  Studying lunar dust is vital to the exploration of the Moon and other airless
planetary bodies. The Ultraviolet and Visible Spectrometer (UVS) on board the
Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft conducted a
series of Almost Limb activities to look for dust near the dawn terminator
region. During these activities the instrument stared at a fixed point in the
zodiacal background off the Moon's limb while the spacecraft moved in
retrograde orbit from the sunlit to the unlit side of the Moon. The spectra
obtained from these activities probe altitudes within a few kilometers of the
Moon's surface, a region whose dust populations were not well constrained by
previous remote-sensing observations from orbiting spacecraft. Filtering these
spectra to remove a varying instrumental signal enables constraints to be
placed on potential signals from a dust atmosphere. These filtered spectra are
compared with those predicted for dust atmospheres with various exponential
scale heights and particle size distributions to yield upper limits on the dust
number density for these potential populations. For a differential size
distribution proportional to $s^{-3}$ (where $s$ is the particle size) and a
scale height of 1 km, we obtain an upper limit on the number density of dust
particles at the Moon's surface of 142 $m^{-3}$.
