‘..on a 12 hour flight an airline passenger would experience 0.1 millisievert of radiation, or a rate of 0.2 millisieverts per day,..’

Or:

‘At the height of the Cold War, all international communications were either sent through undersea cables or bounced off the naturalionosphere. The United States Military was concerned that the Soviets might cut those cables, forcing the unpredictable ionosphere to be the only means of communication with overseas forces. So, a ring of 480,000,000 [2] copper dipole antennas (1.78cm long needles, 25.4μm [1961] / 17.8μm [1963] in diameter)[3][4] was placed in orbit to facilitate global radio communication. ‘

Thank you wikipedia