This question, What are the uses of the NASA core Flight System (cFS)?, while perhaps too broad and perhaps not well written, was in my opinion closed far too early.
Flight software is a huge component of the cost of a new space vehicle. cFS has the potential to be a huge game changer in how we write flight software. Open source (e.g., Linux, Python, numpy/scipy, NetCDF, OpenCL, OpenGL, OpenVDB, Blender, CMake, VTK, ...) has drastically changed how software (and scientific software) is written and used. cFS is one of the shining lights in NASA's late entry into the open source game.