Propellant Feed System

1000N & 2500N Engine Validation

Engine and PFS design are my two biggest strengths. Over my last 5 years of experience with hybrids and now liquids, I am most comfortable in designing an engine and going through the entire process of creating a pressure ladder, figuring out what valves should be on there and where, mapping fail-safe states, writing procedures, and actually bringing the whole systme to life. I have worked with both swagelok and JIC systems with a maximum pressure of 250 bar.

With that being said, I am also well familiar with the physical side of it including leak checks, pipe bending, flaring, and running coldflows and hotfires. Since working with nitrous consistently with the engine at GTPL, I have also built up my experience working with saturated fluids like nitrous and thus, unfortunately, is familiar with the complications that come with them. This includes a range of things that can be as specific as the weird high dP transient effects you get during startup, or just learning to deal with the effects of nitrous flashing and how to design systems around, or accomodating, them. For more, check out the ARRC grid!

Injector Development

Showerhead Injector

Iterative injector design, manufacturing, and cold-flow validation. Since we're working with a nitrous system, we frequently work with all flow models including Single Phase Incompressible, Homogeneous Equilibrium Model (HEM), Non-Homogeneous Equilibrium Model (NHEM), Dyer and Omega Model, to predict our oxidizer mass flow rate. Post hotfires, we also run analysis like FTT to determine if there was any combustion instability.

Fun fact! For our first N2O full-throttle hotfire with the engine, we observed a ~430hz acoustic combustion instability that also propagted upstream of our PFS. We determined the cause was due to poor stiffness so the very next week we tested a new injector variant and the instability was no longer observable. If you visit our youtube channel and watch the actual hotfire, you could hear it very clearly. ↗

Throttle Valve

Throttling mechanism for Monarch, our 1000N lander

Hybrids may not have the difficulties of regen design or handling of very sensitive fluids like LOX (well, unless you've got a LOX hybrid), it is just as hard in its own ways especially when it comes to control. Think of it like this: For liquids, you have control authority over both of your fuel and oxidizer mass flow rates at any point in time. This enables you to do wonderful things with the main advantages being precise throttling and at your desired O/F. Hybrids on the other hand, do not have that advantage. For hybrid rocket engines, you (typically) have a solid fuel and liquid oxidizer. Thrust, in this scenario, is entirely dictated by the oxidizer mass flow rate. And unfortunately, the relationship between oxidizer mass flow rate and the thrust created by the engine is rather complex. So complex that no one in the world, as of 2026, has successfully achieved a free, controlled flight with a hybrid lander. The farthest anyone has ever gotten in history was a successful tethered hover completed by ARRC in 2022.

Hence, the crazy and ambitious things we're about to do with this throttle valve! It is an in-house developed throttle valve that uses a v-port ball valve and mounted to two high-torque servos. The team has developed a PI/PID controller which we will throttle our engine with using chamber pressure as feedback. Characterization tests are underway and will be completed by October. The throttle valve, accounting for erosion and regression rate changes over flight, will enable us to adjust our thrust precisely to achieve the tethered hover and subsequent hops.

1000N N2O/Paraffin Engine

Some call him Godzilla, others call him 1500N

Lander main engine that I designed from scratch. The engine uses N2O as our oxidizer and paraffin as fuel. For ease of manufacturing, paraffin is casted in an ABS gyroid structure at 10% infill for increase in structural integrity while maintaing regression rate. The main combustion chamber is ~23cm long and then engine is designed to sustain 40 seconds with an average O/F ratio of 7.1 to burn slightly fuel rich. The engine is designed with an operating chamber pressure of 40 barA and has a ~3cm long pre-combustion chamber for the purposes of increasing combustion efficiency to address partial combustion typically seen with liquefying fuels such as paraffin.

T-3 Hours before Presentation

Shout out to my co-presenter, Suhaila Rashid!

For this conference, our paper was on the system architecture of our 1000N lander. In this paper, we wrote about the high level decisions we made for the lander and the rationale behind it. Inside the manuscript documents all the system and subsystem requirements that were derived from the mission objectives. As the limit for AIAA student conference papers caps out at 11 pages, we were unable to go into depth. However, highly recommend it for a read if you are interested in understanding our work in detail. GTPL is doing extraordinary things in a very short time frame!

CFD & FEA

I run simulations where useful!

CFD is for dP purposes and initial design estimates. Though, nitrous is a bit tricky because trying to model a saturated fluid is kind of a nightmare that I have yet to overcome with confidence. For structural analysis, recently I have started to use it for transient thermal analysis more frequently. I run all of them on Ansys! For multiphase flows, I'd like to explore OpenFoam if I have the time.

ARRC's KeroLOX LRE & Others

PFS Design & procs including safety and chilldown + many others.

On this project, I was heavily involved in the PFS design and what had to change when dealing with the handling of LOX. This included chilldown procedures and whether we wanted pulse, or continous, and for how long. Other things included the design of PFS so valve placements, making sure there are no trapped volumes, and that all valves have well thought out failed states in all possible fail scenarios. Lots of lit review + a couple case studies on other typical failure modes in LOX systems. Recently, I have been working on implementing liquid & gaseous film cooling correlations which will be used for future designs and integrated into ARRC's own optimizer. On my own, I also have a fully self-developed script that combines regen and film cooling and implements genetic algorithm to determinal optimal channel dimensions while accounting for ease of manufacturing.

In my many years at ARRC, I have also worked on other projects that are hybrid related. Coming into my internship for the first time in 2022, I was tasked, along with a couple other interns, to determine the regression rate of different fuels like PMMA, HDPE, PP, and Paraffin to study the changes in regression rate in ambient conditions. Following that, I was involved in a research project on a type of high speed regression fuel and blends with that fuel where the lab, in conjunction with another lab in the Department of Materials Science and Engineering, NYCU, ran tests including Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA).

Akashbani Close-Up

Only very few minutes before the NOTAM window closed.

Akashbani, or translated to english as "A message from the sky," was AERD's first weather ballon that we had launched in 2024. The goal was to develop a simulating platform for CubeSats that we would use not only to collect data for AERD's future rockets, but a project which we would then distribute around universities in Bangladesh as a means to support and grow the scientific community.

← At NESS

Organized by the Notre Dame Eco and Space Club (NDESC)

AERD, in its prime, was the leading organization of rocketry development in Bangladesh. Not only had we tested the country's first hybrid rocket engine but we continued to do so consistently for over a year and half with very limited resources. As such, one of our core pillars, aside from developing these technologies that weren't previously seen in Bangladesh, was to educate and promote the importance of these space technology. On that end, we frequently gave seminars and worked with different programs to coordinate such efforts. Aside from NESS, we've also gave these seminars at an IEEE Aerospace and Electronic Systems Society event @ BRAC University, another at the American International University Bangladesh (AIUB), and one at a olympiad hosted by the Bangladesh Space Research Society (BSRS).

SR-400 Qualification

Participated in the tests TASA ran over summer.

During my internship, most of my tasks were designs for the future vehicle so I was unable to see them through to manufacturing. There were other ongoing projects however, like the SR700, so we would be at the test site to observe. Beyond the test-site things, I also went to the factory where they assembled the engine for a couple of days. I had three amazing mentors, Koko, York, and Sean, who all I will be seeing again this summer!

MONARCH, Hybrid Lander

GTPL's 1000N flagship lander. To be revealed.

Tethered hover coming this fall.

100N Lab-Scale HRE

Highly modular test bed for all GTPL research.

Low thrust, high chamber pressure, high duration. It will be able to accomodate a wide range of research projects before the team implements them into future lander engines.

Regen & Film Cooled Nozzle

For future GTPL landers and on the road to zero erosion.

One of the many projects which will be validated on the lab-scale. The team will develop a full in-house regen + cooling script that will continue to be refined over time with experience and literature.