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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Sputnik 1 | 3/8 | https://en.wikipedia.org/wiki/Sputnik_1 | reference | science, encyclopedia | 2026-05-05T13:23:17.580301+00:00 | kb-cron |
The R-7 rocket was initially designed as an intercontinental ballistic missile (ICBM) by OKB-1. The decision to build it was made by the Central Committee of the Communist Party of the Soviet Union and the Council of Ministers of the USSR on 20 May 1954. The rocket was the most powerful in the world; it was designed with excess thrust since they were unsure how heavy the hydrogen bomb payload would be. The R-7 was also known by its GRAU (later GURVO, the Russian abbreviation for "Chief Directorate of the Rocket Forces") designation 8K71. At the time, the R-7 was known to NATO sources as the T-3 or M-104, and Type A. Several modifications were made to the R-7 rocket to adapt it to 'Object D', including upgrades to the main engines, the removal of a 300 kg (660 lb) radio package on the booster, and a new payload fairing that made the booster almost four metres (14 feet) shorter than its ICBM version. Object D would later be launched as Sputnik 3 after the much lighter 'Object PS' (Sputnik 1) was launched first. The trajectory of the launch vehicle and the satellite were initially calculated using arithmometers and six-digit trigonometric tables. More complex calculations were carried out on a newly-installed computer at the Academy of Sciences. A special reconnaissance commission selected Tyuratam for the construction of a rocket proving ground, the 5th Tyuratam range, usually referred to as "NIIP-5", or "GIK-5" in the post-Soviet time. The selection was approved on 12 February 1955 by the Council of Ministers of the USSR, but the site would not be completed until 1958. Actual work on the construction of the site began on 20 July by military building units. The first launch of an R-7 rocket (8K71 No.5L) occurred on 15 May 1957. A fire began in the Blok D strap-on almost immediately at liftoff, but the booster continued flying until 98 seconds after launch when the strap-on broke away and the vehicle crashed 400 km (250 mi) downrange. Three attempts to launch the second rocket (8K71 No.6) were made on 10–11 June, but an assembly defect prevented launch. The unsuccessful launch of the third R-7 rocket (8K71 No.7) took place on 12 July. An electrical short caused the vernier engines to put the missile into an uncontrolled roll which resulted in all of the strap-ons separating 33 seconds into the launch. The R-7 crashed about 7 km (4.3 mi) from the pad. The launch of the fourth rocket (8K71 No.8), on 21 August at 15:25 Moscow Time, was successful. The rocket's core boosted the dummy warhead to the target altitude and velocity, reentered the atmosphere, and broke apart at a height of 10 km (6.2 mi) after travelling 6,000 km (3,700 mi). On 27 August, the TASS issued a statement on the successful launch of a long-distance multistage ICBM. The launch of the fifth R-7 rocket (8K71 No.9), on 7 September, was also successful, but the dummy was also destroyed on atmospheric re-entry, and hence needed a redesign to completely fulfill its military purpose. The rocket, however, was deemed suitable for satellite launches, and Korolev was able to convince the State Commission to allow the use of the next R-7 to launch PS-1, allowing the delay in the rocket's military exploitation to launch the PS-1 and PS-2 satellites. On 22 September a modified R-7 rocket, named Sputnik and indexed as 8K71PS, arrived at the proving ground and preparations for the launch of PS-1 began. Compared to the military R-7 test vehicles, the mass of 8K71PS was reduced from 280 to 272 tonnes (617,000 to 600,000 lb), its length with PS-1 was 29.167 metres (95 ft 8.3 in) and the thrust at liftoff was 3.90 MN (880,000 lbf).
=== Observation complex === PS-1 was not designed to be controlled; it could only be observed. Initial data at the launch site would be collected at six separate observatories and telegraphed to NII-4. Located back in Moscow (at Bolshevo), NII-4 was a scientific research arm of the Ministry of Defence that was dedicated to missile development. The six observatories were clustered around the launch site, with the closest situated 1 km (0.62 mi) from the launch pad. A second, nationwide observation complex was established to track the satellite after its separation from the rocket. Called the Command-Measurement Complex, it consisted of the coordination center in NII-4 and seven distant stations situated along the line of the satellite's ground track. These tracking stations were located at Tyuratam, Sary-Shagan, Yeniseysk, Klyuchi, Yelizovo, Makat in Guryev Oblast, and Ishkup in Krasnoyarsk Krai. Stations were equipped with radar, optical instruments, and communications systems. Data from stations were transmitted by telegraphs into NII-4 where ballistics specialists calculated orbital parameters. The observatories used a trajectory measurement system called "Tral", developed by OKB MEI (Moscow Energy Institute), by which they received and monitored data from transponders mounted on the R-7 rocket's core stage. The data were useful even after the satellite's separation from the second stage of the rocket; Sputnik's location was calculated from data on the location of the second stage, which followed Sputnik at a known distance. Tracking of the booster during launch had to be accomplished through purely passive means, such as visual coverage and radar detection. R-7 test launches demonstrated that the tracking cameras were only good up to an altitude of 200 km (120 mi), but radar could track it for almost 500 km (310 mi).
Outside the Soviet Union, the satellite was tracked by amateur radio operators in many countries. The booster rocket was located and tracked by the British using the Lovell Telescope at the Jodrell Bank Observatory, the only telescope in the world able to do so by radar. Canada's Newbrook Observatory was the first facility in North America to photograph Sputnik 1.
== Design ==
Sputnik 1 was designed to meet a set of guidelines and objectives such as: