A cultural touchstone, the dark ride opened to the public on Jan. 15, 1975, three years and three months after the Magic Kingdom’s debut.

When the ride opened on Jan. 15, 1975, an Apollo moonwalker was its first passenger, NASA's insignia was on display and Space Mountain was dedicated to opening the new frontier.

• Jan. 15, 1975: Space Mountain opened at a cost of $15 million, the Sentinel reported, “an amount more than the whole cost of Disneyland, built in 1955.” Astronauts Scott Carpenter, James Irwin and Gordon Cooper posed with Mickey Mouse, who is decked out in a spacesuit.

Space Mountain in Walt Disney World celebrates 50 years of operation. Initially opening on 1975, Space Mountain, an indoor steel rollercoaster themed to space travel, has been a staple of Tomorrowland,

Walt Disney wanted to build Space Mountain at Disneyland a decade before the indoor roller coaster forever altered the skyline of the Magic Kingdom a few years after the debut of the Florida theme park.