The moon's going to get crowded. We should protect our heritage on it while we still can

In 1959, the Luna 2 probe from the Soviet Union became the very first human-made object to reach our closest celestial neighbor. In the decades since, we have been leaving footprints—both literally and figuratively—all over the moon. Today, there are over 100 metric tons of human-made material resting on the moon's surface—everything from advanced cameras and sensors to literal human waste. But that's nothing compared to what's to come. NASA predicts the next decade will see over 100 new lunar missions, equaling or exceeding all the missions previously flown, which brings up a pressing question about all the stuff that's already there—how do we protect that history?