1. Name of Thrones

The engine’s name was inspired by the largest and most powerful dragon in the “Song of Ice and Fire” book series and HBO television series “Game of Thrones.” Balerion, also called the Black Dread, was ridden by Targaryen kings and helped forge the iconic Iron Throne.

2. The most powerful 3-D-printed, student-built engine

Balerion can produce 2,250 pounds of thrust — equal to a little more than one ton, or about one black rhinoceros — making it the most powerful student-built, 3-D-printed rocket engine in the world. This is also the first student group to use two engines in their flight vehicle, resulting in one
extremely powerful rocket. Two Balerion engines means 4,500 pounds of thrust, launching their rocket about 20,000 feet into the air.

3. Manufactured completely in-house

Unlike other student-made, 3-D-printed rocket engines, Balerion is made completely in-house at USC. The parts are printed at USC’s Center for Advanced Manufacturing, and the finishing touches, which includes threading, sealing and confirming critical dimensions, are done by the university’s machine shop. The engine will remain on campus during the entire manufacturing and building process until it’s ready for testing, which will occur at USC, at UC
San Diego and in Southern California’s Mojave Desert.

4. Materials

The printed engine parts are made of Inconel 718, a high-strength, nickel-based superalloy capable of withstanding high temperatures, stresses and highly oxidizing atmospheres. But even with a melting point over 2,300 degrees Farenheit, this metal needs assistance to survive the 4,000-degree temperatures experienced in the combustion chamber. To help keep temperatures down, the fuel is passed through channels around the outside of the combustion chamber, a method known as regenerative and film cooling.

5. Fuel

Unlike its sister group that uses solid propellants, the Liquid Propulsion Lab gives students the opportunity to explore liquid propulsion technologies that are commonly used in the aerospace industry. As such, Balerion is fueled by liquid oxygen and Jet A, a kerosene-based jet fuel.

6. International collaboration

The Liquid Propulsion Lab has worked with students at the Kyushu Institute of Technology in Japan to design and build the rocket that will house its Balerion engines. While USC students build and test the propulsion system — including the engine, fuel feed systems and related electronics — their colleagues in Japan are building the flight vehicle, which consists of the shell, parachute system and the majority of the electronics. Students at both schools have spent semesters learning from and working with their collaborators across the Pacific.

7. What’s next?

In accordance with the lab’s mission to emulate the processes and standards of industry, each component is thoroughly tested after it is built. In the fall, the engine went through a cold flow test in which nitrogen and water were pumped through the fuel feed system. This helped them verify their design and gain experience with their testing stand before they perform the first test fire of the engine this spring.