One of the key areas of study of NASA's Earth Science enterprise is the role played by clouds in climate change. The duration of conventional research aircraft is limited so that long-term measurements required to validate satellite observations are not practical. Small uninhabited aerial vehicles (UAVs) and tethered balloons, however, are now capable of making sustained, long-term (30 hr) measurements, so that data sets can be collected that provide much better statistical comparisons with results from satellite retrieval algorithms. In Phase I we produced system designs and performed laboratory tests to investigate the feasibility of manufacturing a small, lightweight (< 1.5 Kg) cloud particle imager, called a Micro-CPI, for application on the Aerosonde Piccolo, the most-widely used small UAV for weather research. In Phase II, Micro-CPIs will be fabricated and flight-tested on the Aerosonde UAV at the Aerosonde facility located at the NASA Wallops Island Research Facility. The Aerosonde Corporation has agreed to commit technical consulting and materials to support the Phase II effort. The Micro-CPI will measure the size distributions of both water and ice particles. The extremely high resolution images (3-micron) of ice crystals can be used to determine their shape and light-scattering properties, information that is crucial for reliable validation of satellite retrievals used to monitor global climate change.