Humans have intentionally, and by accident contaminated the moon’s surface beyond imagination.
What we did to the moon can be described best: We came. We saw. We littered.
Did you know that there are more than 175,788 kilograms (more than 387,546.2 pounds) of artificial, manmade objects on the moon’s surface?
Some of these objects were intentionally crashed on the surface, some of them crashed by accident, while others landed on the moon’s surface during the various lunar missions sent by the United States and the Soviet Union.
And while we made sure to leave a lot of trash behind, Apollo astronauts who set foot on the moon and the Soviet Luna Missions brought back to Earth a total of 380 kilograms (838 lb) of Moon rock.
47 objects were crashed and/or sent to land on the moon by the United States, with a total weight of 109,670.8 kilograms.
21 objects belong to the Soviet Union totaling a weight of 60,383.2 kilograms. The Societ Union successfully landed 8 of its missions, while they left behind 13 objects that crashed.
China has three artificial objects on the moon’s surface, the Chang’e 1, Change’ 3 and Yutu, with a total weight of 3,200 kilograms. The Change’1 was intentionally crashed into the moon. The Yutu Rover ceased functioning in March 2015, which its lender, the Change’ 3 continues operational to this day.
In less than a month the Chang’e 4 Mission is set to touch down on the moon’s far side which will make it the fourth object China has on the moon. Currently, Ranger 4, Lunar Orbiter 1, Lunar Orbiter 2 and Lunar Orbiter 3 are all located on the moon’s far side.
Japan has four objects on the Moon’s surface, with a total weight of 2,192 kilograms.
The European Space Agency intentionally crashed its SMART-1 probe into the Moon’s surface, ending its mission on September 3, 2006. The SMART-1 probe has a weight of 307 kilograms.
The above totals 76 large, manmade objects on the moon, with a weight of little over 175,000 kilograms.
The best (or should I say worst) part is that of all the above-mentioned objects only the retroreflectors for the lunar laser ranging experiments left there by the Apollo 11, 14, and 15 astronauts and by the Lunokhod 1 and Lunokhod 2 missions are still in use.
Here is a detailed catalog by NASA on what objects have ended up on the moon’s surface.