From 1973 until 1994 Space Mountain was sponsored by RCA. Guests entered Space Mountain through an entrance building located in Tomorrowland. The Building had three large RCA logos as well as a original "four seat" ride vehicle encased in a clear case. Inside the vehicle sat a family. Before guests entered the "entrance portal", they would pass a large quote on the wall which read:
{{Quotation|"ONE GIANT STEP... Dedicated to the men and women whose skills, sacrifice, courage and teamwork opened the door to the exploration of man's exciting new frontier...outer space. Because they dared to reach for the stars and the planets, man's knowledge of his universe, earth and himself has been greatly enriched. Presented by missile, space and range pioneers. January 15, 1975."}}
Just after entering the building, guests boarded a descending moving ramp. On the right side of the ramp, guests could see RCA's logo, Nipper the Fox Terrier inside a flying saucer. At this point in the attraction RCA's Space Mountain theme song- "Here's To The Future And You" began to play. Further down the ramp guests could look out convex windows and see the Star Corridors, a series different space themed displays. One display for example, showed an astronaut riding his moon buggy in space.