Our first rocket. A 600 kg, liquid-fueled suborbital vehicle on our Big Piggy kerosene and liquid oxygen engine, built to fly to at least 100 km, the edge of space, in late 2027. The $500,000 program budget covers research and development, about $150,000 of hardware, and room for failures along the way. It exists to test, on a real flight, the systems every later Stellar rocket depends on.
See the Specs
An orbital rocket is too expensive to learn on. The Guinea Pig gives us the same kinds of answers for a fraction of the cost: real engine, real flight, real data. The name is the point. It is the test subject for everything that follows.
When it reaches space, The Guinea Pig will be the first student-built liquid-fueled rocket to get there.
Every later vehicle is designed in our own trajectory and engine simulations. A real flight to 100 km tells us exactly where those models are right and where they are wrong, before we design an orbital rocket on top of them.
The Guinea Pig carries our flight computers, telemetry, guidance and engine steering (thrust vector control) through supersonic, high-heat flight. Spark’s landing software is then trained on this real data.
It flies a small-scale version of the Chameleon payload rack and its click-on adapter, along with the software that arranges payloads and shows where each one mounts. The same design scales up on Spark and Lightning.
Big Piggy is 3D printed in Inconel 718 for rapid, simple manufacturing and has been through more than 63 design iterations. Our goal is to bring the cost of an engine from over $100,000 down to around $15,000, the same approach that lets us print Firebird and Phoenix engines at fleet scale.
| Engine | The Big Piggy |
|---|---|
| Height | 8.35 m |
| Diameter | 30.48 cm |
| Propellant | RP-1 / LOX |
| Wet Mass | 600 kg |
| Dry Mass | 300 kg |
| Minimum Apogee | 100 km |
| Goal Apogee | ~150 km |
| Simulated Apogee | 112.9 km (103 to 124.2 km) |
| Burnout Velocity | 4,961 km/h (Mach 4.67) |
| Average Specific Impulse | 265 s |
| Vacuum Specific Impulse | 300 s |
| Chamber Pressure | 40.4 bar |
| Burn Time Target | 30 s |
| Sea-Level Thrust | 23.7 kN |
| Peak Acceleration | 8.2 g |
| Total Impulse Target | 781,930 N·s |
| Peak Mass Flow | 10 kg/s |
The Big Piggy uses a 3D-printed Inconel 718 shell (every Stellar engine is 3D printed in Inconel 718), selected for strength at high temperature and manufacturable chamber geometry.
The Big Piggy is pressure-fed and uses RP-1 / liquid oxygen. Firebird and Phoenix move to methane and liquid oxygen, electric pumps and regenerative cooling.
A sacrificial liner absorbs and carries away heat during the burn, so the engine needs no cooling channels. That keeps the first engine simple and cheap to build.
The Big Piggy is built to fly once and teach us as much as possible.
The Phase 1 program budget, line by line. This is the round we are raising now.
Estimates for the full 2027 Phase 1 program. The itemized lines come to about $380,000 to $440,000; the rest of the $500,000 target is held as reserve.
The Guinea Pig’s data flows straight into Spark, our orbital demonstrator with 9 + 3 Firebird engines and a 100 kg payload.
Explore Phase 2