Command & Data Handling
Command_Data_Handling_System
The Command and Data Handling system is an 85-kilogram distributed computing network housed in radiation-shielded aluminum enclosures that manages sensor fusion, telemetry collection, and autonomous decision-making across a 100-year uncrewed mission. Consuming 150 watts with a processing throughput of 2,000 MIPS, the hardware operates in an environment subject to thermal cycling between -180 °C and +120 °C, 14-day lunar nights requiring low-power hibernation, and absent GPS signals. The radiation environment causes single-event effects from galactic cosmic rays and solar particle events, alongside an accumulated 100-year total ionizing dose of approximately 100 krad behind shielding. To maintain operations without human intervention, the architecture utilizes triple modular redundancy and electronics rated to 300 krad total ionizing dose tolerance.
Central nervous system of the Lunar Ark providing all command, data handling, processing, sensor fusion, and autonomous decision-making capabilities for 100-year uncrewed operation.
Purpose
Provide radiation-hardened computing infrastructure that processes all sensor data, executes autonomous decisions, manages subsystem coordination, and maintains operational continuity without human intervention for a century-scale mission on the lunar surface.
Context
The Lunar Ark must operate autonomously for 100 years in a GPS-denied, high-radiation lunar environment with intermittent or no Earth contact. CDH is the single most critical electronic system: every other subsystem depends on it for command execution, telemetry collection, fault detection, and mission planning. The system must self-heal, self-update, and gracefully degrade across a century of thermal cycling, radiation exposure, and component aging.
Principles
- ▸Triple Modular Redundancy (TMR) for all critical processing paths
- ▸Radiation hardening by design (RHBD) and radiation hardening by process (RHBP)
- ▸Byzantine fault tolerance for distributed consensus
- ▸Graceful degradation: system continues with reduced capability rather than failing
- ▸Separation of concerns: safety-critical functions isolated from non-critical
- ▸Deterministic real-time scheduling for time-critical operations
- ▸Autonomy levels from fully scripted to goal-directed AI planning
Typical implementations
- ▸RAD750/RAD5500 class radiation-hardened processors (BAE Systems heritage)
- ▸LEON4/GR740 SPARC-V8 processors (ESA/Cobham Gaisler heritage)
- ▸Vorago Technologies ARM Cortex-M rad-hard microcontrollers for edge nodes
- ▸MIL-STD-1553B command/response bus for critical paths
- ▸SpaceWire (ECSS-E-ST-50-12C) for high-speed data transfer
- ▸Time-Triggered Ethernet for deterministic networking
- ▸RTEMS, VxWorks, or FreeRTOS for real-time operating systems
- ▸cFS (core Flight System) NASA open-source flight software framework
Lunar considerations
- ▸Total ionizing dose (TID) accumulation over 100 years: ~100 krad behind shielding
- ▸Single-event effects (SEE) from galactic cosmic rays and solar particle events
- ▸Extreme thermal cycling: -180C to +120C between lunar day/night
- ▸14-day lunar night requires low-power hibernation modes
- ▸Regolith dust infiltration risk to connectors and thermal interfaces
- ▸No GPS: all timing from internal atomic clocks and Earth-synced references
- ▸Communication latency to Earth: 1.3s one-way minimum
- ▸Component obsolescence management over 100-year operational life
Specifications
Functional
| primary function | Provide centralized and distributed command, data handling, sensor fusion, and autonomous decision-making for all Lunar Ark subsystems |
| inputs | Telemetry from all L1 subsystems (analog and digital sensor data), Commands from Earth via L1-COM uplink, Navigation and positioning data from L1-NAV, Power system status from L1-PWR and L1-PDM, Radiation environment data from L1-RAD, Knowledge base queries from L1-KMS, Fault reports from L1-SLF |
| outputs | Command signals to all L1 subsystems, Telemetry downlink packets to L1-COM for Earth, Processed sensor fusion state vectors, Autonomous mission plans and schedules, Fault detection/isolation/recovery (FDIR) commands, Data archival streams to L1-DVT, Health and status reports |
| processing throughput mips | 2000 |
| command latency ms | 10 |
| telemetry collection rate hz | 100 |
| sensor fusion update rate hz | 10 |
| autonomous decision cycle s | 60 |
| data bus bandwidth mbps | 200 |
| system availability percent | 99.999 |
| radiation tolerance krad tid | 300 |
Physical
| mass kg | 85 |
| dimensions | Multiple distributed units; main CDH enclosure approx 0.6m x 0.5m x 0.4m |
| materials | Radiation-shielded aluminum-6061-T6 enclosures, Tantalum and tungsten spot shielding for sensitive ICs, Polyimide flex cables (Kapton), Gold-plated hermetic connectors, Conformal coating (Parylene-C) on PCBs |
| operating temp c | -40 to +85 (with active thermal control) |
| survival temp c | -55 to +125 |
| radiation environment | Lunar surface GCR and SPE, ~100 krad TID over 100 years behind shielding |
| vacuum | True |
| dust protection | IP6X equivalent hermetic sealing |
Operational
| power consumption w | 150 |
| power consumption sleep w | 15 |
| thermal range c | -40, 85 |
| lifetime years | 100 |
| mtbf hours | 500000 |
Interfaces
Provides
- Formatted telemetry data for Earth downlink and command distribution from Earth uplink. Includes housekeeping, science, and event data.
- Computational resources for navigation algorithms, map database hosting, and coordinate frame management.
- Load shedding commands, power mode transitions, and energy budget enforcement based on mission priorities.
- Switch commands for power distribution units, circuit breaker management, and load priority tables.
- High-level task assignments, path plans, and coordination commands for robotic fleet operations.
- System health assessments, anomaly flags, and fault recovery action commands to self-healing subsystem.
- Time-stamped telemetry, event logs, science data, and operational records for long-term storage.
- Read/write access to knowledge management system for procedures, configurations, and learned behaviors.
- Commands to activate radiation sheltering protocols based on space weather monitoring and dose predictions.
- Universal command/telemetry interface for every subsystem in the Lunar Ark. CDH is the central hub for all data flow.
Requires
- Uninterruptible critical bus power at 28V and 5V/3.3V regulated rails. CDH is highest-priority power consumer.
- Managed power feeds with overcurrent protection and remote switching capability.
- Uplink commands from Earth ground stations and acknowledgment of downlink telemetry.
- Lunar reference frame coordinates, robot positions, and precision timing for data timestamping.
- Real-time dose rates, particle flux measurements, and solar storm warnings for protective action decisions.
- Active thermal regulation to maintain CDH electronics within operating temperature range across lunar day/night.
- Component health reports, degradation trends, and recommended maintenance actions.
- Operational procedures, configuration parameters, and mission knowledge for autonomous decision-making.
Decomposes into
Cite this entry
Lunar Ark Codex. "Command & Data Handling" (L1-CDH). Retrieved 10 September 2026, from https://lunarark.com/entry/L1-CDH
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.