  The ESA meteoroid model predicts impacts of meteoroids in the mass range
between $10^{-18}$ to $10^0$ g on spacecraft surfaces. It covers heliocentric
distances from 0.3 to 20 AU. Measurements of the dust detector on board the
highly successful joint ESA/NASA mission Ulysses have shown, that the flux of
meteoroids with masses between $10^{-15}$ and $10^{-12}$ g is, at least in the
outer Solar System, dominated by interstellar dust grains that traverse the
Solar System as it travels through the local interstellar cloud. We present a
simple semi-analytic interstellar dust model that can easily be included in the
ESA meteoroid model, together with a more precise determination of the flux
direction of the interstellar dust stream. The model is based on the assumption
that interstellar dust dynamics have two effects: solar gravitation and
radiation pressure determines the spatial distribution, and Lorentz-interaction
of the charged particles creates a temporal variation.
