Walt Disney originally conceived the idea for Space Mountain in the mid 60’s, as a new thrill ride for Disneyland. The attraction was envisioned to be the focal point of Tomorrowland’s 1967 makeover.
But, Walt’s death, limited technology at the time, and space limitations in Disneyland, shelved the attraction for over a decade.
The idea for the ride was resurrected when the Magic Kingdom was looking for a thrill ride. Space Mountain opened on January 15, 1975, at a cost of around $20 million.