  The Solar System contains a population of dust and small particles
originating from asteroids, comets, and other bodies. These particles have been
studied using a number of techniques ranging from in-situ satellite detectors
to analysis of lunar microcraters to ground-based observations of zodiacal
light. In this paper, we describe an approach for using the LISA Pathfinder
(LPF) mission as an instrument to detect and characterize the dynamics of dust
particles in the vicinity of Earth-Sun L1. Launching in late 2015, LPF is a
dedicated technology demonstrator mission that will validate several key
technologies for a future space-based gravitational-wave observatory. The
primary science instrument aboard LPF is a precision accelerometer which we
show will be capable of sensing discrete momentum impulses as small as $4\times
10^{-8}\,\textrm{N}\cdot\textrm{s}$. We then estimate the rate of such impulses
resulting from impacts of micrometeoroids based on standard models of the
micrometeoroid environment in the inner solar system. We find that LPF may
detect dozens to hundreds of individual events corresponding to impacts of
particles with masses $> 10^{-9}\,$g during LPF's roughly six-month science
operations phase in a $5\times 10^5\,\textrm{km}$ by $8\times
10^5\,\textrm{km}$ Lissajous orbit around L1. In addition, we estimate the
ability of LPF to characterize individual impacts by measuring quantities such
as total momentum transferred, direction of impact, and location of impact on
the spacecraft. Information on flux and direction provided by LPF may provide
insight as to the nature and origin of the individual impact and help constrain
models of the interplanetary dust complex in general. Additionally, this direct
in-situ measurement of micrometeoroid impacts will be valuable to designers of
future spacecraft targeting the environment around L1.
