The opening of Walt Disney World’s Space Mountain in 1975 was attended by a host of real astronauts, one of whom had been to the moon.
Among the guests at the inaugural event were Jim Irwin, who walked on the lunar surface during the Apollo 15 mission; Gordon Cooper, the first man to spend a whole day in space during Mercury 9; and Scott Carpenter, whose post-Sputnik journey into space on Mercury 7 was watched by 40 million captivated Americans. None of them left any record of what they thought of the ride.
Gordon Cooper had been working as a WED Imagineer, and was VP of Research and Development for Epcot prior to assisting in developing and opening Space Mountain. He had a huge hand in its early development and always remained a big fan of the attraction. Fun fact: Two of his youngest daughters became Disney Cast members, themselves, and ended up working a season at Space Mountain.