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JSTAR Simulation

To provide the NASA IV&V Program with the means to verify and validate various mission elements through Independent Testing in the form of dynamic analysis, JSTAR creates software-only simulation environments that emulate the hardware of the mission, and—through their own developed technology known as the NOS Engine (NASA Operational Simulation Engine)—integrates its simulation software.

Hardware Emulation

In the first step of their simulation development, JSTAR begins a process known as hardware emulation. This technique enables a computer system, such as a standard desktop, server, or laptop, to behave like or imitate another computer system. For example, hardware emulation is apparent in video game production—where console/arcade hardware is emulated to allow playing original games in the emulation environment. Likewise, NASA flight computers are often comprised of highly custom and specialized hardware, unlike typical consumer computers. Hardware emulation and custom device modeling allow JSTAR to run unmodified flight software binaries from NASA in their own emulated environments, communicating with supporting hardware as they would in flight. In other words, JSTAR creates their own model of flight computers from NASA missions that will run in their own standalone environment, with the software behaving the same as it does in its original hardware environment.

NOS Engine


Next, the JSTAR-produced NOS Engine comes into play as a tool for simulation integration. The NASA Operational Simulation (NOS) Engine is a message passing middleware designed specifically for use in simulation. JSTAR developed this software to provide future products with the means for component integration—allowing multi-part systems to get the opportunity to send messages back and forth despite incompatible software. This kind of integration paired with advanced features like time synchronization, data manipulation, and fault injection, allows NOS Engine to provide a fast, flexible, and reusable system for connecting and testing various pieces of a simulation.

Simulation Integration

Finally, JSTAR works to integrate each component of mission flight software through a process known as simulation integration, incorporating the communication and timing attributes of NOS Engine throughout the multi-component system. In their integration process, the JSTAR team typically combines a diverse set of simulations to develop a single, integrated product. Simulations may be an integration of the following:

  • hardware simulator ported to software using virtual buses
  • software simulator with unique Operating System requirements executed within a virtual machine
  • dynamic engines tuned to a specific mission’s properties
  • running flight software within a virtualized CPU and interfaces

The final product of all of this is a JSTAR-developed, software-only simulator, equipping the NASA IV&V program with the ability to independently test, verify, and validate mission elements as well as entire missions without the use of hardware—saving time, money, resources, and increasing safety for NASA.