Magnetic fields are everywhere in our solar system. They originate from the Sun, planets, and moons, and are carried throughout interplanetary space by solar wind. This is precisely why magnetometers—devices used to measure magnetic fields—are flown on almost all missions in space to benefit the Earth, Planetary, and Heliophysics science communities, and ultimately enrich knowledge for all humankind. These instruments can remotely probe the interior of a planetary body to provide insight into its internal composition, structure, dynamics, and even evolution based on the magnetic history frozen into the body’s crustal rock layers. Magnetometers can even discover hidden oceans within our solar system and help determine their salinity, thereby providing insight into the potential habitability of these icy worlds.