Low-frequency electrostatic fluctuations in the ionospheric E region were detected by ador 3d allure massage chair instruments on the ROSE rockets.The phase velocity and dispersion of plasma waves in the ionospheric E region are determined by band-pass filtering and cross-correlating data of the electric-field fluctuations detected by the probes on the ROSE F4 rocket.The results were confirmed by a different method of analysis of the same data.The results show that the waves propagate in the Hall-current direction with a velocity somewhat below the ion sound speed obtained powell and mahoney bloody mary mix for ionospheric conditions during the flight.It is also found that the waves are dispersive, with the longest wavelengths propagating with the lowest velocity.