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.

Space Mountain in Walt Disney World celebrates 50 years of operation. Initially opening on January 15, 1975, Space Mountain, an indoor steel rollercoaster themed to space travel, has been a staple of Tomorrowland, the area of the Magic Kingdom park where the ride resides.

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.

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. Disney’s Magic Kingdom theme park will celebrate the 50th anniversary of Space Mountain on Wednesday, Jan. 15.

Space Mountain is one of the most recognizable theme park attractions around the world, but here’s what you may not know about the beloved ride.

• 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 Disney’s Magic Kingdom Park celebrates its 50th anniversary Wednesday and the park is set to celebrate. Throughout the night of January 15, the exterior of Space Mountain will bathed in a golden glow visible throughout the Magic Kingdom.