The inner rim of Gruithuisen K (35.4°N, 317.3°E) in LROC NAC frame M111877130L. Image width is 510 meters, or 1673 feet, north is up, and sunlight is from the lower right.

Impact craters affect the entire surface of the Moon, from micron-sized pits to multi-ringed impact basins. Lunar craters also have a wide array of morphologies. Generally, the size and the morphology of a crater depends on the size and velocity of the impacting bolide. Lunar scientists have used crater size and form to group lunar craters into three basic categories: simple craters, complex craters, and multi-ringed basins. Simple craters are circular, bowl-shaped, and usually less than 10-15 km in diameter. Complex craters are usually larger than 10-20 km in diameter and have a well-defined central peak. Complex craters also often have a rim with one or more terraces. The central peak is brought up from great depths beneath the crater as the ground elastically rebounds after the shock and pressure of the bolide impact. Multi-ringed basins are remnants of the largest impacts on the lunar surface and usually have more than one rim (such as the 1100 km diameter Imbrium Basin).

NASA's Goddard Space Flight Center built and manages the mission for the Exploration Systems Mission Directorate at NASA Headquarters in Washington. The Lunar Reconnaissance Orbiter Camera was designed to acquire data for landing site certification and to conduct polar illumination studies and global mapping. Operated by Arizona State University, LROC consists of a pair of narrow-angle cameras (NAC) and a single wide-angle camera (WAC). The mission is expected to return over 70 terabytes of image data.