PROJECT 01 / PAYLOAD DESIGN
IPEx Suborbital Flight Experiment
Designed, assembled, and tested two experimental payloads for Blue Origin’s NS-29 mission on the New Shepard rocket.
Purpose
The bucket drum is what IPEx (Infrastructure Pilot Excavator) uses for collecting regolith (moon dirt). Earlier experiments scaled the RASSOR 2 bucket drum design to smaller and larger IPEx sizes to study digging performance, regolith collection, and actuator torque loads. These results helped guide actuator sizing.
A discrete element modeling (DEM) study then compared how different spiral geometries moved regolith through the drum, using total mass collected as the main performance measure. Straight and diverging spiral designs were selected for further testing in the flight experiment.
My Contributions
- Led the mechanical design, assembly, and testing of two bucket drum payloads for experiments under simulated lunar gravity. Created and maintained the complete mechanical CAD in Creo, including part models, assemblies, and design revisions.
- Performed pressure and quasi-static structural analyses in Creo Simulate, refining the design to reduce stress concentrations and meet Blue Origin’s New Shepard payload safety requirements.
- Presented the design at a Critical Design Review with KSC chief engineers and a Payload Data Package Review with Blue Origin to proceed to procurement.
- Led vacuum decay and helium leak testing, random vibration and half-sine burst testing at the KSC Vibration Lab, EMI testing at the KSC Electromagnetics Lab, and mass properties measurements per the New Shepard Payload User Guide.
Key design decisions
Managing mass around an uncertain locker weight
The payload and its Blue Origin locker had to reach a total flight mass of 38 lb. Locker-weight variation left a payload mass budget of approximately 26 ± 1 lb, with the actual locker weight confirmed at the launch site. I tracked every component down to screws and washers and used structural FEA to guide weight reductions while maintaining strength for launch loads.
The design retained 1 lb of worst-case mass margin. I brought ballast to the launch site and added it after weighing the assembled hardware to reach the required flight mass.
Controlling outgassing before flight
Pressure inside the experiment had to remain at or below 10−1 Torr during flight. A roughly 16-hour wait inside the rocket, with temperatures up to 100°F, made outgassing from the regolith and other components a concern: released gas could raise the pressure before the experiment began.
I ran repeated pump-down tests and heated the payload while it was connected to a turbomolecular pump to remove released gases. I then kept the payload under vacuum for weeks at approximately 10−6 Torr. During flight, pressure reached 10−3 Torr—100 times lower than the maximum allowable pressure.
Balancing structural strength and flight mass
I owned the mechanical CAD in Creo and used pressure and quasi-static structural analyses in Creo Simulate to identify stress concentrations and refine the design. These analyses guided component optimization while keeping the payload within its mass budget and meeting New Shepard’s structural safety requirements.
I carried the design into manufacturing through internally reviewed and formally released drawings and BOMs, and coordinated the mechanical interfaces with the launch vehicle. I also led vibration and EMI testing, mass-properties verification, and the mechanical portion of the Critical Design Review, presenting the results to demonstrate readiness for flight.
Flight outcome
The payloads operated as expected during the suborbital flight, and experimental data was successfully collected.
Read the design overview — page 22
Van Horn, TX, 2025
Next project: IPEx TRL 5 Robot