System Architecture

Overview

Spacecraft software architecture requires balancing competing demands: deterministic real-time performance under strict timing constraints, fault tolerance in an environment where hardware failures are inevitable, and optimal resource utilization where every byte of memory and every processor cycle counts.

FSW Engineering brings deep expertise in architecting flight software systems that meet these challenges. We design layered, modular architectures that enable rigorous verification, support safe mode operations, and provide the flexibility needed for mission-specific customization while maintaining the reliability required for spaceflight.

What We Deliver

01

Software Architecture Documents

Comprehensive architecture specifications defining system decomposition, interfaces, data flows, and design patterns.

02

Component Interface Definitions

Precise API specifications, data structure definitions, and protocol documentation for all software components.

03

Timing & Performance Models

Worst-case execution time analysis, schedulability studies, and resource utilization budgets.

04

Safety & Fault Tolerance Design

Fault detection and isolation strategies, redundancy management schemes, and safe mode architecture.

Architectural Approaches

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Layered Architectures: Clean separation between hardware abstraction, middleware, and application layers enabling portability and maintainability

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Component-Based Design: Modular architectures with well-defined interfaces supporting independent development and verification

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Real-Time Executive: Deterministic scheduling architectures including rate monotonic, time-triggered, and priority-based approaches

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Data-Centric Patterns: Publish-subscribe and data distribution service architectures for loosely-coupled subsystem integration

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Fault-Tolerant Designs: Redundancy management, watchdog architectures, and graceful degradation strategies

Key Design Considerations

Resource Constraints

Memory budgets (typically 1-100MB), processor limitations (10-200 MIPS), power constraints, and radiation-hardened component selection.

Real-Time Requirements

Hard deadlines for GN&C (ms-scale), soft deadlines for telemetry (100ms-1s), and background processing for housekeeping tasks.

Reliability & Availability

Single-event upset mitigation, autonomous fault recovery, and maintaining operations despite component failures.

Verification Complexity

Architecture choices that enable comprehensive testing, support formal verification methods, and facilitate certification.

Standards & Tools

Architecture development employs industry-standard modeling languages including SysML for system-level design. Core competencies include avionics network design for deterministic data exchange, payload design and integration, protocol engineering for reliable communication links, and data management architectures for telemetry and command processing. Command and telemetry database development follows XTCE (XML Telemetric and Command Exchange) standards to ensure interoperability with ground systems and mission operations centers.

XTCE (XML Telemetric and Command Exchange) is a standardized, non-proprietary information model and data exchange format