As part of the 2022-23 NASA SLI Challenge, I led a team to build an Active Aerobrake System. The goal of this system was to bring the rocket to a previously set apogee. The system had a few parts: First, it continuously predicted the apogee, using current height, velocity, and acceleration data to do so. Then, if the rocket was overshooting the apogee, it would deploy three fins to increase the rocket’s drag. This was tested and refined, and we successfully deployed the airbrake system at the NASA SLI Launch in Huntsville.
Designing and Testing the Fins
We designed the fins and fin deployment method in Fusion 360. The contraption for the fins includes holes for wires and holes for the rods to go through so we could mount it on the rocket. Images of the CAD model are below:
Contraption for the Fins
Fins and Center Piece
After designing the system on Fusion 360, we went through multiple iterations of printing and refining the system to make it work flawlessly. Videos of the fins deploying and retracting both outside and inside the body tube during testing are below:
Actively Predicting the Rocket’s Apogee
The Arduino, functioning as the central controller, processed data from the IMU (Inertial Measurement Unit), which provided information on the rocket's orientation and motion. We used a Kalman Filter to clean noisy data and enhance the accuracy of the prediction. By using fundemental physics equations, the system could predict apogee in real time, allowing the fins to make fine adjustments and ensure optimal performance throughout the flight.
Results
The project yielded great results, significantly improving the accuracy of apogee prediction compared to earlier attempts. While it didn’t perform exactly as hoped, the system brought the rocket much closer to the desired apogee using real-time IMU data, a Kalman filter, and simple physics. This effort earned the team the NASA Payload Design Award, recognizing the innovative design and engineering solutions they implemented.