Event-Driven Simulation for Rapid Iterative Development of Distributed Space Flight Software

2025-05-18

AI Summary

To address the long development cycles and high verification costs associated with flight software for distributed space systems, this paper proposes a high-fidelity, event-driven simulation environment. Methodologically, it introduces a novel hybrid continuous-discrete event simulation architecture, integrating lightweight application-layer binary virtualization, real-time scheduling modeling, and embedded binary dynamic loading, alongside high-fidelity models of multi-spacecraft orbital dynamics, wireless communication, relative sensing, and inter-satellite protocols. The key contributions are: (1) achieving hardware-in-the-loop–level observability and fidelity within a pure software simulation environment; (2) enabling full-stack functional verification and quantitative performance evaluation; and (3) successfully supporting 33 months of iterative development for the VISORS mission’s GNC software and Stanford’s rendezvous-and-docking software package—significantly improving defect localization efficiency and navigation and control verification accuracy.

Technology Category

• Planning, Routing, and Scheduling: Mixed Discrete/Continuous Planning
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior
• Multiagent Systems: Agent-Based Simulation and Emergent Behavior

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Web Mining and Content Analysis: Web data generation and simulation

Abstract

This paper presents the design, development, and application of a novel space simulation environment for rapidly prototyping and testing flight software for distributed space systems. The environment combines the flexibility, determinism, and observability of software-only simulation with the fidelity and depth normally attained only by real-time hardware-in-the-loop testing. Ultimately, this work enables an engineering process in which flight software is continuously improved and delivered in its final, flight-ready form, and which reduces the cost of design changes and software revisions with respect to a traditional linear development process. Three key methods not found in existing tools enable this environment's novel capabilities: first, a hybrid event-driven simulation architecture that combines continuous-time and discrete-event simulation paradigms; second, a lightweight application-layer software virtualization design that allows executing compiled flight software binaries while modeling process scheduling, input/output, and memory use; and third, high-fidelity models for the multi-spacecraft space environment, including for wireless communication, relative sensing such as differential GPS and cameras, and flight computer health metrics like heap exhaustion and fragmentation. The simulation environment's capabilities are applied to the iterative development and testing of two flight-ready software packages: the guidance, navigation, and control software for the VISORS mission, and the Stanford Space Rendezvous Laboratory software kit for rendezvous and proximity operations. Results from 33 months of flight software development demonstrate the use of this simulation environment to rapidly and reliably identify and resolve defects, characterize navigation and control performance, and scrutinize implementation details like memory allocation and inter-spacecraft network protocols.

Problem

• Rapid prototyping and testing of distributed space flight software
• Combining software simulation flexibility with hardware-in-the-loop fidelity
• Enabling continuous improvement and cost reduction in flight software development

Innovation

• Hybrid event-driven simulation architecture combining paradigms
• Lightweight software virtualization for flight binaries execution
• High-fidelity multi-spacecraft environment modeling