  Persephone is a NASA concept mission study that addresses key questions
raised by New Horizons' encounters with Kuiper Belt objects (KBOs), with
arguably the most important being "Does Pluto have a subsurface ocean?". More
broadly, Persephone would answer four significant science questions: (1) What
are the internal structures of Pluto and Charon? (2) How have the surfaces and
atmospheres in the Pluto system evolved? (3) How has the KBO population
evolved? (4) What are the particles and magnetic field environments of the
Kuiper Belt? To answer these questions, Persephone has a comprehensive payload,
and would both orbit within the Pluto system and encounter other KBOs. The
nominal mission is 30.7 years long, with launch in 2031 on a Space Launch
System (SLS) Block 2 rocket with a Centaur kick stage, followed by a 27.6 year
cruise powered by existing radioisotope electric propulsion (REP) and a Jupiter
gravity assist to reach Pluto in 2058. En route to Pluto, Persephone would have
one 50- to 100-km-class KBO encounter before starting a 3.1 Earth-year orbital
campaign of the Pluto system. The mission also includes the potential for an
8-year extended mission, which would enable the exploration of another KBO in
the 100- to 150-km-size class. The mission payload includes 11 instruments:
Panchromatic and Color High-Resolution Imager; Low-Light Camera; Ultra-Violet
Spectrometer; Near-Infrared (IR) Spectrometer; Thermal IR Camera; Radio
Frequency Spectrometer; Mass Spectrometer; Altimeter; Sounding Radar;
Magnetometer; and Plasma Spectrometer. The nominal cost of this mission is
$3.0B, making it a large strategic science mission.
