AKS
Three students at CHIREC International School, Hyderabad, set out to fly the highest student-led rocket in the world. Not from a launch pad, but from 30 km up, hanging beneath a hydrogen balloon.
A 2022–2023 proposal that never left paper. This is the flight it was designed to make.
TO SPACE
BY BALLOON
Strap the rocket beneath a high-altitude hydrogen balloon and let buoyancy carry it the first 30 km, above the densest air, then ignite. The proposal estimated the balloon would cut the cost of the project by nearly 25–30%.
- LIFT GAS
- Hydrogen
- HYDROGEN
- 258.42 kg
- LIFTED MASS
- 301.27 kg
- IGNITION
- 29 km / barometric
- TARGET
- 100 km / Kármán line
‘The sky is no limit when there is a vast and endless void above the atmosphere.’
—PROJECT AKS PROPOSAL, 2022
THE ROCKET
A 301 stainless-steel airframe coated in polyurethane against heating near the ozone layer and across the Kármán line. At the top, a 5–6 kg chamber for equipment the school wanted to send to space, with cameras at three different angles. Every component was meant to be tracked, collected, refilled and reused.
- STRUCTURAL MASS
- 150 kg
- PROPELLANT
- 151.27 kg
- LIFT-OFF MASS
- 301.27 kg
- AIRFRAME
- SS 301 / polyurethane
- TANKS & PLUMBING
- SS 321 / titanium valves
HYPERGOLIC
Unsymmetrical dimethylhydrazine and dinitrogen tetroxide ignite the moment they meet: no spark, no igniter, no ignition system to fail. Both are liquid at room temperature and need no near-absolute-zero cryogenic tanks.
- SPECIFIC IMPULSE
- 316.7 s
- MIXTURE RATIO
- 3 : 2
- FUEL DENSITY
- 0.793 g/cc / UDMH
- OXIDIZER DENSITY
- 1.450 g/cc / N₂O₄
- FREEZING POINTS
- −57 °C / −11 °C
- COMBUSTION TIME
- 0.31 s
RS-25
The Space Shuttle Main Engine was the project’s principal architectural inspiration, “with special focus on the nozzle”. The proposal closed with renders of it. Below, the choices the team made for their own engine.
- INJECTOR
- Showerhead
- CHAMBER
- Graphite / not SS 301
- NOZZLE
- Aerospike / 35:5
- BELL ALTERNATIVE
- ε = 36.4
- COOLING
- 5 candidates
TURBOPUMP
The bill of materials calls for two high-pressure turbopumps, gas-turbine shafts, high-psi turbines and fuel- and oxidizer-rich preburners. Keep scrolling to pull the rotating assembly out of its housing.
- HELIUM VESSEL
- 5000 psi
- PROPELLANT TANKS
- 3000 psi / ×3
- TURBOPUMPS
- 2 / high-pressure
- PREBURNERS
- Fuel-rich / oxidizer-rich
3D model: “Raptor CH4 Turbopump” by 3D Shuttle, Printables, CC BY-SA 4.0. Sectioned and re-materialled for the web.
PROFILE
Scroll to fly the mission as the proposal planned it: a hydrogen balloon to the stratosphere, a hypergolic burn, and a climb toward 100 km. Telemetry pressure is the International Standard Atmosphere at each altitude.
THE KÁRMÁN
LINE
Measured from the ground, a 30 km balloon start leaves 70 km for the rocket; measured from release, the goal was 100 km more. Either way: higher than any student-led rocket before it. Then home again: the team planned to predict the landing with thrust-to-weight formulae and GPS, and recover the rocket and parachute for reuse.
- APOGEE
- 70–100 km / by convention
- TRACKING
- 4 GPS
- RECOVERY
- Parachute / landing mechanism
- BUDGET
- < USD 25,000 / ≈ INR 2,00,000
DOSSIER
Feed system, materials, injector, nozzles, cooling, every calculation, the balloon trade study, permits, the full bill of materials and the independent review, transcribed from the original proposal without omission.