Estimation of the impactors radial velocity from the impact rates. Left panel: impact rate as a function of radial distance. The black points show fluxes recorded when the spacecraft is moving toward the Sun, the red points when moving outward from the Sun. Each point is computed by averaging the impact rate data on 50 distance intervals linearly spaced between 0.5 and 1 AU. Error bars show one standard deviation error on the computation of the mean. Middle panel: radial component of the dust velocity, V_r, dust, computed from Eq. (4). Error bars are computed by propagating errors on the impact rates shown on the left panel. Right panel: histogram of the obtained values of V_r, dust.