Sputnik 1

From Wikipedia, the free encyclopedia

"Sputnik" redirects here. For other uses, see Sputnik (disambiguation).

Menu

0:00

The signals of Sputnik 1 continued for 22 days.

Sputnik 1 (Russian: "Спу́тник-1" Russian pronunciation: [ˈsputnʲɪk], "Satellite-1", ПС-1 (PS-1, i.e. "Простейший Спутник-1", or Elementary Satellite-1))^[2] was the first artificial Earth satellite. It was a 58 cm (23 in) diameter polished metal sphere, with four external radio antennas to broadcast radio pulses. The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957. It was visible all around the Earth and its radio pulses were detectable. The surprise success precipitated the American Sputnik crisis and triggered the Space Race, a part of the larger Cold War. The launch ushered in new political, military, technological, and scientific developments.^[3][4]

Sputnik itself provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave information about the ionosphere.

Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now at the Baikonur Cosmodrome). The satellite travelled at about 29,000 kilometres per hour (18,000 mph), taking 96.2 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz^[5] which were monitored by amateur radio operators throughout the world.^[6] The signals continued for 22 days until the transmitter batteries ran out on 26 October 1957.^[7] Sputnik 1 burned up on 4 January 1958, as it fell from orbit upon reentering Earth's atmosphere, after travelling about 70 million km (43.5 million miles) and spending 3 months in orbit.^[8]

Contents

• 1 Before the launch

• 1.1 Satellite construction project
• 1.2 Launch vehicle preparation and launch site selection
• 1.3 Observation complex

2 Design

3 Launch and mission

4 Reaction

• 4.1 Propaganda

5 Replicas

6 Impact

7 Backup units

8 See also

9 Notes

10 Bibliography

11 External links

• 11.1 Authentic recordings of the signal
• 11.2 History
• 11.3 Primary sources
• 11.4 Miscellaneous

Before the launch

Satellite construction project

The history of the Sputnik 1 project dates back to 17 December 1954, when Sergei Korolev addressed Dimitri Ustinov, the Minister of Defence Industries, proposing the development of an Earth-orbiting (artificial) satellite, forwarding a report by Mikhail Tikhonravov with an overview of similar projects abroad.^[9] Tikhonravov emphasized that an artificial satellite is an inevitable stage in the development of rocket equipment in 1951,^{[clarification needed]} after which "interplanetary communication" would become possible.^[10]

On 29 July 1955 the 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 (IGY).^[11] A week later, on 8 August the Presidium of the Central Committee of the CPSU approved the idea of creating an artificial satellite.^[12] On 30 August Vasily Ryabikov – the head of the State Commission on R-7 rocket test launches – 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.^[13]

This metal arming key is the last remaining piece of the first Sputnik satellite. It prevented contact between the batteries and the transmitter prior to launch. Currently on display at the Smithsonian National Air and Space Museum.

On 30 January 1956 the Council of Ministers approved practical work on an artificial Earth-orbiting satellite. This satellite, named "Object D", was planned to be completed in 1957–58; it would have a mass of 1,000 to 1,400 kg (2,200 to 3,090 lb) and would carry 200 to 300 kg (440 to 660 lb) of scientific instruments.^[14] The first test launch of "Object D" was scheduled for 1957.^[10] According to that decision, work on the satellite was to be divided between institutions as follows:^[15]

• USSR Academy of Sciences was responsible for the general scientific leadership and research instruments supply
• Ministry of Defence Industry and its main executor OKB-1 were assigned the task of creating the satellite as a special carrier for scientific research instruments
• Ministry of Radiotechnical Industry would develop the control system, radio/technical instruments and the telemetry system
• Ministry of Ship Building Industry would develop gyroscope devices
• Ministry of Machine Building would develop ground launching, refueling and transportation means
• Ministry of Defence was responsible for conducting launches

Thanks to Dimitrij Sergeevich Mordasov, the main engineer, by July 1956 the draft was completed and the scientific tasks to be carried out by the satellite were defined. It included measuring the density of the atmosphere, its ion composition, corpuscular solar radiation, magnetic fields, cosmic rays, etc. Data valuable in creating future satellites was also to be collected.^{[clarification needed]} A ground observational complex was to be developed, that would collect information transmitted by the satellite, observe the satellite's orbit, and transmit commands to the satellite. Such a complex should include up to 15 measurement stations. Because of the limited time frame, they should have means designed for rocket R-7 observations.^{[clarification needed]} Observations were planned for only 7 to 10 days and orbit calculations were expected to be not quite accurate.^[16]

Unfortunately, the complexity of the ambitious design and problems in following exact specifications meant that some parts of 'Object D', when delivered for assembly, simply did not fit with the others, causing very costly delays. By the end of 1956 it became clear that plans for 'Object D' were not to be fulfilled in time because of difficulties creating scientific instruments and the low specific impulse produced by the completed R-7 engines (304 sec instead of the planned 309 to 310 sec). Consequently the government re-scheduled the launch for April 1958.^[10] Object D would later fly as Sputnik 3.

Fearing the U.S. would launch a satellite before the USSR, OKB-1 suggested the creation and launch of a satellite in April–May 1957, before the IGY began in July 1957. The new satellite would be simple, light (100 kg or 220 lb), and easy to construct, forgoing the complex, heavy scientific equipment in favour of a simple radio transmitter. On 15 February 1957 the Council of Ministers of the USSR approved this, providing for launching the simplest version satellite, designated 'Object PS'.^[17] This version also facilitated the satellite to be tracked visually by Earth-based observers while in orbit, and transmit tracking signals to ground-based receiving stations.^[17] Launch of two satellites PS-1 and PS-2 with two R-7 rockets (8K71) was allowed, but only after one or two successful R-7 test launches.