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NASA Operational Simulator for Small Satellites

The NASA Operational Simulator for Small Satellites (NOS3) is a suite of tools developed by NASA's Katherine Johnson Independent Verification and Validation (IV&V) Facility to aid in areas such as software development, integration & test (I&T), mission operations/training, verification and validation (V&V), and software systems check-out. NOS3 provides a software development environment, a multi-target build system, an operator interface/ground station, dynamics and environment simulations, and software-based models of spacecraft hardware.


The best source of documentation can be found at the wiki or NOS3.


Each of the applications listed below are required prior to performing the installation procedure:


  1. Clone the repository git clone
  2. cd nos3
  3. Clone the submodules git submodule update --init --recursive
  4. Run vagrant up and wait to return to a prompt
    • This can take anywhere from a few minutes to hours depending on internet speeds and host PC specs
  5. Login to the nos3 user using the password nos3123! and get to work!
  6. Try building and running following the instructions below

Getting started

By default the nos3 repository is shared into the virtual machine at /home/nos3/Desktop/github-nos3

  1. Open a terminal
  2. Navigate to the nos3 repository
  • cd /home/nos3/Desktop/github-nos3
  1. To build use the make command from the nos3 repo
  2. To run nos3 use the make launch command from the nos3 repo
  3. To halt nos3 use the make stop command from the nos3 repo

Directory Layout

  • components contains the repositories for the hardware component apps; each repository contains the app, an associated sim, and COSMOS command and telemetry tables
  • fsw contains the repositories needed to build cFS FSW
    • /apps - the open source cFS apps
    • /cfe - the core flight system (cFS) source files
    • /nos3_defs - cFS definitions to configure cFS for NOS3
    • /osal - operating system abstraction layer (OSAL), enables building for linux and flight OS
    • /psp - platform support package (PSP), enables use on multiple types of boards
    • /tools - standard cFS provided tools
  • gsw contains the nos3 ground station files, and other ground based tools
    • /ait - Ammos Instrument Toolkit (Untested for 1.05.0)
    • /cosmos - COSMOS files
    • /OrbitInviewPowerPrediction - OIPP tool for operators
    • /scripts - convenience scripts
  • sims contains the nos3 simulators and configuration files
    • /cfg - 42 configuration files and NOS3 top level configuration files
    • /nos_time_driver - time syncronization for all components
    • /sim_common - common files used by component simulators including the files that define the simulator plugin architecture
    • /sim_terminal - terminal for testing on NOS Engine busses
    • /truth_42_sim - interface between 42 and COSMOS to provide dynamics truth data to COSMOS


We use SemVer for versioning. For the versions available, see the tags on this repository.


This project is licensed under the NOSA (NASA Open Source Agreement) License.

Issues and Features

Please report issues and request features on the GitHub tracking system - NOS3 Issues.


If this project interests you or if you have any questions, please feel free to contact any developer directly or email