The Psyche Magnetic Cleanliness Testing Campaign

The metal-rich asteroid (16) Psyche is hypothesized to have formed from the core of an early planetesimal. In October 2023, NASA launched the Psyche spacecraft to observe the asteroid. The spacecraft carries a multispectral imager, a gamma ray and a neutron spectrometer, and a magnetometer. The key requirement of the Magnetometry Investigation is to establish whether (16) Psyche has a remanent dipole moment. However, the spacecraft itself also has a magnetic field. Therefore, prior to launch, the magnetic cleanliness of the spacecraft was vigorously assessed. This included characterizing flight-system components and modeling the spacecraft fields. Solar arrays were characterized using both testing and analysis. This campaign concluded with a novel system-level test approach to determine the integrated flight-system magnetic field at the location of the flight magnetometers. Here we describe the solar array and system-level testing methods, analysis, and modeling. The results demonstrated that the Psyche flight-system was sufficiently magnetically clean to enable the magnetometer to meet its level-1 requirement.