In the spring of 1967, the Soviet Union was getting ready to celebrate May Day, one of its most important holidays. And the celebration would be preceded by a spectacular mission in space: Two Soyuz spacecraft would rendezvous and dock, and two cosmonauts would walk in space.

Soyuz was designed to carry cosmonauts to the Moon. But three unmanned tests had all resulted in failure. Even so, there was pressure to get on with the first manned flights. So 40-year-old cosmonaut Vladimir Komarov launched aboard Soyuz 1 on April 23rd, 1967.

But the craft was a dud, rushed into space before it was ready. After launch, one of its solar panels failed to open, and systems designed to aim and maneuver the Soyuz failed as well.

The launch of Soyuz 2 was canceled, and controllers set about trying to get Komarov back home. More problems delayed retro-fire by two orbits. Finally, after a day in space, Komarov fired his rockets and headed home.

After reentry, though, the main parachute got stuck. A backup deployed, but got tangled with a smaller chute and never opened. Soyuz 1 hit the ground at 90 miles per hour, killing Komarov. Moments later, braking rockets fired, engulfing the capsule in flames.

It took 18 months to redesign the Soyuz and get it back into space — a delay that scuttled any chances of winning the Moon race. Today, though, the Soyuz continues to fly — carrying Russians, Americans, and others to the International Space Station.

Script by Damond Benningfield