Columbia Space Initiative:

Introduction

After leading the fluids team in 2022/23, I became the Co-Lead of the entire Columbia Space Initiative (CSI) Rocketry Team in 2023/24. The Rocketry Team designs, builds, tests, and launches high-powered, nitrous / paraffin wax hybrid rockets. I led the 50-person team to launch the school’s first two hybrid rockets at Spaceport America 2023 and FAR-OUT 2024. At FAR-OUT, we achieved 2nd place in the 30,000 ft group with a successful recovery, produced over 1200 lbs of thrust, and sustained 16G’s of acceleration. 

My responsibilities as team lead were to set the overall design architecture of the rocket and coordinate with our airframe, avionics, combustion chamber, fluids, structures, testing, recovery, and launch teams. This included deciding our target flight apogee, setting mass and length budgets to maintain stability, providing input on critical design decisions, running static fire tests, diagnosing testing issues, and directing the launch. 

On the logistical side, I also documented and wrote procedures for static fires, hydrostatic tests, and launches. I was in charge of securing funding through sponsorships and grants, approving purchases, and keeping track of budgets. For our competition, I organized travel for the entire team, found lodging and accommodation, and arranged the freight shipment of our rocket. 

High-Level Design of the Rocket

I collaborated with the combustion chamber, fluids, and airframe teams to work to set an altitude target by working from first principles. Together we first decided on a reasonable peak thrust of 1200 lbf that we could design upon. From there we made some bounding assumptions on the overall weight, length, and drag coefficients of the rocket. Using an in-house developed numerical solver, we iterated through variables like oxidizer mass, fuel mass, wet mass, and drag coefficients and optimized them for an apogee of 25,000 ft. 

We then developed a custom thrust profile using the Hybrid Rocket Analysis Program and input this into the OpenRocket Simulator. The OpenRocket simulation validated our expected apogee from our first principles analysis and informed our final mass and length budgets for each subsystem. We also used OpenRocket to iterate through fin designs to ensure stability by accounting for the changing center of gravity due to oxidizer usage. 

Shown below are the overall architecture diagram with some key metrics, our OpenRocket simulation setup and results, and our fluids piping and instrumentation diagram. 

Static Fires and Iteration

After spending the fall of 2023 designing and manufacturing the rocket, it was time to start static firing to learn about our designs. At this point in the rocketry team's history, we had never had a fully-successful static fire with good data readings. Our goal was to reach 1200 lbf with reliable ignition, designed burn time, clean data, and of course an intact rocket. 

Static Fire Setup

We static fired at the Columbia Nevis Lab, which is located upstate on the Hudson (we can't static fire in NYC for some reason). Our testing team designed, analyzed, and installed a steel test stand anchored in concrete with a factor of safety of over 4, a flame deflector, and a deluge system. All of the teams developed their own ground support equipment which included a tank heater to combat the chilly winter weather. I was in charge of running the test campaign and our first static fire was in February. 

First Fires!

Our rocket roared to life for the first time in March and then again a few weeks later. Both of these fires experienced major failures, which revealed some fundamental design flaws. We were ecstatic to see our rocket firing  and excited to correct our mistakes.

Challenges and Design Iterations

During our static fires, we ran into numerous challenges, the first major one was our first exposed graphite nozzle being blown straight off. Due to graphite being anisotropic, our finite element analyses were not accurate enough to predict this failure mode. We fixed this issue by redesigning and fully enclosing the nozzle in an aluminum retainer.

The next static fire revealed another major issue as we experienced a burn-through of our combustion chamber. Our chamber was made up of an aluminum shell full of multiple paraffin wax cylinders encased by phenolic thermal insulation layers and separated by multiple graphite baffles. These baffles were introduced to promote more mixing of the propellants and thus more complete combustion and higher efficiency. However, we failed to account for graphite being such a great thermal conductor and did not have any phenolic insulation on the outside of these baffles. As such, towards the end of the burn, the aluminum that was in contact with the graphite baffles was melted away and our rocket started releasing hot gas from one too many places. To remedy this, we enclosed the baffles in phenolic and saw great success. 

First Fully Successful Static Fire

After these iterations, we successfully fired our rocket at our designed thrust with good data for the first time in our team's history. As shown in the "Load Cell Sum" figure, we sustained 1200lbf for over a second (the time scaling is off). As seen in "OX Transducers", our oxidizer tank started at 750 psi was fully depleted at our predicted rate mass flow rate in about 6 seconds. The initial dip and subsequent recovery and decay in oxidizer pressure are characteristic of a nitrous blowdown system and were very close to our predicted values from our Python model. The blue thermocouple in "CC Transducers" experienced some sort of anomaly at the beginning of the burn but then recovered. The blue thermocouple measured pressure in the injector manifold while the orange thermocouple measured pressure downstream in the chamber. Overall, I was so proud to see  our years of hard work pay off and finally felt confident in actually launching.

Launch and Recovery at FAR-OUT 2024

Before shipping the rocket across the country to the FAR-OUT competition in Mojave, CA, we had to complete the final integration steps in May 2024. A small team and I worked around the clock to finalize shipping logistics, cut the airframe to size, create mating connections, line up rail buttons, and package everything onto a 500 lb pallet. 

Over in the Mojave Desert a week later, we assembled the rocket and ran through final tests. We ran into many problems such as microcontroller circuit boards being fried, our pyrocutter disconnect mechanism not working, and telemetry issues. We had a three-day launch window and due to these challenges and high winds, we were only able to attempt launch on the last day. 

With high winds looming in the afternoon, we had a short flight window. Finally, all the preparations were completed and we retreated to the bunker. As we began our fill sequence, we noticed an abnormality with the load cell weighing our rocket, which told us our fill level. We quickly detanked, diagnosed the issue, and then came up with a solution to prevent our rocket from binding to the launch rail. We retreated again. This time, as I was directing the fill sequence, we saw good readings. Once we were at the prescribed tank pressure and oxidizer mass, I ran through a go/no go check with the team leads, who all agreed that now was the time. 

I counted down to our pyrocutter disconnect actuation and then heard a loud pop followed by a hiss. In cutting the fill line with such force, we accidentally partially opened our closed servo-actuated ball valve. We were leaking nitrous! In a split-second decision, the team and I all decided to go ahead with the launch and initiated our firing sequence. The igniter lit the solid paraffin wax on fire and then 8 seconds later, our custom pneumatic valve delivered high-pressure nitrous oxide.

We watched in awe as our rocket sped up into the sky with a deafening boom followed by a loud screech. Despite the leak, our rocket still reached 16'Gs of acceleration during its shorter-than-expected burn time. We were all leaping for joy and had to calm down to look out for our parachute deployments. A few minutes later, we spotted it! Our recovery system worked and the rocket landed intact safely back on the ground. 

This successful launch and recovery was a first for the team and the pinnacle of my undergraduate experience at Columbia. After working on the team for 4 years and getting to lead them in my final year, I could not be more proud of what we accomplished. 

Below are some highlights from the launch, including different launch perspectives and post-launch interview that I did. 

Integration and Assembly

Final integration was completed at Columbia University in New York City. After shipping, final assembly of the rocket was completed at the Friends of Amateur Rocketry site in Mojave, CA. 

LAUNCH!!!

Pictured on the left is our rocket on the launchpad with accompanying ground support infrastructure including fill system, electronics, and quick disconnect wires. On the right is a still frame from the video of the launch.

Below these, the video shows the launch from multiple perspectives, including from the pad, from the bunker, and from a drone. 

Successful Recovery

Our rocket successfully deployed its drogue and main chutes. Although the main chute was a bit tangled, it still landed safely nearby in one piece. We brought it back for post-flight inspection and the vibes were great. 

Post-Flight Interview

The FAR-OUT Competition Live Stream conducted a post-flight interview with me. 

Technical Report