WIVERN, an Earth Explorer, is short for wind velocity radar nephoscope – to provide the first measurements of wind within clouds and precipitation systems. It promises to deliver profiles of rain, snow and ice water. Carrying a dual-polarisation, conically scanning, 94 GHz Doppler radar with an 800 km swath, the mission aims to improve forecasts of hazardous weather and provide new insights into severe storms, and contribute to the climate record of cloud and precipitation profiling.