Sputnik-2 in orbit



The launch vehicle designated 8K71PS No. M1-2PS lifted off on Nov. 3, 1957, at 05:30:42 Moscow Time, according to one source (51) and at 07:22 Moscow Time, according to the other. (52)

The command to shut down engines of the rocket's core stage was issued as soon the main engine run out of oxidizer, or 297 seconds after liftoff. At that moment, the vehicle was flying 7,945.3 meters per second, with the angle 0.12 degrees toward a local horizon. (A secret note No. SK-3/2468 to the Central Committee listed a final velocity of 7,960 meters per second, or 190 meters per second faster than that of the first satellite.) The Sputnik-2 successfully reached 225 by 1,671-kilometer orbit with an inclination 65.3 degrees toward the Equator. (227)

According to the SK-3/2468 document, a total of five sites in Moscow, Dnepropetrovsk, Kapustin Yar, Novosibirsk and Tyuratam were involved in processing of telemetry data from the spacecraft. Soviet anti-aircraft radar, stations of the Ministry of Communications and some optical assets were involved in tracking the mission. Radio amateurs also contributed to tracking.

During initial two orbits, Soviet ground controllers used optical and radio equipment to track the second satellite, producing less than accurate results. During the third orbit, controllers managed to improve tracking drastically, apparently with the help of the theodolite data from a US ground station in Perth, Australia. The information was reportedly intercepted by the Chinese and then transferred to the Soviets. (262)

As telemetry later revealed, Laika's heart was beating 260 cycles per minute, or three times higher than normal during her ride to orbit. Frequency of her breath also rose 4-5 times above usual. The dog was probably terrified by the roar of the engines below and violent shaking of the cabin on its way up. Overall, however, Laika survived the launch unscathed. (248) Initially, Soviet publications claimed that dog lived in orbit for a week.

Sputnik-2 in orbit

Sputnik-2 orbits Earth.

Decades later, several Russian sources revealed that Laika survived in orbit for four days and then died when the cabin overheated. According to other sources, severe overheating and the death of the dog occurred only five or six hours into the mission. (248, 261)

The secret note SK-3/2468 to the government said that during first three orbits telemetry had shown normal breath and heartbeat of the dog. During the third orbit "movements" of the animal were registered, coinciding with a sharp increase of temperature inside the cabin, reaching 43 degrees. The telemetry received on the second day during the 15th, 16th and the 17th orbit had shown no data from sensors measuring blood pressure, heartbeat and breathing. Yet, cardio sensor did reportedly indicate that the dog was still alive. Finally, as of 5 a.m. (Moscow Time) on November 6, telemetry showed no signs of heartbeat, pressure or movement.

Initial telemetry also showed that UV and X-ray payloads onboard the second satellite were switching their filters and were sending calibration signals as planned. It was not clear from the document whether these instruments had delivered any useful data.

Six days after the launch, on November 10, 1957, Sputnik-2 exhausted its batteries and ceased transmitting data. With all systems dead, the spacecraft continued circling the Earth until April 14, 1958, when it reentered the atmosphere after 2,570 orbits (2,370 orbits according to other sources (2, 248) or 162 days in space. (227) Many people reportedly saw a fiery trail of Sputnik-2, as it flew over New York and reached the Amazon region in just 10 minutes during its reentry. (517)


Next chapter: Aftermath of the Sputnik-2 mission

Written by Anatoly Zak

All rights reserved.

Last update: August 13, 2020



Sputnik-2 enters orbit

Sputnik-2 enters orbit. Watch animation: Streaming QuickTime. Copyright © 2007 Anatoly Zak


Sputnik-2 launch

Sputnik-2 launch

Laika's launch

Sputnik-2 launch

Sputnik-2 launch

Sputnik-2 launch

The second Soviet satellite lifts off from Baikonur on Nov. 3, 1957, at 05:30 Moscow Time (it was 07:30 in the morning local time) Credit: RKK Energia

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