LAUSR

Measurements of light scattered by particles give insight into their physical properties (solid or liquid, size, shape, complex refractive index). We propose a novel instrument that provides in situ optical light-scattering measurements of aerosols in giant planet atmospheres, particularly in the ice giants Uranus and Neptune. Known as LONSCAPE (Light Optical Nephelometer Sizer and Counter for Aerosols for Planetary Environments), the instrument combines the particle counting technique of the LOAC balloon-borne aerosol counter with the well-known nephelometer technique to retrieve both the concentrations and phase functions of aerosols over 20 size classes in the 0.2–50 μm diameter size range. Such measurements allow us to distinguish between liquid, ice and solid (potentially carbonaceous) particles for all size classes, and thus to constrain the aerosols composition and their formation process. Given its low mass, size, and power requirements, LONSCAPE could become one of the key instruments selected to be part of the science payload of an atmospheric entry probe sent to the ice giants in the 2030s.