When the Soviet Union launched Laika aboard Sputnik 2 in 1957, the world was told she had survived for days. Decades later, the truth emerged: she had died within hours, after the capsule overheated in orbit.

On 3 November 1957, the Soviet Union launched a small stray dog named Laika aboard Sputnik 2, making her the first living creature to orbit the Earth. The world was told she had lived for days in space. The truth, confirmed only decades later, was that she died within hours, when her capsule overheated.

A mission with no way home

Sputnik 2 was built in a hurry. Nikita Khrushchev wanted a second triumph to follow the first Sputnik within weeks, in time for the fortieth anniversary of the October Revolution, and engineers had barely a month to design and assemble the spacecraft.

There was no plan to bring it back.

Sputnik 2 carried no re-entry or recovery system, and Laika was never going to return. The intention was that she would survive for several days, long enough to show that a living animal could endure launch and weightlessness, and then die in orbit once her oxygen ran out. That part of the mission was, in its grim way, by design.

The story the world was given

What the public heard was a gentler version. Soviet statements said Laika had survived in orbit for several days. The accounts varied: that she died around the sixth day as the oxygen gave out, or that she had been painlessly put to sleep before then.

For decades this was the accepted history, a week-long flight and a hero dog. The inconsistencies in the official line were left unexplained, a product of Cold War secrecy that kept the mission’s real data out of view.

What actually happened

The record was corrected in October 2002. At a space conference in Houston, the Russian scientist Dimitri Malashenkov, who had worked on the mission, reported that Laika had died only about five to seven hours after launch.

The cause was heat.

The rocket’s core stage had failed to separate cleanly from the capsule, which disrupted the spacecraft’s thermal control, and the cabin temperature climbed well past 40 degrees. Laika died of overheating and stress, on roughly her fourth orbit, not after the better part of a week.

Why it stayed buried

The real circumstances served no purpose during the Cold War, and the surviving-for-days account was simply the better story to tell. The underlying data were not published in the West, and it took the end of the Soviet Union, and the willingness of the people involved to speak, before the full picture came out.

What it left behind

The flight did establish something that mattered. A mammal could survive the violence of launch and the strangeness of weightlessness, at least for a while, which was a necessary thing to know before sending people up. Laika’s name endured, and the Soviet Union later marked it with monuments.

But the death, and the way it was handled, became a turning point in how the use of animals in spaceflight was judged. Oleg Gazenko, one of the scientists behind the mission, said years afterward that the more time passed, the more he was sorry about it, and that they had not learned enough from the flight to justify the death of the dog. It is about as honest a verdict on the mission as anyone involved ever offered.