Windows 95, Windows Me, Windows XP, Windows 2000, Windows NT, Windows 98
Publisher's description of Celestia
Celestia is a space simulation that allows you to travel within the solar system, out to the stars, and beyond the Milky Way galaxy. Possible destinations include over 100,000 stars, nearly one hundred solar system destinations, and sixty recently-discovered extrasolar planets. Celestia uses OpenGL to render realistic real-time animations of space travel.