Space Mountain is an indoor, space-themed roller coaster in Tomorrowland at Disneyland in Anaheim, California. Opened on May 27, 1977, it was the second roller coaster built at Disneyland, and was the second of the five versions of Space Mountain built by The Walt Disney Company. Its exterior façade is one of Disneyland's four "mountain" structures that serve as park landmarks.
Walt Disney originally conceived the idea of a space-themed roller coaster for Disneyland following the success of the Matterhorn Bobsleds, which opened in 1959. However, a number of factors including lack of available space, Walt Disney's death, and the Disney company's focus on building what would become Walt Disney World led to the project's postponement in the late 1960s. After the early success of the Magic Kingdom park at Walt Disney World, Disney revived the Space Mountain project and opened the first Space Mountain at the Magic Kingdom in 1975. Soon after, Disney began plans to build a smaller version of Space Mountain at Disneyland, and opened Disneyland's Space Mountain in 1977. The design of Disneyland's Space Mountain was replicated at Tokyo Disneyland in 1983 and Hong Kong Disneyland in 2005; the Tokyo version was significantly changed in 2006 to become more similar to the refurbished 2009 Magic Kingdom version.
Space Mountain has undergone a number of major upgrades and refurbishments over the years, including the addition of an onboard soundtrack in 1996, repainting of the exterior in 1997 and 2003, and a complete replacement of the original track and ride vehicles from 2003 to 2005. It has also been given a third roof up the mountain during late 2013 and early 2014. Every September and October during Halloween Time at Disneyland, starting in 2009 and ending in 2019, the dome was given projections for the Ghost Galaxy event. On November 16, 2015, Space Mountain was given a new overlay and theme in anticipation for Star Wars: The Force Awakens and redubbed "Hyperspace Mountain." Since then, the attraction has switched between the original and "Hyperspace Mountain" Star Wars theme several times.