The expected frequency of collisions of small meteorites with cars and aircraft

The cumulative distribution N(d) of diameters of Earth-Crossing Asteroids ( ECAs) derived by Poveda et al. (1998, submitted) is used to estimate the fr equency of collisions of meteoroids with cars and with aircraft. The expect ed frequency of collisions of a car with a meteorite larger than 10 cm in d iameter turns out to be one impact every 16 years. This frequency is consis tent with the known incidence of such events (Lewis, 1996). The expected fr equency of collisions of a cruising airplane with a meteorite larger than 1 cm in diameter turns out to be one impact every 30 years. Such an impactor hitting an airplane at a velocity of several hundreds of meters per second could cause a serious accident. (C) 1999 Elsevier Science Ltd. All rights reserved.