On October 4, 1957, for the first time in human history, the artificial satellite (Sputnik) was launched into a low Earth orbit.
The Sputnik-1 is a sealed ball-shaped container. It's made of an ultra-strength aluminum-magnesium alloy 2 millimeters thick. The upper hemisphere is covered by a thermal protective shield 1 millimeter thick. Its polished surface absorbs self- and solar radiation.
The Sputnik's body consists of two hemispheres connected by 36 bolts. It is filled with nitrogen at internal pressure of 1.3 atmospheres. The Sputnik's operation and research data collection are provided by the minimum equipment. Its paired antennae broadcast uniformly radio ultra-short and short wave signals.
Automatic system controls inside temperature and provides nitrogen circulation and heat dissipation from the board equipment to the lower hemisphere if temperature exceeds +23°C. Whenever temperature falls below +20...+23°C, the fan is automatically turned off by the thermal relay system.
The onboard equipment is powered by silver-zinc batteries. The self-contained power supply system is activated after a nosecone fairing has separated. It is designed to operate for 2-3 weeks.
The onboard radio, model d200, consisted of radio valve (model 2P19B 'Palma' (Palm) series), is DF of radio waves in the ionosphere. The upper part of the transmitter includes a relay and temperature and pressure sensors. The body's vibrations are softened by shock-absorbing plates.
The launch vehicle, indexed as 8K71PS No. 1 M1-PS, is a modified intercontinental ballistic missile R-7 rocket. The primary stage consists of 4 identical combustion chambers located around the combustion chamber of the stage 2. Engine ignition of both stages occurs simultaneously at a rocket launch. The fuel is kerosene, while the oxidizer is liquid oxygen.
The rocket-Sputnik carrier was launched at 22:28:34 (MSK, UTC +3) on October 4th, 1957 from the training ground of the USSR Ministry of Defense (today called the Baikonur launch base). It reached the orbital velocity (the 1st cosmic velocity). 295 seconds after the launch the rocket's central block reached the Earth's elliptical orbit. 314,5 seconds later a nosecone fairing was dropped and the Sputnik separated.
On January 4th, 1958 the Sputnik 1 reentered the Earth's atmosphere and burned up in its dense layers. The Soviet's Sputnik became a major milestone of discovering space. Obtained data pertaining the upper layers of atmosphere, equipment's operation, and radio signals propagation in the ionosphere were extremely significant for the humankind.