Mini-Red

Launching a full-scale dual-stage rocket to 33,000 ft and Mach 2.0 can be a little intimidating — especially when it’s your first dual-stage rocket and the first one you’re fully in charge of. That’s why I built Mini-Red, a sub-scale dual-stage rocket with a target altitude of ~3,000 ft.

Mini-Red is ITR's first sub-scale dual-stage rocket, acting as the test bed for a full scale one rocket, BIG RED. The goal of Mini-Red was simple: test wiring, programming, and avionics for stage separation and sustainer ignition before risking it all on Big Red 1. With budget constraints in mind, Mini-Red was built primarily by reusing Level 1 rocket kits and parts available in the lab — including two Patriot rockets and fiberglass tubing from older projects — and modifying them to fit a dual-stage configuration.

Modification

Stability Fix: The kit’s fins were too small, making the rocket unstable. To fix this, I added a fiberglass nose cone to the sustainer for extra mass, increasing the stability
Materials: I reused spare fiberglass and carbon fiber tubes from the lab for the sustainer and booster airframes and interstage coupler
Fin Modification: The original fin design didn’t account for a coupler. I had to cut into the fin roots to make space while still keeping them structurally strong.

Motor Selection

Based on lessons from Big Red 1, I selected:
- Booster: H550ST for high off-rail velocity.
- Sustainer: I161W, not the most powerful option, but good enough for testing, and importantly, it was available in the lab (budget constraints).

Stage Separation & Sustainer Ignition

Booster Separation: 2 seconds after motor burnout
Sustainer ignition: 1s after stage separation
Tilt lockout: 15 degree
Altitude lockout: 700ft
Velocity lockout: 200ft/s

Avionics

Just like Big Red 1, Mini-Red carried redundant avionics bay in both sustainer and booster:

TeleMega V5 (main) – GPS tracking, live telemetry, accelerometer, barometer, gyroscope.
Blue Raven (backup) – Bluetooth connection for ground testing and tilt-angle lockout.

Both systems had separate wiring, switches, and batteries for full redundnacy. If TeleMega failed at any stage — separation, ignition, or parachute deployment — Blue Raven would immediately take over.

Power system:

TeleMega: Two 1s LiPo batteries (separate pyro + power). The Telemega pyro and power is powered separately to extend the working battery life.
Blue Raven: One 2s LiPo (lower draw since it doesn’t transmit GPS). Since Blue Raven doesnt have GPS system or RF transceiver, it drew much less power and can last for longer with one battery.

Ground station:

TeleBT + TeleDongle with Altus Metrum software.
5-element 433 MHz Yagi antenna for live tracking.

Test Flight

Mini-Red launched on October 21, 2023 from Princeton, IL. The rocket left the rail at 72 ft/s, and one second after booster burnout, the booster fired ejection charge to separate the booster from the sustainer.

One second later, the sustainer was supposed to ignite — but because of strong winds, the rocket tilted ~15° off the pad. This triggered the tilt lockout, so the sustainer motor never lit. Despite that, all recovery systems worked perfectly. Both stages were safely recovered without damage.

Lesson Learn

Even though the sustainer didn’t ignite, the flight proved that the avionics wiring, stage separation, and recovery systems all worked exactly as designed. More importantly, the test highlighted how sensitive tilt lockouts can be in windy conditions.

For future flights, I decided to increase the tilt lockout threshold slightly to account for high-wind days — while still balancing safety.