A Unified Avionics Platform (OBC-Hyper-Polar & TCU) for Complex Space Missions in GEO

Modern orbital servicing spacecraft are expected to perform increasingly sophisticated operations, from deploying mechanisms and manipulating payloads to monitoring hundreds of sensors while maintaining exceptional reliability. Traditionally, these functions require multiple independent electronic units, increasing spacecraft mass, wiring complexity, integration effort, and overall mission risk.

To address these challenges, we have developed an integrated avionics architecture consisting of two tightly coupled companion boards:

• OBC-Hyper-Polar – A high-performance On-Board Computer 
• TCU – A dedicated actuator and sensor interface controller

Together, these computers provide a complete control and data acquisition solution capable of driving spacecraft mechanisms while simultaneously monitoring extensive spacecraft telemetry.

System Overview

The architecture is designed around a clear separation of responsibilities.

The OBC-Hyper-Polar serves as the spacecraft’s central computing platform, executing flight software, guidance and control algorithms, mission management, communications, and data handling.

The TCU acts as an intelligent distributed I/O subsystem responsible for:

• Stepper motor control
• Solenoid valve actuation
• High-voltage load switching
• Temperature acquisition
• Analog sensor conditioning
• Current monitoring
• Real-time actuator management

This modular approach allows the flight computer to focus on mission-level decision making while the TCU performs deterministic real-time hardware control.

High-Performance OBC-Hyper-Polar

At the core of the system is the PolarFire® SoC MPFS460T, combining:

• Quad-core 64-bit RISC-V processors
• FPGA fabric for deterministic hardware acceleration
• High reliability suitable for embedded aerospace applications

The OBC integrates:

• Multi-protocol communication interfaces
  • SpaceWire
  • Gigabit Ethernet
  • CAN
  • RS-422
  • RS-485
  • UART
• High-speed data acquisition
  • 16-channel 16-bit ADC
• High-capacity memory
  • 8 GB DDR4 ECC
  • 4 GB LPDDR4
  • Dual 256 GB eMMC storage
• Radiation-oriented memory
  • MRAM
• Dedicated Spacecraft Interfaces
  • Multiple BDM interfaces
  • ASM interfaces
  • Pressure acquisition
  • 28 V power input with DC/DC conversion

This combination enables the OBC to manage mission software, payload interfaces, spacecraft communications, and health monitoring simultaneously.

Intelligent Thermal & Control Unit

The companion TCU extends the OBC by providing comprehensive spacecraft I/O capabilities.

Stepper Motor Control

Many orbital servicing missions rely on precision mechanisms including:

• Capture systems
• Docking interfaces
• Instrument positioning
• Valve actuation
• Deployable structures

The TCU supports:

• 6 independent stepper motor H-bridges
• PMOS and NMOS power stages
• FPGA-based step sequence generation
• Deterministic motion control
• High positioning accuracy

Using FPGA-generated stepping sequences minimizes processor loading while ensuring highly repeatable motor operation.

Solenoid Valve Control

Fluid management systems frequently require reliable valve actuation.

The TCU includes:

• 4 high-current solenoid H-bridges
• Approximately 1.6 A peak drive capability
• Current sensing for health monitoring
• Fast and reliable valve operation

These outputs are suitable for:

• Propellant valves
• Pneumatic systems
• Release mechanisms
• Latching actuators

High-Power Switching

Orbital servicing spacecraft often operate numerous auxiliary loads.

The TCU integrates:

• 48 PMOS power output stages
• Individual current sensing
• PWM capability
• Approximately 10 A switching capability per channel

Typical loads include:

• Heaters
• Lamps
• Deployment devices
• Auxiliary electronics
• Custom spacecraft payloads

Per-channel current monitoring enables advanced fault detection and power management.