The study of ionospheric and auroral phenomena by the European Space Research Organization continues with the successful launching on 1 October of ESRO-1B, the second satellite in the ESRO-1 project, from the Western Test Range in California. The satellite carries eight experiments, including two from the Radio and Space Research Station, Slough, and two from the Mullard Space Research Laboratory, University College, London; their main purpose is to investigate the fine structure of aurorae and to correlate studies on auroral particles, auroral luminosity, ionospheric composition and heating effects.