The recent recovery of the Hubble Space Telescope (HST) Solar-Array-1 and the European Retrievable Carrier (EURECA) spacecraft offers an opportunity to widen our database on the low Earth particle environment. This paper describes investigations into impacts observed on the array surfaces after retrieval, and into calibration impact tests carried out using a plasma drag accelerator at the Fachgebiet Raumfahrttechnik, TU Munchen. We have concentrated on examining 'microimpacts' (less than 500 mu m in diameter). These small impacts form a consistent data set, as they are almost all craters in the cover glass of the solar cells. The size distribution and different morphologies of the impacts were established during optical and scanning electron microscope examinations. The results from a series of shots using the plasma drag accelerator are combined with experiments performed during the Apollo programme to give a scaling law for particle parameters and impact crater dimensions. This can then be used to convert the observed crater size distribution on the solar arrays to flux distributions, which can then be compared with results from models and from other satellites. (C) 1997 COSPAR. Published by Elsevier Science Ltd.