Sputnik 2

• 1. Introduction

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  Sputnik 2 lifted off at 02:30:42 UTC on the 3rd of November 1957, carrying something no spacecraft had ever carried before: a living creature. The passenger was a small part-Samoyed terrier named Laika, formerly called Kudryavka, which means Little Curly. She weighed about 6 kg and had been chosen primarily for her even temperament. The satellite itself was a 4 m cone-shaped capsule weighing around 500 kg, launched just one month after Sputnik 1 had already stunned the world. What drove the Soviet Union to move so fast, with so little time to prepare? Why was there no plan to bring Laika home? And what did Sputnik 2 actually reveal about the space above our atmosphere, both in terms of what it found and what it almost discovered but never claimed?

• 2. Three Weeks to Launch

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  Immediately after Sputnik 1 flew on the 4th of October 1957, Nikita Khrushchev made a demand: he wanted a second satellite ready for the 40th anniversary of the Bolshevik revolution, just three weeks away. Details of the conversation between Khrushchev and OKB-1 head Sergei Korolev vary, but it seems likely that Korolev suggested flying a dog, while Khrushchev pushed hardest on the deadline. The pressure was immense. PS-2, the planned second satellite, had already been built, but it was just a sphere, identical to PS-1.

  Korolev found a practical solution. The R-5A sounding rocket program had been flying dogs on suborbital missions, and a payload container from those missions was simply requisitioned and bolted into the upper stage of the R-7 rocket, directly beneath the PS-2 sphere. No new spacecraft design. No recovery system. No time for one. The 8K71PS launch vehicle, serial number M1-2PS, arrived at the NIIP-5 Test Range on the 18th of October 1957 for final integration. Laika was placed in the payload container at midday on the 31st of October. That same night, the container was attached to the rocket, with an external heating tube keeping the cabin warm against the cold at the launch site.

• 3. Laika's Preparation

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  Laika was selected from ten candidate dogs supplied by the Air Force Institute of Aviation Medicine, all of them already trained for suborbital missions. Because the timeline was so compressed, there was no opportunity to train a dog specifically for this flight. Her backup was a dog named Albina, who had flown on two R-1E suborbital missions in June 1956. Both dogs had telemetry wires surgically implanted to monitor their respiration frequency, pulse, and blood pressure during the mission.

  The pressurized cabin was padded and sized so Laika could lie down or stand. She was fitted with a harness, a waste-collection bag, and electrodes for vital sign monitoring, and she was chained in place. Food and water were provided in gelatinized form. Oxygen came from an air regeneration system. A television camera mounted in the compartment could transmit 100-line video frames at 10 frames per second. None of this was built with the expectation that she would return. No provision was ever made for her recovery.

• 4. Hours in Orbit

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  Sputnik 2 reached an orbit of 212 by 1660 km with a period of 103.7 minutes. At peak acceleration during ascent, Laika's respiration rose to between three and four times her pre-launch rate. Her heart rate jumped from 103 beats per minute before launch to 240 beats per minute during early acceleration. After three hours of weightlessness, her pulse had settled back to 102 beats per minute, though this recovery took three times longer than it had during ground tests, suggesting significant stress.

  The satellite's nose cone jettisoned successfully after reaching orbit, but Sputnik 2 failed to separate from the Blok A rocket stage. Combined with the loss of some thermal insulation, this caused temperatures inside the spacecraft to climb dangerously. Early telemetry showed Laika agitated but still eating her food. After approximately five to seven hours into the flight, no further signs of life were received from the spacecraft.

  For years, Soviet officials offered conflicting explanations for her death: asphyxia, battery failure, or euthanasia by poisoned food, which had been the original plan. In 1999, Russian sources reported she had died from overheating on the fourth day. Then, in October 2002, scientist Dimitri Malashenkov, presenting a paper to the World Space Congress in Houston, Texas, stated that Laika had died by the fourth circuit of the flight from overheating. He quoted the explanation directly: "It turned out that it was practically impossible to create a reliable temperature control system in such limited time constraints."

• 5. Scientific Instruments

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  Sputnik 2 was the first platform capable of making scientific measurements from orbit, and the significance of that capability rivaled the biological payload. The Earth's atmosphere blocks solar X-ray and ultraviolet radiation from reaching ground-based instruments. Solar output also fluctuates too rapidly for suborbital sounding rockets to track continuously. Only a satellite in sustained orbit could observe the complete solar spectrum over time.

  Professor Sergei Mandelstam of the Lebedev Institute of Physics provided two spectrophotometers for the mission, one measuring solar ultraviolet rays and one measuring X-rays. They were mounted in the nose cone, above the PS-2 sphere. Separately, Sergei Vernov, who had built a cosmic ray detector using Geiger counters for the earlier Object D project, insisted that the instrument his Moscow University team had constructed, including team members Naum Grigoriev, Alexander Chudakov, and Yuri Logachev, also fly on the mission. Korolev agreed, but space was so constrained that the instrument was mounted on the Blok A rocket stage with its own dedicated battery and telemetry frequency.

  The cosmic ray detector operated for one week before its battery died on the 9th of November. The photometers, however, proved useless: they had been calibrated for laboratory conditions and were completely oversaturated by orbital radiation from the moment they began operating.

• 6. The Discovery That Got Away

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  The day after launch, the cosmic ray detector reported something unexpected. High-energy charged particle counts jumped from a normal rate of 18 pulses per second to 72 pulses per second at the highest latitudes of Sputnik 2's orbit. Per two articles in the Soviet newspaper Pravda, particle flux also increased with altitude. Researchers now believe Sputnik 2 was detecting the lower edges of what would later be named the Van Allen Belt when it reached the apogee of its orbit.

  The data set had a critical limitation: Sputnik 2 telemetry could only be received while the satellite flew over Soviet territory. For most of each orbit, it passed out of range. Australian observers had also received data when the satellite passed overhead, and Soviet scientists requested it. But the Soviet side refused to share the decryption code that would have let the Australians use their own data. The Australians declined to hand over recordings they could not read themselves. The discovery was never properly mapped.

  Credit for identifying the radiation belts ultimately went to James Van Allen of the State University of Iowa. His instruments on Explorer 1 and Explorer 3 first charted them comprehensively. The belts now carry his name.

• 7. Geopolitical Fallout

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  Massing 508.3 kg, Sputnik 2 dwarfed not only Sputnik 1 but also the American Vanguard satellite, which had not yet flown. The day after Sputnik 2 reached orbit, the Gaither committee met with President Eisenhower to brief him on the situation and urged a more dramatic response than had been given to Sputnik 1. The clear implication was that Soviet missiles were far superior to anything in the American arsenal. Khrushchev pressed that advantage repeatedly. Just six days after the launch, on the 40th anniversary of the October revolution, he boasted in a speech: "Now our first Sputnik is not lonely in its space travels."

  President Eisenhower chose a different posture. According to one of his aides, "The president's burning concern was to keep the country from going hog-wild and from embarking on foolish, costly schemes."

  The mission also ignited a global debate about animal welfare and scientific experimentation. In the United Kingdom, the National Canine Defence League called on dog owners to observe a minute's silence on each day Laika remained in space. The RSPCA received protests before Radio Moscow had even finished announcing the launch. Animal rights groups urged demonstrations at Soviet embassies. Others protested outside the United Nations in New York. American laboratory researchers initially offered some support for the Soviet decision, at least before news of Laika's death became known.

• 8. Final Orbit and Legacy

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  Because of Sputnik 2's large size and its attached Blok A, the combined vehicle was easy to track visually from the ground. In its final orbits, the spacecraft tumbled end over end and flashed brightly as it descended. It reentered the Earth's atmosphere on the 14th of April 1958, at approximately 02:00 hrs, along a line stretching from New York to the Amazon. British ships and three Moon Watch observation posts in New York plotted its track. Witnesses reported it glowing as it fell, with no visible tail until it reached latitudes south of 20 degrees North. Estimates put the average length of the tail at about 50 nautical miles. The spacecraft had circled the Earth 2,370 times over 162 days.

  The path toward bringing animals back alive took time. Korabl-Sputnik 2 returned the first animals safely from orbit in 1960, carrying dogs named Belka and Strelka and proving the life-support systems needed for the crewed Vostok program. A USSR-built engineering model of the R-7 Sputnik 8K71PS is preserved today at the Cosmosphere space museum in Hutchinson, Kansas.