Sputnik I was the world's first artificial satellite that was launched by the USSR. They created history on October 4, 1957, when they launched the beach ball sized Earth-orbiting satellite. It was 22.8 inches in diameter and weighed 83.6 pounds. It took about 98 minutes to orbit the Earth on its elliptical path. This launch initially didn't create much furore in Moscow, but had a huge impact all over the world. The United States of America, that were until then considered leaders in space technology were jolted at the launch of Sputnik, and thus commenced the US-USSR space race.
The Sputnik seed was planted on May 27, 1954, when Sergei Korolev, head Soviet rocket engineer put forth a plan to develop an Earth-orbiting artificial satellite to Dmitry Ustinov, then Minister of Defense Industries. A report by Mikhail Tikhonravov suggested that similar projects were being carried out in several other countries. He also highlighted the essentialness of artificial satellites for the development of rocket equipment, which would also make interplanetary communication possible.
About a year and a half later, on January 30, 1956, the Council of Ministers of the USSR approved practical work on an artificial Earth-orbiting satellite. The time frame to develop this satellite called "Object D", was about two years. The planned size was between 2,200 to 3,090 lb and would ideally carry 440 to 660 lb of scientific equipment. The first test launch of "Object D" was scheduled for 1957. The development of this satellite was divided between different Russian organizations. Unfortunately, when some of the different parts of "Object D" came together, they did not fit. These costly delays, along with certain engine problems, made it clear that "Object D" would not be ready in time, and consequently the launch was re-scheduled.
The failure of the launch of "Object D" meant that the US could still launch a satellite before the USSR. Thus, scientists and engineers began to work on a lighter, simpler satellite called 'Object PS', to be propelled by an R-7 rocket. This satellite could be visually tracked by Earth-based observers while in orbit, and transmit tracking signals to ground-based receiving stations. On September 22, 1957, a modified R-7 rocket, named Sputnik Rocket, along with the satellite PS-1, arrived at the proving ground and preparations for the launch began.
M.S. Khomyakov was the chief constructor of Sputnik 1. The satellite was a sphere with a diameter of 23 inches. It was assembled from two hemispheres which were hermetically sealed using o-rings and connected using 36 bolts. The satellite had two antennas. The power supply had a mass of 110 lb, and was shaped like an octahedral nut with the radio transmitter in its hole. It carried three silver-zinc batteries, which powered the radio transmitter and the temperature regulation system. The satellite contained a one-watt, 7.7 lb radio inside, that transmitted on two frequencies, 20.005 and 40.002 MHz. The temperature was regulated by a system made up of a fan, a dual thermal switch, and a control thermal switch. Sputnik 1 was filled with dry nitrogen which was pressurized to 1.3 atm. It was protected by a cone-shaped payload fairing while attached to the rocket.
The Sputnik Rocket was launched during the International Geophysical Year on October 4, 1957, at 19:28:34 UTC, from Site No.1 at the 5th Tyuratam range. The control system of this Rocket was programmed to provide an orbit of perigee height 223 km (139 mi), apogee height 1,450 km (900 mi), and orbital period 101.5 min. The satellite traveled at 29,000 km/hr, taking 96.2 minutes to complete an orbit, and emitted radio signals which were monitored by amateur radio operators all over the world. The signals continued for 22 days until the transmitter batteries ran out on October 26, 1957. It also helped to identify the upper atmospheric layer's density through measuring the satellite's orbital changes. It also provided data on radio-signal distribution in the ionosphere. It burned up upon re-entry on January 4, 1958.
With the launch of Sputnik, the USSR became pioneers in space technology. They had many more firsts, including sending the first living being (a dog named Laika) into space, and later the first human (Yuri Gagarin) into outer space.