During the Apollo missions between 1969 and 1972, NASA astronauts planted six American flags on the Moon’s surface. Unlike Earth, the Moon has no atmosphere to filter ultraviolet (UV) radiation from the Sun. This exposes materials directly to intense solar radiation and extreme temperature swings.
Ultraviolet radiation gradually breaks down chemical bonds in pigments and fabrics. Over decades, the red and blue dyes in the nylon flags would likely have degraded significantly. Without atmospheric protection, fading would occur much faster than on Earth, leaving the fabric bleached and colorless.
In addition to UV exposure, the Moon experiences temperature extremes ranging from about +127°C during lunar day to −173°C at night. These repeated thermal cycles weaken materials over time. Some flags may also have been knocked down by rocket exhaust when lunar modules lifted off.
Orbital images suggest at least some flags are still standing, though their current color cannot be directly observed in detail. Scientists widely agree that they have likely faded substantially, possibly appearing mostly white today.
The fading flags illustrate how unforgiving the lunar environment is. Even simple fabric undergoes dramatic transformation under constant radiation and temperature stress.
