For the past half-century, the Moon has been the destination of some of humankind’s most monumental and challenging expeditions.
As the Moon becomes more accessible to both national space programs and private enterprise, it is important that we protect lunar artifacts for both their historic and scientific value.
It's challenging to say, but the trash on the moon likely weighs upward of 400,000 lbs. (181,000 kilograms) on Earth.
Much of this moon litter was left by NASA astronauts who landed on the lunar surface between 1969 and 1972 during the Apollo program.
The other rubbish comes from crewless missions from space-exploring agencies, including those from the United States, Russia, Japan, India and Europe.
Many of the older pieces are lunar probes that were sent to the moon to learn about it, such as whether spaceships could land on its surface.
In the 1960s, some scientists thought that the moon might have a quicksand-like exterior because so many space rocks had pummeled and pulverized it over the years.
These robotic probes, which stayed on the moon after their missions ended, showed that this idea was wrong, and that human-made gear could land on the moon's surface.