Most Space Age structures weren’t built to last. Despite the massive technological advances that they represent, there’s no preservation plan in place for sites like the Santa Susana Field Laboratory in Southern California, where some of NASA's first rocket tests were conducted. Over sixty years after the first satellite entered Earth’s orbit and half a century since Apollo 11 landed on the face of the moon, preservationists and space lovers are facing a tough question—how do they ensure that these sites will stick around to evoke a sense of wonder in future generations?

This question is at the center of The Final Mission: Preserving NASA’s Apollo Sites, a book by Beth Laura O’Leary, Milford Wayne Donaldson, and Lisa Westwood. O’Leary and Westwood are both archaeologists, while Donaldson served as the California State Historic Preservation Officer for a decade. Although they acknowledge that there were thousands of people and hundreds of sites working in tandem to ensure the success of a manned mission to the moon, the book primarily focuses on places in California and New Mexico.

“These sites are difficult, in many respects, because they’re very technological,” says O’Leary. Once a moon mission site’s original use has been exhausted or retired, the technology can be difficult to re-purpose. Structures like Launch Complex 39 at NASA’s Kennedy Space Center in Cape Canaveral, Florida—which was originally built for the Apollo missions, and later put into use for the space shuttle program—are the exception, not the rule. Many structures don’t make it to the 50 year mark, the milestone which makes them eligible for recognition in the eyes of historic preservation law.

“These facilities that are built are not your typical facilities that we think, in historic preservation, of saving,” says Donaldson. “Some of the earlier space installations were designed by signature architects, but all of the buildings of the Cold War were simply not that.” Many of them were made of metal, corrugated tin, and concrete, and used for testing rockets and other equipment. They don’t have a lot of aesthetic appeal, but nevertheless, they tell an important story about space technology in the 20th century.

One of O’Leary’s passions is the protection of United States historic sites on the moon itself—sites that currently have no formal protections, and may be threatened in the future by another country’s space mission or a spacecraft launched by a private company, like Elon Musk’s SpaceX.

Per the Outer Space Treaty of 1967, no nation can appropriate space on a celestial body, and efforts to list the original 1969 Apollo 11 lunar landing site on even the U.S.'s National Register of Historic Places have been unsuccessful. Lunar landing sites (of both astronauts and man-made spacecraft, like lunar rovers) can’t be listed as a UNESCO World Heritage site, because the UN requires that listed sites be physically located in the country that is nominating them. Over 100 items have been discarded on the lunar surface by American astronauts, including moon boots, a gold replica of an olive branch, and a camera. Taken all together, they represent an irreplaceable snapshot in time.