A rendering of Blue Origin’s Blue Moon lander that will return astronauts to the Moon as part of NASA’s Artemis program. (Source: Blue Origin website)Future crewed missions to the Moon could unintentionally erase some of the oldest chemical evidence linked to the origins of life on Earth, according to a new study that raises concerns about contamination from spacecraft landings.As Nasa prepares to expand its Artemis programme with more astronaut missions and a long-term lunar base near the Moon’s south pole, researchers say exhaust gases from lunar landers could pollute ancient ice deposits that have remained largely undisturbed for billions of years.The study focuses on permanently shadowed craters near the Moon’s poles, where temperatures are cold enough for ice to survive indefinitely. Scientists believe this ice contains material delivered by asteroids and comets during the early history of the solar system, including prebiotic organic molecules — the building blocks that may have contributed to the emergence of life on Earth.Also Read | How many astronauts should live on the moon? New study points to ideal numberUnlike Earth, where geological activity and erosion have erased much of the planet’s earliest chemical history, the Moon has remained relatively unchanged. As a result, these frozen deposits could preserve an ancient record of molecules from the time when life first emerged.Using computer simulations, researchers found that methane, a major component of rocket exhaust from planned lunar landers, could spread rapidly across the Moon after a landing. Because the Moon has virtually no atmosphere, methane molecules would travel in ballistic “hops” across the surface instead of dispersing through the air.Also Read | Why Nasa’s next alien-hunting super telescope will rely entirely on robots for fixesThe simulations suggest methane released during landings near the South Pole could reach the Moon’s north pole in less than two lunar days. Within about a lunar week, researchers estimate that more than half of the methane would become trapped in permanently shadowed polar regions, including the same icy craters scientists hope to study.