Overview
I built HORIZON, a self-stabilizing, thrust-vector-controlled model rocket, from scratch. HORIZON I flew imperfectly in October 2023 on a 3D-printed TVC gimbal and RP2040 avionics I wrote myself; I mixed and cast my own rocket fuel for the ground tests before switching to stock engines. HORIZON II followed with the refined all-aluminum TVC mount and STARLIGHT avionics, built on everything I learned from the first launch.
Technical materials
What I learned
- 75mm BlueTube airframe with a PETG-printed TVC gimbal (K-9 Gen 2, later my own fifth-iteration design) for HORIZON I
- Real-time PID control and sensor fusion (via the micropython-fusion library) on an RP2040 (MicroPython) using an ICM-42605 IMU, achieving roughly +-2-3 degree steady-state attitude accuracy
- HORIZON II rebuilt around STARLIGHT avionics and a refined all-aluminum TVC mount (see the two dedicated TVC write-ups for the gimbal iteration itself)
- Custom rocket fuel formulation and casting - a 65:35 potassium nitrate/sorbitol mix, ground-tested before flight - later replaced with stock engines after a two-month detour
- Designed and iterated the TVC gimbal itself five times before converging on a manufacturable, space-saving design (servos mounted above the pivot, linkage-actuated)
Project related blog posts
- The Story of my Model Rocket, HORIZON I
- The Hidden Layer of HORIZON I: Software Struggles
- TVC Hardware: The Sister to STARLIGHT
- The Launch of HORIZON I
- HORIZON II - The Next Step
- STARLIGHT V2 and Thrust Vector Shenanigans - HORIZON II Design Process
- Explosive Chemistry: Cooking My Own Rocket Fuel