The 60th anniversary of the launch of Sputnik 1, Earth’s first artificial satellite, is Wednesday, October 4. The Soviet Union heralded the launch as a national triumph, and the space race between the USSR and the US began. Sputnik 1 was fairly basic — a sphere with four antennas that transmitted a 1-W signals on 20.005 and 40.002 MHz, putting it within the range of nearly any radio amateur, and WWV halted its nighttime 20-MHz transmissions to avoid interfering with the satellite’s signal.
The Russian-language Radio magazine earlier had published articles on the proposed telemetry system and intended downlink frequencies. An English-language version subsequently later appeared in QST. The US also had revealed its intention to launch a satellite during the International Geophysical Year 1957 — but the USSR was the only country to do so that year; Explorer 1 was not launched until January 31, 1958.
A 58-centimeter diameter polished metal sphere, Sputnik 1 could be seen from Earth, orbiting the planet about once every 96 minutes. It had no stabilization system. Two aluminum casings bolted together with a seal created an airtight housing for the two transmitters plus temperature and pressure sensors.
Scientists studying it gained information about such things as the density of the upper atmosphere, deduced from orbital drag. The propagation of its signals also helped to better understand the ionosphere. — Thanks to Jim Linton, VK3PC