— Ch. 1 · Origins And Development —
Sputnik 1.
~8 min read · Ch. 1 of 7
On the 17th of December 1954, chief Soviet rocket scientist Sergei Korolev proposed a developmental plan for an artificial satellite to the Minister of the Defense Industry, Dimitri Ustinov. Korolev forwarded a report by Mikhail Tikhonravov that outlined similar projects abroad. Tikhonravov emphasized that launching an orbital satellite was an inevitable stage in rocket technology development. On the 29th of July 1955, U.S. President Dwight D. Eisenhower announced through his press secretary that the United States would launch an artificial satellite during the International Geophysical Year. Four days later, Leonid Sedov, a leading Soviet physicist, announced that they too would launch an artificial satellite. On the 8th of August, the Politburo of the Communist Party of the Soviet Union approved the proposal to create an artificial satellite. On the 30th of August, Vasily Ryabikov held a meeting where Korolev presented calculation data for a spaceflight trajectory to the Moon. They decided to develop a three-stage version of the R-7 rocket for satellite launches. On the 30th of January 1956, the Council of Ministers approved practical work on an artificial Earth-orbiting satellite named Object D. This satellite was planned to be completed in 1957, 58 and would have a mass of 84 kilograms. It would carry 3 kilograms of scientific instruments. The first test launch of Object D was scheduled for 1957. Work on the satellite was divided among several institutions including the USSR Academy of Sciences and OKB-1. Preliminary design work was completed in July 1956. By the end of 1956, it became clear that Object D could not be launched in time due to difficulties creating scientific instruments. Consequently, the government rescheduled the launch for April 1958. Fearing the U.S. would launch a satellite before the USSR, OKB-1 suggested creating a simpler satellite designated Object PS. On the 15th of February 1957, the Council of Ministers of the USSR approved this simple satellite.
Technical Architecture
Sputnik 1 was a polished metal sphere with a diameter of 58 centimeters. It was assembled from two hemispheres that were hermetically sealed with O-rings and connected by 36 bolts. The satellite had a mass of 83.6 kilograms. The hemispheres were 2 millimeters thick and covered with a highly polished 1-millimeter-thick heat shield made of an aluminium, magnesium, titanium alloy. The satellite carried four external radio antennas designed by Mikhail V. Krayushkin. Each antenna consisted of two whip-like parts that were 2.4 to 2.9 meters long. The power supply weighed 3.5 kilograms and took the shape of an octagonal nut with the radio transmitter inside its hole. Three silver-zinc batteries developed at the All-Union Research Institute of Power Sources powered the system. Two batteries powered the radio transmitter while one powered the temperature regulation system. The batteries had an expected lifetime of two weeks but operated for 22 days. A one-watt radio transmitting unit worked on frequencies of 20.005 and 40.002 MHz. Signals on the first frequency were transmitted in 0.3-second pulses near 3 Hz. Analysis of the radio signals gathered information about electron density in the ionosphere. Temperature and pressure were encoded in the duration of radio beeps. Sputnik 1 was filled with dry nitrogen pressurized to 130 kPa. The satellite had a barometric switch activated if internal pressure fell below 130 kPa.