Plasma experiment for planetary exploration (PEPE)

The Plasma Experiment for Planetary Exploration (PEPE) flown on Deep Space 1 combines an ion mass spectrometer and an electron spectrometer in a single, low-resource instrument. Among its novel features PEPE incorporates an electrostatically swept field-of-view and a linear electric field time-of-flight mass spectrometer. A significant amount of effort went into developing six novel technologies that helped reduce instrument mass to 5.5 kg and average power to 9.6 W. PEPE's performance was demonstrated successfully by extensive measurements made in the solar wind and during the DS1 encounter with Comet 19P/Borrelly in September 2001.