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              Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI)
                                               PDS3 CERTIFIED

Instrument Description
PEPSSI is a hockey-puck-size (7.6cm diameter by 2.5 cm thick), time-of-flight (TOF) spectrometer that measures ions and electrons over a broad range of energies and pitch angles. Particle composition and energy spectra are measured for H to Fe from ~15 keV/nucleon to 1 MeV/nucleon and for electrons from 15 keV to 700 keV. The PEPSSI instrument traces its heritage back to the MESSENGER Energetic Particle Sensor (EPS) instrument. The instrument weighs 1.5 kg and uses a maximum of 1.4 W of power.

Scientific Objectives
Determine the escape rate of Pluto's atmosphere.

Measure the interaction of the solar wind with Pluto's ionosphere.

Determine the source and nature of energetic particles found near Pluto.

Note: Acquisition of Jupiter data was an add-on.

The PEPSSI data are housed at the PDS/PPI node

Useful Mission Documents

Also See Space Sci Rev (2008) 140: 315–38, DOI 10.1007/s11214-008-9436-y, Ralph McNutt, The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) on the New Horizons Mission.