Aeolus is a satellite set to monitor global winds, at all levels throughout the troposphere and stratosphere (the lower 30km or so where most of the weather driving activity occurs), in near real time. This will bring about a huge improvement in numerical weather modelling, greatly help improve climate models and improve understanding of the dynamics and direction of various key environmental processes (eg weathering). The key instrument for this is the Aladin Doppler wind lidar which will continuously generate wind profiles as it sweeps around the planet. It is set to launch on a Vega rocket (fast ascent!) from Kourou, French Guiana, at 2220BST this evening. Live coverage here from about 2200BST.