Adding Feathers to a SpaceX Rocket
Each year many Mudd students participate in clinic, a program designed to fulfill Mudd’s mission statement of teaching engineers and scientists who are aware of their ability to change and improve the world around them. Clinic brings together companies who have a problem they would like solved and groups of Mudd students who have the skills to explore and solve the problems. Projects vary greatly in both purpose and scope, but all of them give students a chance to apply the concepts they’ve learned in the classroom to real-world projects and learn new things too.
One of the many companies that collaborated with Mudd last year was SpaceX, an aerospace manufacturer. Graham Gordon ’15, Gourav Khadge ’15, Robert Gambee ’15, Kristina Ming ’15, Kaitlin Kimberling ’16, and Erick Kiss ’15 worked in conjunction with their advisor Prof. Albert Dato and SpaceX liaisons, including Mudd alums Casey Schilling ’08 and William Ferenc ’13, in order to design a recoverable Ethernet flight data recorder.
According to the design statement, the data recorder needed to accomplish three tasks:
- “record and store data in high vibration environment”
- “survive the extreme conditions of rocket ascent, stage separation, and vehicle failure”
- “be easily recoverable in the event of catastrophic vehicle failure in the ocean or at high altitude”
Kimberling explained that “based on this project statement, the problem was split into multiple parts: recording and storing the data (electrical and software development), protecting the data recorder (mechanical housing), deploying the recorder during a crash landing, and recovering the deployed data recorder.” She worked with the team during the spring semester, and so got to see the shift in focus of the project. Originally, the team had planned to make the “black box,” which they named The Feather, detachable from the rest of the rocket so that if the rocket failed, the feather could deploy and the data would still be safe.
However, “during the spring semester, we realized that getting the box to reliably deploy from the rocket and then transmit its location for recovery would require a lot of sensors and expensive hardware, and we probably wouldn’t have enough time to develop the algorithms for reliable deployment,” Kimberling said. Moreover, on successful flights the black box would not need to deploy.
“This led us to pursue a smaller, inexpensive black box that does not deploy from the rocket,” Kimberling said. “Several of them can be placed on a rocket at once, increasing the chances that at least one of the black boxes is found on a piece of debris,” so that the data is still recoverable in the event of a failure.
In fact, this allowed their final feather to be smaller and cheaper than commercially available black boxes. These standard black boxes are 10 kg and cost $10,000, where the feather they designed weighed only 0.9 kg and would probably cost somewhere between $200-$800. After completing their black box, the team presented their results at Projects Day in May.
“The goals of our Projects Day presentation were to show that we designed and created the PCB and software interface for the data logger in addition to the mechanical housing ourselves. We designed the PCB and software to handle high-speed signals and for durability. We also designed the mechanical housing for durability and performed several simulations and physical tests to show that the data (stored on an SD card) would survive a nominal or catastrophic flight,” explained Kimberling.
While there are standards for “vibration and thermal loading experienced during a nominal flight, […] we had to come up with a way to test survivability during a catastrophic flight, which is not defined by any current standards,” said Kimberling. So in addition to testing for the normal standards of flight, the team also “hit the box with a sledgehammer to simulate impact, applied a blowtorch to simulate the heat or reentry, and exposed the SD card to saltwater to simulate an ocean landing.” The feather survived all of these simulated flight conditions, leading the team to believe that it could be a viable replacement for black boxes.
Clinic projects every year challenge students to find innovative solutions to real-world problems. Partnerships with companies such as SpaceX produce products that can be used in the real-world and help students form connections with professionals in many fields.