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Abstract

Data of the Pioneer 11 meteoroid experiment are re-evaluated. A probabilistic model of the dust detector is constructed with no assumption on the flux of particles, using built-in redundancy of the instrument only. The analysis of redundant data strongly suggests that the instrument had suffered a failure at launch that disabled a significant part of its impact sensors. This failure reduced the total sensitive area of the detector, and the fluxes derived earlier assuming the instrument was in good health underestimated the true fluxes. We apply our model to re-derive the true particle fluxes, taking now the reduction of the initial sensor number into account. We implement a kind of in-flight calibration of a dust detector in natural meteoroid environment. We end up with higher true fluxes and wider confidence intervals that represent the best knowledge of the instrument's in-flight characteristics.