  We calculate the flux of neutral solar wind observed on the lunar surface at
the terminator due to solar wind protons penetrating exospheric dust grains
with (1) radii greater than 0.1 microns and (2) radii greater than 0.01
microns. For grains with radii larger than 0.1 microns, the ratio of the
neutral solar wind flux produced by exospheric dust to the incident ionized
solar wind flux is estimated to be about 10^-4-10^-3 for solar wind speeds in
excess of 800 km/s, but much lower (less than 10^-5) at average to slow solar
wind speeds. However, when the smaller grain sizes are considered, this ratio
is estimated to be greater than 10^-5 at all speeds, and at speeds in excess of
700 km/s reaches about 10^-3. These neutral solar wind fluxes are easily
measurable with current low energy neutral atom instrumentation. Observations
of neutral solar wind from the surface of the Moon would provide independent
information on the distribution of very small dust grains in the lunar
exosphere that would complement and constrain optical measurements at
ultraviolet and visible wavelengths.
