In this blog post, we’ll explore everything from the principles of rocket propulsion to aerospace control research, and examine how mechanical and aerospace engineering plays a role in realizing humanity’s dreams of reaching space.
“4, 3, 2, 1… Launch!” Just hearing this countdown and the word “launch” brings to mind a rocket blasting off into space. At that very moment, neither the pounding of our hearts, nor the cheers expressing our longing for space, nor the excited, raised voices of the live broadcast from the launch site can be heard—the entire world’s attention is focused solely on the instant the rocket blasts off. This demonstrates just how deeply venturing into space has become both an unknown frontier and a matter of unprecedented interest to humanity. And the “rocket,” which serves as the driving force propelling us toward this dream, will play a vital role in future society. So, what is the process behind building these “rockets”? How can a rocket weighing nearly 100 metric tons overcome Earth’s gravity and venture out into the vastness of space?
To solve these problems, the Department of Mechanical and Aerospace Engineering conducts research on various types of jet engines. A jet engine is a device that generates thrust by expelling a jet stream, based on the principle of action and reaction—Newton’s third law of motion. For example, if you release a balloon filled with air into the air without tying it down, the air inside escapes, causing the balloon to drift in various directions—this phenomenon illustrates the principle. To generate the thrust needed to launch a rocket, one can think of it as taking the air thrust generated by a balloon—where air simply escapes—and amplifying it tens of thousands of times through the four stages of a gas turbine engine before launching it from the ground. The four stages that increase thrust are as follows. First, air is drawn into the jet engine through the air intake and passes through the first stage, “compression.” This compressed air is directed to the combustion chamber, where it mixes with fuel and undergoes “combustion.” The explosive “expansion” of the air produced during combustion spins the turbine, generating the rocket’s thrust. This expanded, high-temperature air then passes through the “exhaust and cooling” stage before exiting the engine. Through these four stages—“compression,” “combustion,” “expansion,” and “exhaust and cooling”—the engine generates the force needed to launch a heavy rocket from the ground. Jet engines include not only the basic type mentioned above—the turbojet—but also turbofans, scramjets, water jets, and rockets. The Rocket Propulsion Research Laboratory in the Department of Mechanical and Aerospace Engineering conducts research on jet engines based on the turbojet engine. The laboratory developed the rocket engines for the “Naro-1” and “Naro-2” rockets, which were launched twice in South Korea; unfortunately, both Naro-1 and Naro-2 failed to launch successfully. However, the technological advancements gained from these two attempts bode well for future research.
Furthermore, through long-standing intensive research on optimal injection systems for liquid-fuel rockets, the team has been able to dramatically reduce the volume occupied by rocket engines. Thus, active research is underway in the field of jet engines, which can be considered the core of rocket technology.
While generating the thrust to lift a rocket off the ground is the most critical first step, highly sophisticated technology is also required after liftoff to successfully enter Earth orbit. The Department of Mechanical and Aerospace Engineering is also making significant strides in the field of aerospace control research, which involves conducting error-free flight simulations based on fluid dynamics—including airflow, drag, and the forces a rocket experiences from the air—as well as flight dynamics. Aerospace control research broadly encompasses the “optimal design of intelligent flight control systems,” “flight vehicle survivability analysis” to protect vehicles from meteoroids and other objects while traveling through space, “ultra-precise attitude control research” to measure and optimize a satellite’s natural frequency, and “navigation, guidance, and control system research” for unmanned vehicles capable of operation without a pilot. Through these efforts, the department is laying the groundwork to maximize the maintenance, security, and automation performance of rocket bodies after they are launched by jet engine thrust.
Thus, the Department of Mechanical and Aerospace Engineering is not merely responsible for the design of commonly known fields such as automobiles, shipbuilding, and machine tools—and thus laying the foundation for the secondary industry—but is also conducting research in the rapidly evolving fields of rockets, engines, and control systems in step with the times, thereby making a significant contribution to the technological advancement that South Korea must pursue. Amid the current state of education in South Korea, where there is a widespread aversion to science and engineering, I hope that middle and high school students, as well as the general public, will find a bright vision by reading this introduction. May South Korea, fueled by passion, take off vigorously toward the star of its dreams and reach that destination.
