We use a combination of space-borne instruments to study the unprecedented stratospheric plume after the Hunga Tonga eruption of 15 January 2022. The plume was formed of two initial clouds at 30 and 28 km mostly composed of submicronic sulphate particles without ashes, washed-out within the first hours. The large amount of water vapour injected led to a fast conversion of SO 2 to sulphates and induced a descent of the plume over the first three weeks by radiative cooling. While SO 2 returned to background levels by the end of January, the sulphate plume persisted until June, mainly confined between 20 • N and 35 • S due to the zonal symmetry of the summer stratospheric circulation at 24-25 km. As sulphate particles grew through hydration and coagulation, they sediment and separate from the ascending moisture entrained in the Brewer-Dobson circulation. Sulphate aerosol optical depths derived from the IASI infared sounder show that the aerosol plume was not simply diluted and dispersed passively but rather organized in concentrated patches. Winds from the space-borne Doppler lidar ALADIN/AEOLUS suggest that those structures, generated by shear-induced instabilities, are associated with vorticity anomalies. They likely enhance the duration and impacts of the plume.