135-lbm Bipropellant Recovery System

Outcome & Impact

Currently deep in the testing phase, I led the complete redesign of a dual-deploy parachute recovery system for a 135-lbm liquid bipropellant rocket. The goal is to safely recover the vehicle from a 100,000 ft apogee. Right now, we are running integrated 1-atm deployment tests, validating our vinyl black powder (BP) charges, and testing the flight computers in a custom vacuum chamber to simulate high-altitude conditions.

Experience & Skills

Role: Separation and Recovery (SepRec) Lead / Hardware Consultant

I took a look at the legacy architecture and redesigned everything that could be redesigned (excluding the bulkhead) to a minimum 2.0 Factor of Safety (FOS) per NASA standards.

• Component Selection: Individually selected literally all COTS hardware—down to the AIM Xtra GPS flight computer and batteries—balancing our strict 20-lbm weight limit against redundancy, lead time, and cost.
• Precision Machining: Drew up machining diagrams and personally manufactured aluminum test cable cutters on a manual lathe, cutting the mass by 49.5%.
• Analytical Calculations: Pulled from five different aerospace papers to calculate our parachute opening shock (823 lbf) and snatch loads (1,230 lbf) by hand, as open-source scripts proved inaccurate.

System Validation & Testing

We needed to physically validate our math before flight, so we pushed the hardware to its limits:

• "Gunpowder Cannon" Splice Testing: Used a custom gunpowder cannon setup to hit our untested line splices with a 2,000 lbf shock load. They survived easily, proving a >1.5 FOS.
• Vacuum Chamber Validation: Designed a 263.6 L medium vacuum chamber to validate sealed pyrotechnic charges and avionics at 0.011 atm. Designed the face seal using a 381 square O-ring based on the Parker O-Ring Handbook.
• Pump Architecture: Used a Robinair 15310 3CFM roughing pump for rapid pull-down, paired with an Alcatel 2008a to reach target absolute pressure.
• Pyrotechnic Data: Tested BP charges inside the vacuum chamber using a Pressure Transducer (PT) to track pressure spikes and validate shear pin failure loads.

Motivation & Constraints

Objective: Safely recover a 135-lbm dry mass vehicle from 100k feet.

Premature deployment at that altitude is a massive safety risk, and drifting into government-restricted zones carries severe legal repercussions. Building this infrastructure is step one toward the club's ultimate goal of a collegiate liquid bipropellant spaceshot.

• Mass Budget: < 20 lbm (Achieved 18.7 lbm)
• Financial Budget: $1,076
• Development Time: 4 months (pre-testing phase)