Project Apollo - NASSP (also known as NASSP or NCPP) is an add-on for the Orbiter space flight simulator. Project Apollo simulates the Apollo missions to Earth orbit and the Moon, and is slowly expanding to simulate planned post-Apollo missions that never flew. Project Apollo features a near-full implementation of the control panels in the Command Module and Lunar Module, and an increasingly accurate simulation of the internal systems (e.g. electrical distribution, fuel cells). Also the Virtual AGC software is supported, which allows you to run precisely the same on-board guidance software as used by the real Apollo Guidance Computer.
NASSP is intended to be a study simulator, as accurate as possible. While there are optional simplified implementations of the CMC/LGC and checklist assistance available, no attempt has been made to "game-ify" it or make it more accessible at the expense of realism. Original NASA software, documentation, and procedures have been used whenever and wherever possible. Our main goal is 100% accuracy at the systems level. If you want a more user-friendly or accessible simulation there are plenty of better options, both for Orbiter and for other platforms.
Orbiter is a Windows program, so this is a Windows-based project. You will need Microsoft Visual Studio 2015 (or newer) to build the project. Until someone ports Orbiter to other platforms (or produces an Orbiter-compatible simulator of sufficient capability) there's not much that can be done about this. Orbiter and NASSP might run under WINE, but we haven't made ensuring this a project priority.
For more information, see our forums. To contribute, see the developer installation instructions. Releases will be provided as ZIP files to be unzipped into an existing Orbiter installation as is usual for Orbiter addons.