Pioneer Venus Sounder Probe Particle Size Spectrometer

The Pioneer Venus Sounder Probe Particle Size Spectrometer measured the particle size and number density in the atmosphere of Venus from 66 km to the surface. This instrument performs particle size measurements over a 0.5 to 500-μm size range using a combination of shadowgraph imaging and light scattering techniques. Size resolution is approximately ±10 percent of size with 100-400-m vertical spacial resolution. The instrument features a laser-fed optical system incorporating a complex beam-splitting multipath imaging optical system.