sentences:  Many investigations of the magnetosphere and auroral regions have been made using rockets and satellites.McIlwain discovered from a rocket flight in 1960 that the energy spectrum of auroral electrons exhibited a peak that was thought then to be too sharp to be produced by a random process and which suggested, therefore, that an ordered process was responsible.It was reported in 1977 that satellites had detected the signature of double layers as electrostatic shocks in the magnetosphere.