- Earth–Moon system (Wikipedia)
The Earth and the Moon form the Earth-Moon satellite system with a shared center of mass, or barycenter. This barycenter stays located at all times 1,700 km (1,100 mi) (about a quarter of Earth’s radius) beneath the Earth’s surface, making the Moon seemingly orbit the Earth.
- Space Shuttle: A Journey into Space (Wikipedia)
Space Shuttle: A Journey into Space is a space flight simulator game designed by Steve Kitchen for the Atari 2600 and published by Activision in 1983. It is one of the first realistic spacecraft simulations available for home systems. Space Shuttle was adapted to the Atari 8-bit computers and Atari 5200 by Bob Henderson (1984), then ported to the ZX Spectrum (1984), Commodore 64 (1984), Amstrad CPC (1986), and MSX (1986). The 1984 Activision Software catalog also mentions an Apple II version.