Small instrument—wide range
The magnetometer is astonishingly small compared to its performance and capacity. The size of a tennis ball, the sensor is placed in a cylinder and with a pineapple-like surface. The grooves on the surface hold coils that generate a magnetic field similar to what you want to measure. The spacecraft itself is taller than a human and weighs just under two tonnes without fuel and just under three with fuel, so the weight of the magnetometer, which is about 2 kg, is not much in comparison. But it is efficient and reliable, developed and built manually at DTU with a focus on every little detail.
We know absolutely nothing about Psyche's magnetic field—whether it is large or small; whether it is a single large field or a scattering of smaller fields. The magnetometer must be prepared for all eventualities.
DTU’s magnetometer is unique in being able to measure the size and direction of magnetic fields with extreme precision. The strength of magnetic fields is usually measured in tesla. For very weak magnetic fields, measurements are stated in nanotesla (nano = 10-9). The Earth’s magnetic field measured in Denmark is approximately 54,000 nanotesla.
The magnetometer from DTU is capable of detecting extremely weak magnetic fields measuring down to just 0.025 nanotesla as well as extremely strong fields measuring up to 80,000 nanotesla. This means that the weakest magnetic field measurable by the instrument is six million times less powerful than the strongest field it can measure. In other words: The instrument can detect magnetic fields ranging from the weak fields of solar wind to the stronger magnetic fields of large planets.