A film demonstrating the activities at NASA's ground-based ionospheric stations, where scientists take vertical incidence soundings of the ionosphere. Commencing with footage of the NASA Wallops rocket research range, the film demonstrates: analysing ionograms, which show frequency-flight relationships and therefore general parameters of the ionosphere; sounding rocket launches; ground stations marked on a globe; the UK-1 aerial NASA/UK ionospheric satellite; an electron density profile graph; continuous wave [CW] propogation techniques - CW signal generator, oscillator in proportional oven; diagram to illustrate how the refractive index at the rocket can be derived; setting-up of experimental radiations for the pre-launch checkout; low-frequency antenna, high-frequency antenna, receiving equipment; CW-derived international prototype payload - checking of instrumentation, Langmuir probe with typical electron density profile graph, payload encapsulation, second stage with shroud antennae; ground station monito