Lunar loo: Did Apollo astronauts' 96 bags of poop and urine seed the Moon with life?

The way our human ancestors left behind paraphernalia like their tools for us to learn about them, our successors will likely inherit a ton of trash on this planet from modern humans. Granted, we won’t be making the best of impressions. But that’s just who we are, we leave garbage everywhere we go — including the Moon.

Believe it or not, scattered across the lunar terrain are not just American flags, science equipment, and astronaut boot prints, but also... bags of poop. Yes, you read that right! During the six Apollo missions that landed on the moon between 1969 and 1972, astronauts left behind a combined total of 96 bags filled with their urine, faeces and other human waste.

Why, you ask? The decision was purely “practical”!

The poo bags paradox

Space missions have strict weight limits, and every pound counted when it came to safely blasting off from the lunar surface. So instead of lugging their waste back to Earth, astronauts left it behind in favour of bringing home priceless lunar rock samples and scientific data. In fact, alongside human waste, they also left equipment like cameras, boots, and even golf balls from Alan Shepard’s famous moon swing in 1971.

The thrash left behind by Apollo astronauts on the Moon is frozen in vacuum-packed bags, and the question of whether it will survive is scientifically intriguing. The Moon’s environment is extremely hostile to life as we know it. As it has no atmosphere, there’s no protection against harmful radiation from the sun, and the temperatures fluctuate drastically from +120°C to -133°C throughout the day.

These conditions make it highly unlikely that any Earth-based microbes could survive, let alone thrive, on the lunar surface. But some scientists disagree!

Microbes’ journey to the Moon

Despite these harsh conditions, some scientists believe the bacteria in the poop may have survived. Some forms of bacteria are known to be extremely resilient and can potentially endure harsh environments.

While it's a very slim possibility, “the introduction of terrestrial substances onto the moon or other celestial bodies could, permanently, jeopardize the existence of possible indigenous lifeforms,” says Hugo Lopez, a researcher at the French National Centre for Scientific Research, in a 2020 study titled, “The Protection of Cultural Heritage Sites on the Moon: The Poo Bags Paradox”.

Another theory is that, in the vacuum-packed bags, with no oxygen, moisture, or atmospheric pressure, the bacterial organisms might have entered a state of dormancy. In this state, they could theoretically be "revived" if reintroduced to more favourable conditions, such as Earth's environment or inside a lab for study.

A long-standing question

The survival of bacteria in these bags could provide important insights into the long-standing question ‘how microorganisms endure in space?”, which is crucial for understanding the potential of life on other planets and ensuring safety of humans on long-term space missions. However, it's also possible that the high radiation levels on the moon have killed off any remaining life forms in the waste, as radiation can damage DNA over time.

For now, Mark Lupisella, a manager at NASA’s Goddard Space Flight Center, has suggested a robotic mission to collect samples from the waste bags left at an Apollo landing site. The goal would be to study whether the microbes inside the bags have survived or spread in the lunar environment, a discovery that could provide essential insights for future space exploration.

Until then, whether the poop survives on the Moon is still an open question, but it offers an exciting opportunity for scientists to study the limits of microbial life and the conditions for survival beyond Earth!

Though it’s an amusing thought that human waste is among our first interplanetary "artefacts," these remnants are part of an enduring legacy of exploration — and leaving trash everywhere.