Ice cell convection on Pluto, New Horizons image. Close-up of ice blocks (water and nitrogen) being formed and reformed in Pluto's Sputnik Planum region. This area of Pluto's icy surface is being constantly renewed by a process called convection that replaces older surface ices with fresher material. These churning ice 'cells' were imaged using the Multispectral Visible Imaging Camera (MVIC). The area shown here is about 400 kilometres across. The image data was acquired during the flyby of Pluto by the New Horizons spacecraft on 14 July 2015.