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| A Sputnik 2 launch cover from "KNIGA", postmarked in Moscow with a hand cancel dated November 3, 1957. The postmark was backdated because the successful launch of Sputnik 2 was not made public until after it had taken place. |
Sputnik 2, launched on November 3, 1957, was the Soviet Union's second artificial satellite and the first spacecraft to carry a living animal into Earth orbit. It carried Laika, a small female stray dog, and was launched only 32 days after Sputnik 1. It was hurriedly developed after the success of Sputnik 1, largely to capitalize on the political and propaganda impact of placing a living creature in orbit.
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| Photo: A photograph of the interior of Sputnik 2 spacecraft. |
Laika was housed in a pressurized biological compartment equipped with life-support equipment, food, temperature regulation, and medical monitoring instruments. Her heart rate, respiration, blood pressure, and movements were monitored during the flight. The spacecraft also carried scientific instruments to study cosmic radiation, solar radiation, and the environment of near-Earth space.
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| A Sputnik 2 First Day Cover, postmarked in Moscow with a hand cancel on December 30, 1957. The set includes four stamps featuring the same design in different denominations.
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Laika’s flight was intended to determine whether a living animal could survive launch and orbital flight. Her vital signs initially reflected the stresses of launch before stabilizing in weightlessness. However, a failure of Sputnik 2’s thermal-control system caused the cabin temperature to rise, and later telemetry analysis established that Laika died from overheating and heat exhaustion only a few hours after reaching orbit. Early Soviet accounts falsely claimed that she survived for several days before being euthanized.
Sputnik 2 was never designed to return Laika to Earth and had no recovery or controlled reentry system, largely because the mission was developed in an exceptionally short time.
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| A cover commemorating Sputnik 2's achievement of completing 2,000 orbits in space, postmarked with a black Moscow special hand cancel dated March 21, 1958. |
Despite Laika’s death, Sputnik 2 demonstrated that biological monitoring and life-support systems could function in orbit. Its instruments also collected scientific data for about a week, detecting radiation surrounding Earth. The discovery of the Van Allen radiation belts was subsequently credited to the U.S. Explorer 1 mission, launched in January 1958.
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| A cover featuring a sketched portrait of Laika, commemorating Sputnik 2’s completion of 2,000 orbits, postmarked with a black Moscow special hand cancel dated March 21, 1958. |
Sputnik 2’s batteries were exhausted on November 10, 1957, ending communications and data transmission. The satellite remained in orbit until reentering the atmosphere on April 14, 1958, nearly six months after launch.
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| A postcard featuring an illustration of Laika, commemorating the third anniversary of the Sputnik 2 launch, postmarked in Moscow with a hand cancel on November 3, 1960. Also postmarked with a black Moscow special cancel. |
