Magnetic Anomaly Navigation

Magnetic field intensity (left) and topography (right) of the Moon centered over the giant 2200 km diameter South Pole-Aitken impact basin. Significant quantities of metallic iron from the projectile were deposited on the northern rim of the basin that became magnetized in the presence of a magnetic field, forming several large magnetic anomalies. Low values of both the magnetic field strength and topography are plotted in blue colors, which grade to red for high values. Source: Wieczorek, M. A., B. P. Weiss, and S. T. Stewart.