  The Solar Probe Cup (SPC) is a Faraday Cup instrument onboard NASA's Parker
Solar Probe (PSP) spacecraft designed to make rapid measurements of thermal
coronal and solar wind plasma. The spacecraft is in a heliocentric orbit that
takes it closer to the Sun than any previous spacecraft, allowing measurements
to be made where the coronal and solar wind plasma is being heated and
accelerated. The SPC instrument was designed to be pointed directly at the Sun
at all times, allowing the solar wind (which is flowing primarily radially away
from the Sun) to be measured throughout the orbit. The instrument is capable of
measuring solar wind ions with an energy/charge between 100 V and 6000 V
(protons with speeds from $139-1072~km~s^{-1})$. It also measures electrons
with an energy between 100 V and 1500 V. SPC has been designed to have a wide
dynamic range that is capable of measuring protons and alpha particles at the
closest perihelion (9.86 solar radii from the center of the Sun) and out to
0.25 AU. Initial observations from the first orbit of PSP indicate that the
instrument is functioning well.
