In the mid sixties, it became possible to use rockets to carry out in-situ
measurements of the ionosphere. The nature of the measurements depended
on the instruments flown.
Radio. By measuring radio signals transmitted from the ground
to receivers on the rocket, it was possible to study the distribution of ionisation,
especially in the lower portions of the ionosphere where conventional
ionosondes were of limited use.
Magnetometers. Electric currents in the E layer were also measured
using magnetometers carried aloft by rockets launched from Sardinia, Woomera
(Australia) and Thumba (India). The structure of Sporadic-E layers (thin,
dense layers caused by metal ions of meteoric origin), the equatorial
electojet and the distribution of currents during ionospheric storms were the
main subjects of this research.
Ultra-violet lamps By measuring the response of the atmosphere to
ultra-violet, it was possible to make estimates of the distribution of atomic
oxygen in the lower ionosphere. Atomic oxygen is important to the complex
chemistry in these regions, but was almost impossible to measure before the
advent of this technique.
Spectrometers. Rockets were, and still are, used to study
the intensity and and energy spectra of the energetic particles that
produce the aurora borealis or Northern Lights. These experiments, carried
aloft by Skylark, Petrel and Fulmar rockets have added greatly to our
knowledge of this spectacular phenomenon.