Six instruments comprise the Particles and Fields package: Solar Energetic Particle (SEP); Solar Wind Ion Analyzer (SWIA); Solar Wind Electron Analyzer (SWEA); SupraThermal and Thermal Ion Composition (STATIC); Langmuir Probe and Waves (LPW); and Magnetometer (MAG). There is also an Imaging UltraViolet Spectrograph (IUVS) and a Neutral Gas and Ion Mass Spectrometer (NGIMS).
Two of these instruments, SWIA and SEP, are mounted on the body of the spacecraft. The extreme ultraviolet monitor component of LPW is also body-mounted and faces the sun. Two instruments, SWEA and LPW, are mounted on booms extending from the spacecraft. The two magnetometer sensors are mounted at the ends of the craft’s solar panels, in order to get them as far away from the core structure of the spacecraft as possible. Three instruments, NGIMS, STATIC, and IUVS, are mounted on the articulated payload platform, which extends on a boom and continually rotates as the spacecraft orbits so that the instruments can continually view the planet.