The Apollo program successfully landed humans on the Moon six times between 1969 and 1972. During each mission, after establishing a safe landing, astronauts deployed a United States flag assembly near the Lunar Module. This symbolic gesture became an enduring image of humanity’s first steps on another celestial body, raising questions about the fate of these artifacts over the decades.
The Status of the Flags
The six successful Apollo missions that landed on the Moon—Apollo 11, 12, 14, 15, 16, and 17—each left a flag on the lunar surface. The question of whether these flags remain upright is answered with a qualified yes for the majority of the sites. Evidence suggests that five of the six flags are still standing on their aluminum poles.
The exception is the first flag, planted by the Apollo 11 crew at Tranquility Base. Astronaut Buzz Aldrin reported seeing the flag fall over from the blast of the Lunar Module’s ascent engine during liftoff. Subsequent missions placed the flag assemblies further away from the landing craft, a successful measure for preservation.
The remaining five flag assemblies, consisting of the flagpole and horizontal crossbar, appear to have survived the departure of their respective crews. These flags were not designed to be retrieved, remaining permanent historical artifacts on the Moon. While the structures remain, their physical condition after more than five decades in the harsh lunar environment is another matter entirely.
How Scientists Confirmed the Flags’ Presence
Confirming the status of these flags from Earth is impossible. The Lunar Reconnaissance Orbiter (LRO), a robotic NASA probe mapping the Moon since 2009, provided the answer. The LRO’s Narrow Angle Camera (NAC) is equipped with cameras capable of resolving features on the scale of meters, detecting objects roughly half a meter (20 inches) in size.
The LRO did not photograph the flags themselves, which are too small and thin to be clearly resolved by the orbiting camera. Instead, scientists analyzed a series of images taken at different times of the lunar day, focusing on the shadows cast by the objects. The long, slender shadows stretching across the lunar dust confirmed the presence of an upright, pole-like structure at the landing sites of Apollo 12, 16, and 17.
The shadows cast by the flags from the Apollo 14 and 15 missions are less definitive but still suggest their presence. Crucially, LRO imagery of the Apollo 11 site shows no shadow where the first flag was planted, corroborating Aldrin’s account that it was knocked over. Tracking the movement of these shadows over time provides proof that the poles remain fixed in the lunar regolith.
The Effects of the Lunar Environment on the Flags
The nylon fabric of the flags was purchased as standard, off-the-shelf items, never intended to withstand the Moon’s extreme conditions. Without an atmospheric filter, the surface is constantly bombarded by intense, unfiltered solar ultraviolet (UV) radiation. This high-energy radiation is highly destructive to organic materials like nylon, causing photodegradation.
This continuous UV exposure would have broken down the chemical bonds in the fabric’s dyes almost immediately, meaning the red, white, and blue colors have almost certainly bleached out. Experts conclude that the flags are now likely a uniform, stark white. The nylon material itself would have also become extremely brittle, potentially disintegrating in places.
The flags have also endured cycles of extreme thermal shock every lunar day. Temperatures swing from scorching highs of about 100°C (212°F) during the two-week day to frigid lows of approximately -150°C (-238°F) during the two-week night. This massive temperature variation, combined with abrasive, electrostatically charged lunar dust, ensures that while the aluminum poles remain standing, the fabric is now a fragile, colorless relic.