First artificial satellite orbits the Earth

On October 4, 1957, the USSR successfully launched the world's first satellite aboard a converted R-7 intercontinental ballistic missile.


The access gantries enclosing the rocket and the satellite on the launch pad were lowered at around T-15 minutes. (252) Shortly before launch, Korolev along with top launch officials Leonid Voskresensky, A. I. Nosov and Evgeny Ostashev descended into the launch control bunker to monitor the blastoff. (70) A senior technician from NII-229 test center Anatoly Korneev, who served as an operator of the main control console in the bunker, pressed a "pusk" (liftoff) button. (546)

The launch vehicle with the PS-1 satellite lifted off into the night sky over Kazakhstan on October 4, 1957, at 22:28:34 Moscow Time. (250) It was already October 5 in Tyuratam.

As the rocket disappeared in the night sky, Korolev, Tikhonravov, Bushuev, Reshetnev and Ivanovsky rushed to the cars for a ride to the assembly building at Site 2, where they hoped to "hear" the signals from the first satellite. (250)

Soon after the powered flight of the rocket was over, operators of the Tral system received a signal confirming the engine cutoff. After comparing the time of the signal with the count of a mechanical sports chronometer, they happily concluded that the engine shutdown had taken place within the time period required to deliver a satellite into orbit. After a short pause, Lieutenant Borisov, manning a radio in a cottage at the IP-1 tracking station, heard from the satellite. The Space Age has began! The signal lasted for about two minutes until the satellite went out of range. Exhausted members of the test personnel, who crowded in the cottage, celebrated the success. (51)

Before the satellite completed its first orbit, the official TASS news agency announced the launch to the world. (51)

The flight controllers intentionally left the Tral telemetry system onboard the core stage of the rocket active as it had began orbiting the Earth and the Tral's signal was then picked up during the second orbit of the mission.

Post-launch analysis


Ground track of the first satellite

In the meantime, specialists started analyzing telemetry gathered during the launch. The data revealed that the rocket had lifted off normally, deviating from the nominal trajectory no more than 0.3 degrees. In the meantime, the rotation of the steering thrusters did not exceed 3.6 degrees.

However, as it turned out, the main engine on the Block G strap-on booster of the rocket was late developing its intended thrust. As a result, 6.5 seconds after the launch, the rocket started to pitch, deviating around one degree from the nominal trajectory eight seconds after the liftoff. In the effort to correct the increasing pitch angle, steering engines No. 2 and 4 on the core stage rotated as much as eight degrees; similar engines on strap-on boosters of Block V and D rotated as much as 17-18 degrees, while tail air rudders rotated 10 degrees.

Only a split second remained before the flight control system would terminate the flight of the underpowered rocket. Fortunately, the engine finally reached normal performance and the rocket fully returned to its nominal trajectory between 18 and 20 seconds after the liftoff.

In the meantime, at T+16 seconds, the SOB system, regulating the consumption of the propellant onboard failed, leading to the excessive consumption of the kerosene fuel. During the almost entire powered flight, the combustion chamber pressure remained throttled up some four percent from standard.

The middle portion of the powered flight went with less drama: from 60th to 70th second of the mission, the deviation from the nominal pitch angle was reaching 0.75 degrees, while deviation in the course was about one degree. At the 100th second of the flight, the bank angle increased to one degree from nominal. Maximum rotation angles for steering engines of the core stage remained within 3-3.5 degrees, for thrusters on strap-on boosters these indicators remained within 6 or 8 degrees and for air rudders -- from 2 to 3 degrees.

The separation between first and second stages took place after 116.38 seconds in flight. Just 0.33 seconds later, a command to shut down (first stage) main engines, known as VOD, was issued. Telemetry showed the reduction of thrust of the engines (of the first stage) within accepted parameters. In the aftermath of the staging, the attitude of the core stage, which continued firing, did not change above 0.5 degrees. Steering thrusters had no need to rotate more than 6-7 degrees on yaw and course channels, which was also within nominal parameters.

The second stage flew normally with pitch and bank parameters deviating 0.3 degrees from nominal and the course parameter was off by 0.6 degrees. Steering engines No. 1 and 3 rotated up to four degrees and engines No. 2 and 4 up to six degrees. (84)

As the second stage continued to fire, telemetry registered oscillations of steering engines with the frequency of 6.5 Hz and reaching 7.5 Hz by the 280th second in flight. The amplitude of the oscillation reached 2.3 degrees. The oscillations stopped after T+280 seconds. The phenomenon was linked to the flexing of the rocket body.

At T+285 seconds, a new wave of oscillations shook the engines, this time with a frequency of 1.5-1.6 Hz and an amplitude of two degrees. This time, it was believed to be a result of oscillations of the liquid propellant inside the rocket. (84)

As a result of the SOB system failure, the propulsion system run out of fuel just one second before a nominal command from the programming timer to cut off the engines could be sent at T+296.4 seconds. (84) Instead, at 295.4 seconds after the liftoff (51), the engine was shut down by the AKT (Avariyny Contact Turbiny) sensor, which detected the increased spin of the fuel pump turbine, as it was no longer burdened by the flow of fuel. At that moment, 375 kilograms of liquid oxygen oxidizer still remained onboard the rocket.

At the moment of the engine shutdown, the rocket was flying with a speed of 7,780 meters per second, at an altitude of 228.6 kilometers above the Earth's surface, with an angle of 0 degrees 21 (24) minutes toward the local horizon. (84)

The second stage of the rocket and the satellite entered the 228 by 947-kilometer orbit, with an inclination 65.1 degrees toward the Equator, which took 96.2 minutes to complete. (52) (Another source, quoted orbital parameters as being 223 by 950 kilometers. 84) In any case, the premature engine shutdown left the satellite in an orbit between 80 and 90 kilometers below nominal.


The PS-1 satellite separated 314.5 seconds after the launch, or 19.9 seconds after the engine shutdown. (A built-in nominal delay for the separation was 18-20 seconds). (84)

A signal for the deployment of the angular reflector mounted on the body of the core stage was sent at 325.44 seconds. The device allowed more accurate tracking of the rocket's orbital parameters. (84)


Summary of launch events:

Time Event
T+0 Liftoff
T+16 seconds SOB system failure
T+116.38 seconds Four Stage I boosters separate from Stage II
T+295.4 seconds Stage II engine cutoff (actual)
T+296.4 seconds Stage II engine cutoff (nominal)
T+314.5 seconds Satellite separates from Stage II of the rocket in orbit
T+325.44 seconds Deployment of angular reflector on Stage II


End of mission

The satellite transmitted temperature data for 22 days before its power sources went dead. (217) Moscow Radio announced that on October 26, 1957. (174)

The core stage of the R-7 rocket made 882 orbits and reentered on December 2, 1957. The satellite made 1,440 orbits and then burned up on the reentry into the Earth atmosphere on January 4, 1958, after 92 days in space. (84)




Written and illustrated by Anatoly Zak

All rights reserved

Last update: October 4, 2021

insider content


Sputnik animation

Sputnik enters orbit, opening Space Age. Click to play: Streaming QuikTime. Copyright © 2007 Anatoly Zak


The first artificial satellite of the Earth blasts off from Site 1 in Tyuratam (Baikonur) at 22:28 Moscow Time on October 4, 1957. Credit: RKK Energia

Sputnik launch

The artist impression of the first Sputnik launch. Click to enlarge. Copyright © 2007 Anatoly Zak


The rocket with the first satellite ascends to orbit.

Sputnik's engine cutoff

Second stage of the launch vehicle with the first satellite enters orbit. Click to enlarge. Copyright © 2007 Anatoly Zak


Second stage of the launch vehicle with the first satellite shortly after reaching the orbit. Click to enlarge. Copyright © 2007 Anatoly Zak


Click to enlarge. Copyright © 2007 Anatoly Zak

Sputnik release

Click to enlarge. Copyright © 2007 Anatoly Zak

Sputnik release

First in orbit: The world's first artificial satellite orbits Earth, shortly after separation from the launch vehicle. Click to enlarge. Copyright © 2007 Anatoly Zak


On Oct. 9, 1957, the Pravda newspaper published the first photo of the PS-1 satellite.


Typically for the post-Sputnik euphoria, the Oct. 11, 1957, issue of the Vechernyaya Moskva newspaper run numerous materials on the first satellite, including this photo of Moscovites trying to catch a glimpse of the spacecraft.


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