Representative chemical, structural, and morphological analyses of the large (>1-μm diameter) solid particles from three impaction collection surfaces have been performed. These collections sampled the stratosphere at approximately 17--19 km in altitude during 1976, 1981, and 1984. For these sampling periods the statospheric solid-particle number densities have been determined to be 0.089, 0.16, and 1.7 particles m-3 of air, respectively, for particles of >1-μm diameter. This rise in the solid-particle number density for the stratosphere over the collection period is likely due to the influx of solid rocket exhaust and rocket and satellite debris into the atmosphere in increasingly larger amounts with time. Some of this material is shed from spacecraft during ascent through the atmosphere, but the majority is probably provided during the descent of material from Earth's growing belt of debris in low-Earth orbit. ¿ American Geophysical Union 1989