The Active Spacecraft POtential Control instrument uses indium ions to limit the positive spacecraft potentials in order to improve the performance and measurements from the other instruments.


The Energetic Particle Detector suite consists of the Energetic Ion Spectrometer (EIS) and Fly's Eye Energetic Particle Sensor (FEEPS) to measure the energy-angle distribution and composition of ion and energetic electrons.


The Fields investigation measures the magnetic and electric fields via five instruments: The Fluxgate Magnetometer (FGM), Axial Double Probes (ADP), Spin-Plane Double Probes (SDP), Search Coil Magnetometer (SCM), and Electron Drive Instrument (EDI).


The Fast Plasma Instrument (FPI) measures the velocity-space distribution of electrons and ion from 10 eV to 30 KeV.


The Hot Plasma Composition Analyzer (HPCA) measures the composition and velocity-space distribution of ions from 1 eV to 40 keV.


Spacecraft ephemerides are provided as additional non-observational data products to enable to analysis of MMS data.