  Electrostatic analyzers of different designs have been used since the
earliest days of the space age, beginning with the very earliest solar wind
measurements made by Mariner 2 en route to Venus in 1962. The Parker Solar
Probe (PSP) mission, NASA's first dedicated mission to study the innermost
reaches of the heliosphere, makes its thermal plasma measurements using a suite
of instruments called the Solar Wind Electrons, Alphas, and Protons (SWEAP)
investigation. SWEAP's electron Parker Solar Probe Analyzer (SPAN-E)
instruments are a pair of top-hat electrostatic analyzers on PSP that are
capable of measuring the electron distribution function in the solar wind from
2 eV to 30 keV. For the first time, in-situ measurements of thermal electrons
provided by SPAN-E will help reveal the heating and acceleration mechanisms
driving the evolution of the solar wind at the points of acceleration and
heating, closer than ever before to the Sun. This paper details the design of
the SPAN-E sensors and their operation, data formats, and measurement caveats
from Parker Solar Probe's first two close encounters with the Sun.
