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Sputnik 2

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Sputnik 2
Sputnik 2
Operator Soviet Union
Major contractors OKB-1
Mission type Earth Science
Satellite of Earth
Orbits ~2,000
Launch date November 3, 1957 at 02:30:00 UTC
Launch vehicle R-7/SS-6 ICBM
Mission duration 162 days
Orbital decay April 14, 1958
COSPAR ID 1957-002A
Homepage NASA NSSDC Master Catalog
Mass 508.3 kg (1,120 lb.)
Orbital elements
Semimajor axis 7,314.2 km (4,545 milies)
Eccentricity .098921
Inclination 65.33°
Apoapsis 1,660 km (1,031 miles)
Periapsis 212 km (132 miles)
Orbital period 103.7 minutes
Dog Laika: Biological data
Geiger counters : Charged particles
Spectrophotometers: Solar radiation (ultraviolet and
x-ray emissions) and cosmic rays

Sputnik 2 (Russian: Спутник-2, Satellite 2) was the second spacecraft launched into Earth orbit, on November 3, 1957, and the first to carry a living animal, a dog named Laika. It was a 4 meters (13 feet) high cone-shaped capsule with a base diameter of 2 meters (6.5 ft). It contained several compartments for radio transmitters, a telemetry system, a programming unit, a regeneration and temperature control system for the cabin, and scientific instruments. A separate sealed cabin contained the dog Laika.

Engineering and biological data were transmitted using the Tral D telemetry system, which would transmit data to Earth for a 15 minute period during each orbit. Two photometers were on board for measuring solar radiation (ultraviolet and x-ray emissions) and cosmic rays. Sputnik 2 did not contain a television camera; TV images of dogs on Sputnik 5 are commonly misidentified as Laika.

Mission profile

Postage stamp of the USSR, «Спутник-2»

Sputnik 2 was launched into a 212 x 1660 km (132 x 1031 mile) orbit with a period of 103.7 minutes on an essentially unmodified ICBM R-7, similar to the one used to launch Sputnik 1. After reaching orbit the nose cone was jettisoned successfully but the Blok A core did not separate as planned. This inhibited the operation of the thermal control system. Additionally some of the thermal insulation tore loose causing interior temperatures to reach 40 °C (104 °F). It is believed Laika survived for only a few hours instead of the planned ten days because of the heat. The orbit of Sputnik 2 decayed and it reentered Earth's atmosphere on 14 April 1958 after 162 days in orbit.


The first being to enter orbit was a female part- Samoyed terrier originally named Kudryavka (Little Curly) but later renamed Laika ("Barker"). She weighed about 6 kg (13 lb). The pressurized cabin on Sputnik 2 allowed enough room for her to lie down or stand and was padded. An air regeneration system provided oxygen; food and water were dispensed in a gelatinized form. Laika was fitted with a harness, a bag to collect waste, and electrodes to monitor vital signs. Early telemetry indicated Laika was agitated but eating her food. In October 2002 it was revealed by Russian sources that Laika had already died after a few hours from overheating and stress, not suffocation as is commonly believed. If neither had taken place, Russian Mission Control had planned to euthanize Laiki with posioned food, as she would have burned up in the atmosphere during reentry. The mission provided scientists with the first data on the behaviour of a living organism in the space environment.

Sputnik 2 and the Van Allen radiation belt

Sputnik 2 detected the Earth's outer radiation belt in the far northern latitudes, but the significance of the elevated radiation was not realized. In Australia, Professor Harry Messel intercepted the signals but the Soviets would not provide the code and the Australians would not send the data. In 1958, with Sputnik 3, they began to cooperate and confirmed the findings of the US satellites Explorer 1, 3, and 4.

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