After millennia of gazing up at our only natural satellite, humans made their first mark on the Moon on September 13, 1959. The Soviet spacecraft Luna 2 impacted the lunar surface at 7,400 mph (3.3 km per second), becoming the first human-made object to hit another celestial body.
Since then, nearly a hundred spacecraft have reached the Moon, many crash-landing (intentionally or otherwise). This equates to around half a million pounds (226,800 kg) of debris left behind by humans. For scientists at the University of Kansas, this amount of human interference is enough to suggest that a new geological epoch in the Moon’s history began in 1959 with the Luna 2 impact: the lunar Anthropocene. With dozens of missions planned to impact the Moon over the next few years, the lunar landscape is set to undergo more changes than ever before.
Perhaps most notably, NASA plans to land astronauts on the Moon as early as 2025 and begin constructing a lunar base in the 2030s. China has ambitions to build its own base even sooner. In the relatively near future, the Moon could also serve as a launch point for future missions further into space, especially to Mars.
Unlike on Earth, there are few biological or geomorphological systems on the Moon that would alter or erase the record of human activity. And there are numerous risks associated with the planned increase in human activity, such as rocket fuel contaminating the ice in the Moon's permanently shadowed areas. The Moon is rich in valuable resources like titanium, iron, silicon, and lithium that could eventually be mined, potentially resulting in changes to the Moon’s exosphere.
Space junk or space heritage?
- During the Apollo missions of the 1960s and 1970s, astronauts left a variety of objects on the lunar surface. There are nearly a hundred bags of human waste, numerous American flags, a family photo of Apollo 16 astronaut Charles Duke, the Fallen Astronaut memorial sculpture and plaque, and two golf balls struck by Alan Shepard during the Apollo 14 mission.
- A significant amount of technical equipment has also been left on the Moon, including descent stages of lunar modules, buggies, tools, retroreflectors, TV cameras, and more. Jettisoning this equipment allowed the Apollo astronauts to bring home hundreds of pounds of lunar rocks and soil for study on Earth.
- In 2019, the Israeli spacecraft Beresheet crashed into the Moon. Its payload contained several thousand tardigrades, micro-animals known to be able to withstand the effects of extreme conditions and ionizing radiation. Despite concerns about contaminating the lunar surface with biological material, it seems unlikely that they survived the shock pressure of the impact, according to a 2021 study from the Queen Mary University of London.
