  Meteoroids originating from the local interstellar medium, traverse the solar
system. This has been proven by in situ measurements by interplanetary
spacecraft as well as highly sensitive radar measurements. Early attempts to
detect interstellar meteoroids using the instruments on board the Pioneer 8 and
9 spacecraft failed. More sensitive detectors on board the joint ESA/NASA
mission Ulysses as well as on board the NASA spacecraft Galileo, however,
unambiguously detected meteoroids of interstellar origin. This discovery has
started efforts to compare the results from the in situ measurements with
highly sophisticated models of interstellar dust properties derived from
astronomical absorption and extinction measurements. It was found that, at
least locally, is more mass locked up in meteoroids than expected from the
astronomical measurements. So far the in situ measurements only allow to derive
composition information indirectly via the meteoroid's dynamics.
