PEP (Particle Environment Package) will study the interaction between space and Jupiter’s icy moons.
The instrument with its six sensors will investigate how neutral and charged particles, such as ions, electrons and atoms,
behave in the magnetosphere and the electrical fields contained in the Jupiter system.

  The NIM instrument is a highly sensitive mass spectrometer for neutral atmospheric gas and ionospheric ions specifically 
  developed for the tenuous gases of planetary exospheres. It is a time-of-flight mass spectrometer using an ion mirror for 
  performance optimization. It will be used to measure the chemical composition of the regular atmosphere produced by sublimation, 
  energetic particle bombardment, and photon interaction with the surface of the icy Jovian moons. Its measurements include volatile species, 
  contributions from non-ice material on the surface, and the measurement of the isotope composition of major species. In addition, 
  NIM will also measure the ion composition of the ionospheres by direct ion measurement.