PEP - Particle Environment Package
PEP (Particle Environment Package) is a particle spectrometer to measure neutral and charged particles in the Jupiter system. The PEP-Instrument onboard JUICE consists of two units with a total of six different sensors.
- PEP-Lo (JEI, NIM, JNA, and JDC)
- PEP-Hi (JoEE, JENI)

Scientific Goals
Based on the JUICE science matrix PEP will tackle the following research topics:
- Ganymede: Which interaction processses exist between the rotating Jovian magnetosphere and the complex Ganymede system?
- Callisto: Characterization of the moon Callisto as a relict of the evolution history of the Jupiter system.
- Europa and Io: Study of active regions on Europa and Io; remote sensing of neutral gas tori;
- Remote sensing of the irregular satellites and the ring system.
- Jupiter’s magnetosphere: Study and influence of internal and external plasma sources in the Jupiter system; studiy of acceleration mechanisms; characterization of the „magnetodisc“.
In detail::
- Determination of temporarily highly resolved three-dimensional velocity distributions in the Jovian magnetosphere, and especially in the vicinity of the moons Europa, Ganymede and Callisto
- Determination of the Ion-composition in the Jovian magnetosphere.
- Characterisation of the interaction processes between the magnetospheric plasma and released particles from the surface of the moons.
- Characterisation of processes relevant to dexcribe the Jovian aurora and the Ganymede aurora.
- Highly resolved pitch angle distributions of ions and electrons in the Jupiter system to investigate acceleration mechanisms.
- Global Investigation of charged exchange processes between „cold“ neutral gas and „hot“ ions (ENA-Imaging).
- Study of „weathering“-processes on the surfaces of the moons through sputtering and release of neutral and charged particles.
- Characterisation of the moon's exospheric composition.