but once the foundational technologies are established, they will serve as a driving force to make South Korea even more prosperous and powerful. We hope you will lend your support to our research, which holds limitless potential.
