KRPL
Onboard Rocket Control Avionics(ORCA)
ORCA is KRPL’s custom PCB avionics stack designed and built in house. It combines barometric and inertial sensing with high rate onboard logging, LoRa telemetry, and dual pyro deployment capability in a compact, field serviceable board.
ORCA I has flown on an Ares vehicle; all upcoming Ares vehicles will standardize on ORCA for reliable deployment and actionable flight data. Each revision tightens integration, improves noise margins, and reduces mass to support transonic and high altitude missions.
ORCA I
ORCA I was the first prototype of the Onboard Rocket Control Avionics system, flown on Ares I. It was built on a perfboard and powered by a 3.7V LiPo battery, which supplied unregulated voltage directly to the Heltec LoRa V3 board.
The Heltec’s onboard regulator stepped the voltage down to 3.3V, which was then used to power all peripheral components. A custom 3.3V power rail was manually distributed from the Heltec's 3.3V output, feeding the barometric sensor, IMU, and microSD module.
ORCA I featured onboard data logging, sensor fusion, and live Wi-Fi telemetry streamed through a custom web interface.
ORCA II
ORCA II is KRPL’s first custom PCB flight computer, designed and built in house. It runs on an Arduino Nano with an 11.1 V LiPo power system and onboard regulation, pairing a barometric altimeter with a 6 axis IMU.
High rate microSD logging and dual pyro channels bring dependable recording and deployment capability in a compact, robust board.
It introduced KRPL’s formal state machine with ground idle, arming, launch detect, ascent, apogee, chute descent, and touchdown.
A full end to end ground state test in a Tesla passed with flying colours, verifying code logic, sensor timing, power integrity, data capture, and safe pyro channel behavior. ORCA II served as a purposeful testbed, delivering the architecture and data that now underpin a smaller, flight ready ORCA III.
New gen: ORCA III
ORCA III is KRPL’s most advanced PCB flight computer to date, now in manufacturing. It returns to the ORCA I philosophy with a Heltec WiFi LoRa 32 V3 at the core, adding native LoRa telemetry and a stronger antenna for longer range and cleaner links. Designed in house by Reich Kiambati, the board is compact, rigid, and field serviceable.
Sensing and logging are handled by a barometric altimeter and a 6 axis IMU on a fast SPI bus, backed by high capacity SPI flash for lossless data capture. Power architecture centers on a 3.7 V LiPo with clean regulation and a separate armed pyro rail. Dual low side pyro channels provide dependable main and drogue firing, with screw terminals for battery and e-matches, USB C access through the Heltec, and corner mounting points for easy integration.
The software stack refines the ORCA II state machine with ground idle, arming, launch detect, ascent, apogee, chute descent, and touchdown, plus live health beacons over LoRa. GPS is kept external to keep the board lean and recovery flexible. ORCA III delivers tighter integration, better noise margins, and real time telemetry in a smaller form factor built for Ares flights.
