Description NASA Counting Craters on the Moon. Using the Lunar Reconnaissance Orbiter's Laser Altimeter, NASA scientists have been counting craters to create the first-ever, comprehensive catalog of large craters on the Moon. Here, individual craters larger than 20 kilometers in diameter "light up" using LOLA elevation data. By studying these data, scientists have discovered that, in the Moon's early history, the proportion of large impact craters to small impact craters was higher, indicating that proportionally more larger craters were formed then. This provides clues to the chaotic early days of the inner solar system, including Earth's own history.