Athena: Building a High-Performance 6-Layer PCB for Rocket Avionics

Advanced rocketry requires a flight computer to bring together processing, sensing, communication, power management, and control within a compact and reliable hardware platform. Athena, an open-source flight computer project by NotARoomba, addresses these requirements with a triple-MCU architecture, redundant sensing, multiple communication interfaces, dedicated control channels, and a 6-layer PCB.

The Athena board measures 80 × 140 mm and integrates three STM32 MCUs, three IMUs, barometers, GNSS, LoRa, Bluetooth, CAN, USB, flash storage, an SD card interface, and multiple power-management functions. The project was designed in EasyEDA, with JLCPCB credited for PCB manufacturing and assembly. This case study looks at how the design combines dense functionality with a multilayer PCB architecture and how professional PCB manufacturing supports the transition from an open-source design to physical hardware.

Project Highlights

Athena is a good example of a high-performance embedded PCB in which multiple functional blocks must coexist on a relatively compact board. Rather than treating processing, sensing, communication, power, and control as isolated circuits, the design brings them together into one multilayer platform.

Why Athena Uses a 6-Layer PCB

The Athena project combines three MCUs with multiple sensors, communication modules, storage, power conversion, and dedicated control channels. Accommodating these functions on an 80 × 140 mm board requires more routing capacity and a more organized layer structure than a simple two- or four-layer design would provide.

More Routing Capacity

A 6-layer PCB provides additional routing resources for connecting the three processing units, sensors, communication interfaces, storage devices, and control circuitry. The extra layers help distribute connections across the board instead of forcing every signal onto a small number of crowded routing surfaces. For a design with several digital interfaces and multiple functional blocks, this additional routing capacity is important for keeping connections organized and making the layout more manageable.

Organized Power Distribution

Athena operates from a 7.4–12 V LiPo input while generating regulated 5 V and 3.3 V rails. The design also includes dedicated power-management devices for battery charging, USB-C power delivery, and servo power. A multilayer architecture can provide more structured power distribution and clearer separation between power and signal routing, helping the designer manage the relationships between different functional sections.

Improved Signal Organization

The flight computer contains multiple high-speed digital interfaces and several sensor connections. A multilayer PCB allows signal routing to be organized across more layers while maintaining reference structures between routing regions. This makes it easier to plan signal paths and reduce unnecessary routing congestion as the design grows in complexity.

Compact Functional Integration

The 80 × 140 mm board integrates processing, sensing, communications, storage, power, and control functions in one hardware platform. Using six layers gives the design more freedom to place these functions efficiently while keeping the overall board footprint compact.

JLCPCB supports 6-layer PCB manufacturing for high-density and mixed-signal designs, with options including controlled impedance and Via-in-Pad for applicable designs. These are manufacturing capabilities available for suitable projects; they should not be interpreted as specific processes used by Athena unless confirmed by the project files.

A Triple-MCU Architecture for Distributed Processing

One of Athena's defining features is its triple-MCU architecture. Instead of assigning every task to a single microcontroller, the project separates processing responsibilities across three STM32 devices. This creates a clear functional division between sensor processing, telemetry and storage, and control functions.

One of Athena's defining features is its triple-MCU architecture.

The MPU handles sensor-related computation and Kalman filtering, while the TPU manages communication and data storage. The SPU is dedicated to pyro and PWM functions. This division places several independent processing blocks on the same PCB, which increases the importance of organized placement and routing.

Athena also provides six pyro channels and six PWM channels, with two PWM channels intended for TVC and four for fin control. These dedicated interfaces add another layer of functional requirements to the PCB layout, because control signals and their associated power and interface circuitry must coexist with the processing and sensing sections.

Redundant Sensors for a More Capable Flight Computer

Reliable flight-control hardware depends on accurate sensing. Athena includes three ICM-45686 IMUs, a LIS2MDLTR magnetometer, and two barometer devices, the ICP-20100 and BMP388. This combination gives the flight computer access to multiple sources of motion, orientation, and atmospheric-pressure information.

Athena Sensor Configuration

• 3 × ICM-45686 IMUs for inertial sensing
• LIS2MDLTR magnetometer
• ICP-20100 and BMP388 barometers

With several sensor devices connected to the processing architecture, the PCB must accommodate multiple signal connections while keeping the sensor area practical for routing and placement. The 6-layer structure gives the designer additional routing resources for these connections and helps integrate the sensing section with the three-MCU processing system.

For a professional PCB manufacturing workflow, the goal is not simply to fit every component onto the board. The layout must also translate into a manufacturable design with appropriate spacing, routing, drilling, and layer construction. JLCPCB's multilayer manufacturing capabilities are designed to support this type of complex PCB architecture.

Power Management Within the 6-Layer PCB

Athena's power system has to support both the flight computer's digital electronics and its control-related functions. The project accepts a 7.4–12 V LiPo input and includes dedicated devices for charging, USB-C PD, servo power conversion, and regulated low-voltage rails.

The presence of several power-management blocks makes power distribution an important part of the PCB architecture. The charger, USB-C power-delivery controller, servo buck converter, and low-voltage regulator each serve different roles, so their placement and interconnection need to be considered together with the rest of the board.

On a multilayer PCB, a structured layer stack can make power and ground distribution easier to organize. JLCPCB offers 6-layer stackups and multilayer fabrication options for designs that require dedicated power and signal-routing structures.

Multiple Communication Interfaces on One PCB

Athena combines several communication technologies on the same flight computer, allowing the platform to communicate with external systems and connect to different onboard functions. The communication section includes GNSS, LoRa, Bluetooth, CAN, USB, and dedicated UART channels.

Integrating these interfaces increases the number of connections that must be routed between modules and the three MCUs. The design therefore benefits from a PCB architecture that provides sufficient routing capacity while maintaining a clear relationship between communication, processing, power, and control sections.

The result is a highly integrated flight computer rather than a collection of separate boards. This type of integration is one reason multilayer PCB manufacturing is commonly used for advanced embedded hardware with many interconnected functions.

From Design Challenges to PCB Manufacturing Requirements

From design challenges to PCB manufacturing requirements.

The table above connects Athena's design characteristics with the manufacturing considerations that commonly accompany a dense multilayer PCB. These are general engineering relationships rather than claims that every listed manufacturing feature was specifically used on Athena.

For an open-source hardware project, manufacturing readiness is especially important because a successful design must move from CAD data to repeatable physical hardware. The PCB manufacturer therefore needs to support the required layer count, materials, fabrication tolerances, and assembly process while maintaining consistency across production.

From PCB Design to Manufactured Hardware

Athena was designed using EasyEDA, while the project credits JLCPCB for PCB manufacturing and assembly. This makes the project a practical example of how an open-source PCB design can progress from schematic and layout work to physical hardware.

6-Layer PCB Manufacturing

JLCPCB supports 6-layer PCB manufacturing with multilayer stackup options suitable for high-density, high-speed, mixed-signal, and other advanced applications. Current 6-layer capabilities include FR-4 constructions, controlled impedance options, and Via-in-Pad processes for applicable designs.

Controlled Impedance and Advanced Interconnect Options

For designs that require tighter signal-integrity control, JLCPCB provides controlled-impedance manufacturing options across supported multilayer constructions. Via-in-Pad is also available for applicable designs, helping designers address routing density around compact component footprints. These capabilities are presented here as JLCPCB manufacturing options and are not claimed as specific features of the Athena board.

PCB Assembly for Integrated Hardware

Once the fabricated board is ready, assembly becomes another important part of bringing a complex flight computer to life. JLCPCB provides PCB assembly services covering SMT and THT requirements across supported board constructions, with inspection capabilities that help support production quality. The exact assembly process depends on the project's component packages, board construction, and production requirements.

Bringing an Open-Source Flight Computer to Life

• Processing: Three STM32 MCUs divide sensor processing, telemetry/storage, and control responsibilities.
• Sensing: Multiple IMUs, a magnetometer, and barometers provide the flight computer with diverse sensor inputs.
• Communication: GNSS, LoRa, Bluetooth, CAN, USB, and UART interfaces connect the system to external and onboard functions.
• Power: Battery charging, USB-C PD, servo power conversion, and regulated rails are integrated into the same PCB.
• Control: Six pyro channels and six PWM channels support dedicated control functions.

Processing: Three STM32 MCUs divide sensor processing, telemetry/storage, and control responsibilities.

The strength of Athena lies in the integration of these functions. Each block has its own requirements, but the final product must operate as one coordinated flight computer. The 6-layer PCB provides the physical platform that brings these circuits together while maintaining a compact 80 × 140 mm form factor.

What This Project Demonstrates

1. Multilayer PCB Design

Athena demonstrates how a 6-layer PCB can provide the routing and layer-organization resources needed for a complex embedded system. With three MCUs, multiple sensors, communication interfaces, storage, power-management circuits, and control channels, the design illustrates why layer count becomes an important architectural consideration as hardware functionality increases.

2. Functional Integration

Instead of distributing flight functions across several independent boards, Athena integrates processing, sensing, communication, power, and control into one PCB. This approach can simplify the overall hardware architecture while increasing the importance of careful placement, routing, and manufacturing preparation.

3. Hardware Redundancy

The use of multiple IMUs and multiple processing units reflects a design approach that gives different functions dedicated hardware resources. In an advanced embedded system, such architectural separation can help organize computational and control workloads across the board.

4. Manufacturing Readiness

The project credits JLCPCB for manufacturing and assembly, showing the complete path from an open-source EasyEDA design to physical hardware. For complex PCB projects, a capable manufacturing partner is an important part of turning a sophisticated layout into a practical, assembled product.

FAQ about Athena 6-Layer PCB

Conclusion on Athena 6-Layer PCB

Athena is a strong example of a high-performance 6-layer PCB designed for an advanced flight-computer application. Its 80 × 140 mm board integrates three STM32 MCUs, multiple sensors, GNSS, LoRa, Bluetooth, CAN, USB, storage, power management, and dedicated pyro and PWM control channels.

The project also demonstrates the value of connecting PCB design decisions with manufacturing requirements. As board functionality and routing density increase, a well-planned multilayer structure and a capable PCB manufacturing and assembly partner become increasingly important. With its 6-layer PCB manufacturing, multilayer fabrication, controlled-impedance options, Via-in-Pad capability, and PCB assembly services, JLCPCB provides manufacturing options that can support a wide range of advanced PCB designs.

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