Control Freak: A rocket with attitude.

Members of the Liquid Rocketry at Illinois team drove to Pence, Indiana in mid-April to launch Control Freak – the student organization’s first rocket, facing the launch pad for the first time. Although the launch was successful, the rocket itself was lost.  After searching for it for more than two days, they decided to rebuild it from scratch and launched a Control Freak clone just eight weeks later at the International Rocket Engineering Competition in Midland, Texas.

“We finished 49 out of 141 teams at IREC, so almost the top third,” said aerospace engineering senior Brian Wu. He led the airframe technical group for The Grainger College of Engineering at the University of Illinois Urbana-Champaign rocket team. “There were a lot of teams that didn’t launch at all. With this being our first time in a competition and only our second time actually launching a rocket, I was absolutely happy with that result.”

How did the first Control Freak disappear?

“We lost GPS connectivity and had an anomaly with our parachute deployment system,” Wu said about the Indiana launch. “Instead of the smaller drogue parachute deploying first, our main, large parachute came out at apogee, so it drifted a long way. We searched the 100 square-mile area but couldn’t find it.” 

He said, with finals coming up, they debated about how best to move forward. They decided to reorder parts, secure additional funding, put in the hours to rebuild Control Freak and launch again at IREC.  He said it was a challenge, but he’s glad they were able to succeed and compete at IREC as planned.

Wu said LRI’s project charter is to be the first ever collegiate team to build a supersonic pump-fed, bipropellant liquid rocket. In addition to the airframe group, the club has technical sub teams working on the engine, the pump and internal structures and fluid lines. Because a lot has to happen before they can fully realize their goal of a liquid rocket, Wu said Control Freak was intended to tackle the first step, which is attitude control – to control the roll, pitch, and yaw of the rocket.

“It’s not as important for a rocket with solid propellant but when we get to the pump integration, it becomes more relevant. Excess roll can lead to pump cavitation, propellant slosh, and thrust loss.”

He said this past year as well as this coming year, the primary focus of his group is conquering roll control, which is where the rocket’s name came from. For Control Freak, the team chose to use active control surfaces for roll control.

“We used canards, which are like another set of super tiny fins mounted further forward on the rocket,” he said. “The two canards move in opposite directions. When you actuate them during a flight, they induce a roll moment of the vehicle.”

Control Freak had several flight computers on board, one of which was HAL-1, whose job was to drive two servo motors that actuate the canards and damp unwanted body-axis roll.  

“We ran simulations to measure the roll-control capability of the canards and evaluate the roll-reversal phenomenon, where the vortices created at the tip of the canard generate a rolling moment opposite to the moment produced by the canards themselves.”

As a part of their technical report, Wu created a top 10 list of lessons learned.

“One of the distinct challenges student teams face is the student turn-over from year to year,” he said. “I had fun writing this portion of the report and hope it will be a helpful resource for future Liquid Rocketry at Illinois leads and members.”

1. Every requirement not captured up front becomes more expensive to address as the design matures.
2. Design for manufacturing, assembly, and subsystem integration from the outset.
3. Substitute magnetic switches to eliminate holes.
4. Integration ergonomics are a prerequisite, not a luxury.
5. Anomalies must be investigated, even when they appear harmless in isolation.
6. Bench-testing does not equal flight conditions.
7. Avionics requirements should be derived from desired operator capabilities during launch, not just from desired flight functions.
8. Task sheets are the single most valuable team-management tool to track deadlines, record active work and assign explicit ownership.
9. Cross-team communication and high subsystem ownership are vital.
10. Clear ownership and documentation preserve accountability and institutional knowledge.

Team adviser, Joseph Gonzalez,  teaches a class which is mandatory for student team leads and sub leads, mentioned the team’s resilience and determination after the failed rocket recovery in April.

“Independent reviewers called it a bold move because of the tight timeline to retest the systems, machine and order parts, etcetera,” Gonzalez said. “I was impressed with the team on their passion and dedication to get a brand-new rocket done in less than 1.5 months.

“They had a great first outing at the competition and I was very pleased with how they handled my expectations to not only rebuild the rocket, but to retest so we could be confident in the launch. They demonstrated rocket roll control for about one second of flight which was a great accomplishment as a first time for our university.  And the fact that they recovered the rocket successfully is a testament to their corrective actions and dedication to address concerns.”

This summer, Wu has been at NASA’s Kennedy Space Center in Florida doing thermal analysis work for the commercial launch service program. He will be an aerospace senior this fall.

Wu expressed how grateful the team is to Gonzalez for his help and oversight.

“He enforced thorough systems engineering practices and gave us real-world experience with industry standards, something not a lot of college students get.”

The team is supported by Ansys, Relativity Space, Collins Aerospace, Shield AI, Stoke Space, Epsilon 3, Blue Origin, Kenesto, Parker and Seamless Tanks. Additional funding comes through donations, grants and the university.