An artist's illustration of the fallen Apollo 11 flagRuby Aitken

Editor's Note: This article is part of a series reflecting on the Apollo 11 mission, 50 years later.

About 4.5 billion years ago, according to the most popular theory of the moon’s formation, a mysterious rocky world the size of Mars slammed into Earth. From the fiery impact, shards swirled and fused into a new, airless world, itself bombarded with rocky objects. In the absence of the smoothing touch of weather and tectonic activity, every dent remained. And then, one day, among craters both microscopic and miles-wide, two guys came along and stepped on the surface, carving new hollows with their boots.

Buzz Aldrin, seeing the moon from the surface for the first time, described it as “magnificent desolation.”

It was not so desolate when they departed. The Apollo 11 astronauts discarded gadgets, tools, and the clothesline contraption that moved boxes of lunar samples, one by one, from the surface into the module. They left behind commemorative objects—that resplendent American flag, mission patches and medals honoring fallen astronauts and cosmonauts, a coin-size silicon disk bearing goodwill messages from the world leaders of planet Earth. And they dumped things that weren’t really advertised to the public, for understandable reasons, such as defecation-collection devices. (Some scientists, curious to examine how gut microbes fare in low gravity, even proposed going back for these.)

Fifty years later, of everything that remains at the cosmic campsite, the American flag has had the worst time of it.

The flag is no longer standing. In fact, it’s been flat on the ground since the moment Aldrin and Neil Armstrong lifted off. As the Eagle module ignited its engines and rose, spewing exhaust around, Aldrin caught a glimpse of the flag falling from his window.

The flag, made of nylon, was an off-the-shelf purchase. Unlike Earth, the moon lacks an atmosphere capable of blocking out the worst of the sun’s rays. It wouldn’t have taken long for the ultraviolet light to eat away at the dye and bleach the flag white. “Have you ever seen burnt newspaper from a fireplace? All the color is gone and everything,” says Dennis LaCarrubba, who worked at the New Jersey–based company that manufactured the flag. “That’s probably what the flag would look like now.”

The photographic evidence for this came decades later, thanks to NASA’s Lunar Reconnaissance Orbiter, a spacecraft that still circles the moon today. The spacecraft’s camera photographed several Apollo landing sites. The NASA astronauts who flew to the moon in the late 1960s and early 1970s always brought American flags with them. In photos of later Apollo missions, you can see, amid all the pockmarked gray terrain, a little white smudge and, right next to it, a slightly bigger, black smudge—a flag, faded from the glow of the sun, and its shadow.

Scientists long thought that the sun exposure would cause the fabric to disintegrate, reducing the little monuments of American achievement to dinky poles surrounded by fibers. But the orbiter photos suggest that the fabric has withstood the conditions.

The photos also provide some defense against people who believe the moon landing was faked. Julie Stopar, a scientist at the Lunar and Planetary Institute and a member of the lunar orbiter’s imaging team, carries postcards of the landing sites in case she runs into someone with doubts, including her own friends and family. “They’ll ask me jokingly—and in some cases, not so jokingly—‘Are you sure we really landed on the moon?’ And it’s like, ‘Yes, I am sure. I’ve seen it, and we have pictures of it,’” Stopar says. “And then I’ll show them the pictures and then they’re like, ‘Oh, okay, I guess that’s pretty convincing.’”

The resolution of the orbiter’s cameras isn’t strong enough to make out the Apollo astronauts’ boot prints, but some may have been blasted out of existence when the exhaust of the Eagle’s engines slammed into the regolith. Subsequent Apollo missions captured footage of the turbulent experience of liftoff. “You can see a severe blowing occurring; you can see flags flapping in the wind like it’s a hurricane; you can see dust lifting off the surface everywhere,” says Phil Metzger, a planetary scientist at the University of Central Florida.

The tracks outside of the blast zone were likely undisturbed, though, and most anything made with metals—the lower half of the Eagle, a seismometer, commemorative plaques, assorted tools—has probably fared well on the moon. The module’s gold foil, which provided warmth for its passengers, has probably faded and splintered. And one of the experiments is still going.

Armstrong and Aldrin placed on the surface a boxy array of mirrors designed to reflect incoming light back to its source without significantly scattering. Several times a month, Tom Murphy, a physics professor at the University of California at San Diego, instructs a telescope in southern New Mexico to beam a laser at the instrument. The light sprints home in two and a half seconds. “The photons that we make in our laser go out, touch these reflectors, and come back to us and report,” says Murphy, who uses the measurements to study the fundamentals of gravity.

The mirrors still provide good data, but they don’t work like they used to. Murphy suspects that they’re covered in dust, which degrades their reflectivity, especially during a full moon, when particles absorb the direct sunlight, creating thermal distortions. During an eclipse, when the near side of the moon is in darkness, the reflectors return to their usual performance.

No one has ever returned to the site of Apollo 11. No one has been on the moon’s surface at all since 1972, but national governments, commercial companies, and nonprofits alike are hoping to make it. In preparation for a potential moon rush, NASA has created guidelines for future commercial spacecraft that include no-fly zones and warnings to keep a distance.

The Apollo 11 site is a historical landmark, and it should be treated as such, says Michelle Hanlon, a co-founder of For All Moonkind, an organization of lawyers who specialize in space law. Hanlon believes that the Apollo spots deserve the same protections as heritage sites on Earth. “If you go to the pyramids, you assume they’re protected,” she says. “If you think about the moon, humanity’s greatest technological achievement, you assume that’s protected, too.” Hanlon recently worked with members of Congress to write legislation that would enforce preservation rules for historic lunar sites; the Senate approved the bill this week.

If human beings someday inhabit the moon, they might consider doing more than designating the Apollo 11 landing site a landmark. They could cover the area with geodesic domes, as a protective measure against contamination, and let people come a little closer. Visitors would pop over to an Apollo 11 gift shop to browse rocket-ship keychains and chalky astronaut ice cream.

When they peer through the gossamer bubble, inspecting the provincial exploration efforts of earlier generations, those visitors might look closely at the ground near the lunar module. Armstrong and Aldrin took only the top part of the capsule back into space with them, and the lower half—the one that famously nearly ran out of fuel seconds before Armstrong touched down—might have acted as a shield for the boot prints closest by.

This presents a tantalizing possibility: The first human step on another world might be in pristine condition. It might be caked in a thin coating of dust, but it could still be there, recognizable to future space travelers, should any ever arrive.

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