Spacecraft Simulators

High-fidelity hardware, software-only, and hardware-in-the-loop simulation environments.

High-Fidelity Spacecraft Simulators

EFSI maintains that a high-fidelity spacecraft simulator is foundational to developing a low-cost, low-risk ground system and flight software suite. Our simulators provide a comprehensive, hardware-equivalent environment used for mission simulations, training, procedure validation, and end-to-end flight software development.

We support three simulation approaches — Software-Only, Hardware-in-the-Loop (HWIL), and Digital Twin via FOGI-Lake — giving missions the flexibility to choose the right fidelity level for each phase of development.

Runner-up, NASA Software of the Year

JWST Mirror

Simulation Environments

Software-Only

Cost-effective simulation for development, testing, and training without physical hardware. Runs unmodified flight software with register-level device models for maximum fidelity.

Hardware-in-the-Loop (HWIL)

Integrates actual flight hardware for system-level validation. Supports MIL-STD-1553, SpaceWire, and RS-422 bus simulation with real-time dynamic models.

Digital Twin via FOGI-Lake

Containerized Digital Twin (equivalent to a hardware flatsat). Integrates flight dynamics, power, thermal, and instrument simulations into a single, rapidly deployable ecosystem.

Explore FOGI-Lake

Integrated Dynamic Simulation Ecosystem

Real-time, high-fidelity dynamic model integration across all simulation environments.

Seamless Model Integration

Our architecture allows for the integration of diverse simulator products — including the Goddard Dynamics Simulator (GDS) and Northrop Grumman's Virtual Development Suite (VDS) — with minimal code changes. Robust interface libraries enable cross-platform compatibility and bit-for-bit parity.

End-to-End Validation

Our simulators support all mission phases, providing real-time models for GN&C, flight-to-ground communication (DTN), and spacecraft-level integration across software-only and HWIL configurations.

QEMU & Simics Processor Models

Target architecture simulation using QEMU and Wind River Simics, enabling unmodified flight software execution on accurate processor models.

Development & Debug Tools

Save and restore simulation states for repeatability, fault injection for full code coverage, and operator training scenarios for mission readiness.

Proven Mission Heritage

EFSI has developed and integrated simulators for over 20 GSFC missions.

Current Leadership

We currently provide dynamic simulation support for the Roman Space Telescope and PACE (Goddard Dynamics Simulator support).

Heritage Successes

Developed and supported simulators for GPM, DSCOVR, JWST, and LRO. For JWST, we successfully integrated a high-fidelity dynamic simulator with a software-only environment to support long-term sustaining engineering and operations.

Mission Simulator Portfolio