Launch vehicle preparation and launch site selection

he two-stage R-7 rocket was initially designed as an ICBM by OKB-1. The decision to build it was made by the CPSU Central Committee and the Council of Ministers of the USSR on 20 May 1954.^[14] A special reconnaissance commission selected Tyuratam as a place 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.^[15] Actual work on the construction of the site began on 20 July by military building units. On 14 June 1956 Sergei Korolev decided to adapt the R-7 rocket to the 'Object D',^[16] that would later be replaced by the much lighter 'Object PS'.

The first launch of an R-7 rocket (8K71 No.5L) occurred on 15 May 1957. The flight was controlled until the 98th second, but a fire in a strap-on rocket led to an unintended crash 400 km from the site.^[17] Three attempts to launch the second rocket (8K71 No.6) were made on 10-11 June, which failed due to a mistake made during the rocket's assembly.^[18] The unsuccessful launch of the third R-7 rocket (8K71 No.7) took place on 12 July.^[17] During the flight the rocket began to rotate about its longitudinal axis and its engines were automatically turned off. The packet of stages was destroyed 32.9 seconds into the flight. The stages fell 7 km (4.3 mi) from the site and exploded.^[19]

The launch of the fourth rocket (8K71 No.8), on 21 August at 15:25 Moscow Time,^[17] was successful. Its head part separated, reached the defined region, entered the atmosphere, and was destroyed at a height of 10 km (6.2 mi) due to thermodynamic overload after traveling 6,000 km. On 27 August TASS the USSR issued a statement on the launch of a long-distance multistage ICBM. The launch of the fifth R-7 rocket (8K71 No.9), on 7 September^[17] was also successful, but the head part was also destroyed in the atmosphere,^[19] and hence needed a long redesign to completely fit its military purpose. The rocket, however, was already suitable for scientific satellite launches and this "time-out" of the rocket's military exploitation was used to launch the PS-1 and PS-2 satellites.^[20]

On 22 September a modified R-7 rocket, named Sputnik Rocket (Russian: ракета-носитель Спутник) and indexed as 8K71PS, with the satellite PS-1, arrived at the proving ground and preparations for the launch began.^[21] As the R-7 was designed to carry the much heavier Object D, its adaptation to PS-1 reduced its initial mass from 280 to 272.83 short tons (250 to 250 metric tons) and its mass at launch was 267 short tons (242 metric tons); its length with PS-1 was 29.167 metres (95 ft 8.3 in) and the thrust was 3.90 MN (880,000 lb_f)