LEAPFROG is a terrestrial prototype developed as a testbed for lunar exploration vehicle technologies. Designed to operate under Earth’s gravity and atmosphere, the system supports repeated vertical takeoffs and landings, enabling the testing of avionics, control logic, and structural systems intended for extra-planetary missions. It features a modular architecture with an embedded real-time control layer for flight functions and a coordination interface for system management and ground station communication.

The control architecture consists of a dual layer software stack combining a microcontroller-based real-time control layer with a Linux-based coordination interface. The embedded layer executes time-critical control functions, including attitude stabilization using electric ducted fans, gimbal thrust vectoring, and throttle regulation with LIDAR-based altitude feedback. Subsystems operate as independent real-time tasks to ensure deterministic execution and fault isolation. The coordination layer manages telemetry streaming, system state management, and serial communication with a heartbeat protocol that maintains synchronized command and telemetry exchange between layers.

Embedded control layers are supported by an STM32 microcontroller, selected for its processing speed, extensive peripheral interface options, and onboard memory capacity. These capabilities support concurrent real-time execution of key subsystems such as attitude control, engine throttle regulation, and telemetry handling without resource contention. The microcontroller interfaces with redundant inertial measurement units, a LIDAR-based altimeter, and thrust vectoring actuators through I2C, PWM, and UART peripherals, providing tight integration with flight-critical hardware and supporting real-time sensor fusion. This platform offers low-latency access to sensors and actuators and supports the deterministic timing required for safe closed-loop control in real-world testing environments.

ROS publisher and subscriber nodes provide asynchronous control between the coordination layer, hosted on a Raspberry Pi, and the ground station computer. Commands transmitted from the ground station over a long-range serial radio link are decoded onboard the Pi and forwarded as structured control messages to the STM32 microcontroller. Telemetry data from the STM32 flows in the reverse direction and is republished for real-time monitoring and logging. This architecture supports autonomous routines and operator-driven workflows, maintains synchronization across system layers, and enables remotely coordinated test operations.

LEAPFROG is designed to serve as a scalable platform for validating real-time embedded flight software, control strategies, and coordinated system behavior in a terrestrial environment. Its modular architecture enables subsystem reconfiguration and scripted test execution without structural redesign. Unlike traditional aerospace test beds, LEAPFROG supports repeatable testing without reliance on consumables such as pressurized gas systems or large-scale fuel storage, significantly reducing operational cost and complexity. This practical approach reduces the barrier to entry for prototyping and evaluating embedded control solutions relevant to future planetary lander missions.