User Summary Orbiter is a FREE and realistic space flight simulation program for the Windows PC. Designed by Dr. Martin Schweiger, Orbiter is a real-time 3D spaceflight simulator. It is one of the most robust public-access spaceflight simulators, and the program is designed to engage less experienced users. Orbiter realistically emulates the physics of space travel, and is accurate enough to recreate historic space voyages. The program allows for fictional spacecraft to be used well, and these craft can present easier flight controls for new users. The Orbiter exploration zone spans the entire solar system and includes the Sun, the eight planets, and all major moons. Smaller objects such as comets, asteroids, and dwarf planets are not included in the base program. The flight simulator permits sub-orbital, orbital, and interplanetary maneuverability. A time compression option is included to reduce dead time in longer voyages. The simulator is very flexible, and a large amount of user-created content is available for download. Material includes custom spacecraft, minor bodies that exist in our solar system, new Multi-Function Displays (MFDs), and even complete solar systems (both real and fictional). A scenario editor is available which allows players to design missions that make use of custom vessel capabilities. See the Web Links section below for the Orbiter download link.