Project Apollo for Orbiter
NASA's Apollo Space Simulation Project is an Addon for Orbiter which recreates the Apollo missions.
Background
NASSP was originally developed by Jean-Luc Rocca-Serra, who released the source code to version 4.x. Mark Grant then rewrote the code as C++, added an initial C++ implementation of the Apollo Guidance Computer and replaced the control panel bitmaps, releasing 'NASSP COSTAM' and a derivative which provided basic support for the Virtual AGC software.
Jean-Luc released NASSP 5.0, an updated version based on that source code, for the next release of Orbiter, including, for example, new particle exhaust support and a Skylab launch module.
With the 6.x release it became Project Apollo for Orbiter, an open source Apollo simulation add-on. The latest 'stable' version is 6.4.3.
The 7.0 release is currently in Beta, including a near-complete simulation of the Command Module control panel and most of the internal systems, and support for new spacecraft. It is also capable of flying most of an Apollo mission using the Virtual AGC software.
Supported spacecraft
Lunar Module
Two-stage lander used to land astronauts on the Moon and return them to orbit.
Saturn V
Three-stage launcher used to launch a Command/Service Module and Lunar Module towards the Moon.
Saturn 1b
Two-stage launcher used to launch a Command/Service Module into Earth orbit.
Saturn INT-20
Two-stage launcher used to launch a Command/Service Module and larger payload into Earth orbit.
External links