Structures and Recovery Lead at PSP-Liquids 2022
Starting in the fall of 2021 I joined Purdue’s liquid rocketry team: PSP-Liquids to work on launching one of the first student-built cryogenic liquid methane - liquid oxygen rockets: Boomie Zoomie B. In my first semester I served as the recovery system responsible engineer, provided electrical and mechanical build support for hotfire operations, and lead a team designing a filament winder. In the spring semester I stepped into the Structures Lead position, taking full responsibility for the safe construction and recovery of the vehicle for the two April 2022 launches, as well as the surprise Boomie Zombie launch in June 2022. For the June 2022 launch, I also designed a custom pyrotechnic valve actuator to mitigate an engine starving failure mode identified in the earlier launches.
Fluid System Support
The first weeks of the semester were spent preparing the vehicle tanks and ground support equipment in build up for propellant flow and engine fire operations. One of my contributions was mounts for the vehicles run-valve actuators ground side rotary pneumatic actuators that turned the vehicles onboard propellant feed valves. Little did I know that these valves would be a thorn in my side for the next 8 months.
Both of the April 2022 launches, while beautiful, were plagued by low mass flow rates into the combustion chamber as the ground side run valve actuators were unable to fully open the the run valves before the vehicle had moved up the rail. The team knew that a new valve actuator was critical if the vehicle was to fly again
The team ran multiple ground tests of Burnie Turnie to verify its operation before use on the launch vehicle.
In the first vehicle cold flow it was found to be next to impossible align the valve actuators with the valves themselves, invalidating vehicle thrust measurements, which required a quick fix before the next operation. Within 3 days of identifying the problem, the new actuator mounts were installed, which mounted directly onto the run valves rather than to the ground.
My answer to the valve actuation problem was Burnie Turnie: A self contained valve actuator that used a small quantity of black powder to pressurize a cylinder which turned the run valves via a crank. The pyrotechnic nature of the system meant that it was incredibly easy to control, redundant, fast acting and light. This project was incredibly exciting as it leveraged my past experience in a number of areas including manufacturing, motion systems, and black powder handling.
Burnie Turnie was purposefully oversized to overcome the stiction associated with operating in a frost filled enviroment.
Recovery
Starting my role as Recovery RE, I inherited the “Bag in Air” design which released a bag into the airstream at apogee containing the main parachute, which would be released later in flight. This necessitated thoughtful management of the control wires, which ran along the 40’ shock cord from the vehicle to the main parachute release system. I chose to pack the line using the “Over-Under” method used extensively by TV production grips to create bundles of wires that release with no twists.
Careful stewardship of all softgoods was nessecary to ensure that flight hardware did not incur damage during devlopment testing.
The April 2022 launches were remarkable learning experiences for the recovery team. The system failed in very different ways each time, resulting in multiple changes to the system that ensure the main parachute was well retained and did not over stress the vehicle during deployment.
Pictured is the recovery system as flown on Boomie Zoomie in June 2022, featuring a new deployment bag, secondary retention systems for the main parachute bag, and a “shock pack” for reducing the main deployment shock load. This system performed nominally during the flight thanks to these upgrades.