"The factor which had caused the militant five percent to relax a while from fomenting discord was the satellites."

Satellite
Creative Commons Attribution Share AlikeSatellite - Credit: Poppy
Wyndham shows some prescience here. At the time of publication (1951), no man-made satellite had yet been launched into space. The first satellite to be successfully put into orbit was the Soviet Sputnik 1 in 1957.