On April 23, 1967, the Soviet space program launched its first-ever Soyuz spacecraft with a person in it. The flight was plagued with technical problems and ended in tragedy. But 50 years later, we're still using descendants of the Soyuz to ferry people and supplies to and from space, most notably the International Space Station. The Soyuz rocket is, by far, the most used and most reliable space launch system humans have ever built. Unfortunately the first Soyuz pilot didn't survive.

Soyuz 1's pilot was cosmonaut Vladimir Komarov, a Soviet test pilot and engineer who had previous experience in space. His voyage on the mission made him the first Soviet cosmonaut to make a second trip into space. He also became the first person to die on a space mission.

The tragedy of Soyuz 1 started with political pressure. Soviet leaders apparently wanted to celebrate Lenin's April 22 birthday with the Soyuz launch. They were also keen to beat the Americans to the moon, and the Soyuz program was akin to NASA's Apollo—aimed at an eventual lunar landing. Apollo was suffering, as the Apollo 1 crew had died that January on the ground in a terrible fire. If the Soviets could get Soyuz running, it would be a massive leap. Despite many technical setbacks on the ground, Soviet leaders pushed for Soyuz 1 to launch.

While cosmonaut Yuri Gagarin (the first human in orbit) was listed as Komarov's backup pilot, there was no way Soviet leaders would allow a national treasure to risk his life in space again. So in a practical sense, either Komarov launched or the mission would be scrubbed. He launched from Baikonur Cosmodrome just after midnight UTC (just after 3:30am Moscow time).

The problems started early. One of the Soyuz craft's two solar panels failed to deploy, leaving the vessel power-starved. The craft's automatic stabilization system was blocked by the failed solar panel, leaving Komarov trying to manually control the orientation of the craft. It didn't work well.

Meanwhile, a secret second Soyuz mission was preparing to launch, carrying three cosmonauts. Mission planners wanted the two craft to meet in space and dock via an EVA. But storms at Baikonur caused mission control to call off the second flight. By Komarov's 13th orbit, directors on the ground decided to end the Soyuz 1 mission early and bring Komarov home.

Komarov tried to descend on his 17th orbit, but the attitude control system fouled up his angle, forcing him to remain in orbit. By his 19th orbit—really his last chance, with dwindling battery power—Komarov reentered the Earth's atmosphere, relying in large part on manual attitude control. He made it work, entering on a viable trajectory. The first ("drogue") parachute deployed, slowing his descent a bit ... but the primary parachute failed to deploy. Komarov manually activated a backup parachute, which tangled with the drogue. With nearly nothing to slow its fall, the Soyuz capsule hit the Earth, killing Komarov instantly.

Komarov's name was included on a commemorative plaque left on the Moon during the 1971 Apollo 15 landing. The plaque honored 14 astronauts and cosmonauts (including the Apollo 1 crew) who died in the pursuit of space.

The tragedy of Soyuz 1 was a huge setback for the Soviet space program, but it wasn't the end of the Soyuz missions. Design flaws were uncovered and fixed, and eventually the Soviet space program had a reliable launch and recovery system. We still use it today. For a look at the modern Soyuz launch system, check out this ESA video: