A swarm of N SAR sensors,both transmitting and receiving,in a geostationary orbit,might provide all-day-all-weather imaging within a continental region,using direct downloading for real time data exploitation.The coherent combinations of all the echoes would improve the signal-to-noise ratio by a factor of N2,leading to metric resolution,20-40 minutes minimum observation time,multi-polarimetric and interferometric imaging.Fast evolving events like landslides,floods,soil moisture changes,volcanic activity,co-seismic motions,infrastructure deformations and columnar water-vapour maps could be monitored continuously from space for the first time.The observed area could have a footprint from hundreds to a thousand kilometres wide,according to the resolution,settable using electronic steering,anytime,anywhere within a continent,and a flexible access that can span from the south to the north hemisphere.