00:00Depressurized, in space, with less than 20 seconds to react while descending back to Earth.
00:06These three cosmonauts were caught in history's most horrific disaster to occur in space.
00:12What started as a carefully coordinated mission ended in pure horror.
00:17What happened next is truly disturbing.
00:19On June 29, 1971, aboard Salyut-1, the world's first orbiting space station,
00:30Georgi Dobrovolski, Vladislav Volkov, and Viktor Pastayev were preparing to return home after 22 days of scientific experiments
00:39and undocked from the station, ready to re-enter the Earth's atmosphere.
00:43But while the USSR celebrated their historic mission back on Earth with controlled television broadcasts,
00:51the crew was about to make history for a much darker reason.
00:55They only had four days' notice before launch,
00:58because a key member of the original crew was believed to have tuberculosis.
01:02As the backup team, two were in space for the first time,
01:06leading to clashes between Commander Dobrovolski and the more experienced flight engineer, Vladislav Volkov,
01:13To make matters worse, an electrical fire on June 16 forced Salyut-1 onto reserve power.
01:20Ground control insisted the station was safe, but the cosmonauts weren't convinced.
01:25They wanted to end the mission early.
01:27This sudden decision might have been something out of fear,
01:31fear of something the Soviet government refused to acknowledge.
01:34However, they had no idea what was about to happen.
01:37Their highly anticipated space mission was about to turn into a nightmare.
01:43Known as the Torre-Bert Recordings,
01:46a skilled team of international volunteers monitored Soviet transmissions throughout the 1960s.
01:52Their evidence suggests the Soviet Union covered up multiple deaths of cosmonauts drifting off into space.
01:59That fear may have been one of the reasons why the cosmonauts requested to leave.
02:04But ground control refused.
02:06The men stayed, continuing their experiments, and things quickly became much, much worse.
02:12Relentless stress and sleep deprivation took a toll on the crew.
02:16Most worrying was that Volkov, the most experienced man, grew irritable and started making critical mistakes.
02:23Over the next week, doctors kept a close watch on their declining mental state.
02:28However, their physical well-being was a growing concern.
02:32Daily exercise was vital in zero-gravity conditions to prevent muscle deterioration.
02:37But the treadmill rattled Salyut 1's solar panels and antennas, so they avoided using it throughout their stay.
02:44By June 24th, the exhausted crew had met their research goals.
02:49So, ground control decided to end the mission six days early, planning to return on June 30th, 24 days after its launch, including their time in transit.
02:59The news instantly lifted the cosmonauts' spirits.
03:03After loading their research onto Soyuz 11, they powered up the spacecraft on June 29th and began preparing for their descent.
03:10During re-entry, the ship would separate into three compartments, the orbital, service, and descent modules.
03:17They were segmented using hatches and automatically ejected when six explosive bolts fired sequentially, or one at a time.
03:25It was into the extremely cramped descent module that the crew boarded, wearing minimal equipment to fit inside the small space.
03:34But when the time finally came to undock, Volkov struggled to seal the descent module hatch.
03:39With the help of ground control, he managed to tighten it just enough to pass a pressure test, and Dobrovolsky undocked Soyuz 11 at 1828.
03:49It was supposed to be a straightforward leg home.
03:52Little did they know, something was about to go terribly wrong.
03:56At 2235, Dobrovolsky ignited a retro rocket for 187 seconds, slowing the spacecraft for re-entry.
04:04Nine minutes later, at 105 miles altitude, or 169 kilometers, Soyuz 11 started the separation sequence, but the explosive bolts malfunctioned, firing all at once.
04:16The cosmonauts had no warning.
04:19A violent blast jolted the descent module with extreme force, opening its pressure equalization valve by the slimmest margin.
04:28As alarms screamed, the cabin instantly lost 99% of its pressure, sucking air into space at over 600 miles, or 965 kilometers per hour.
04:39The men turned off the module's radio transmitter and unstrapped from their seats, frantically trying to locate the hissing leak.
04:47But without pressure suits, their bodies were defenseless.
04:51Oxygen wrenched from their lungs and bloodstreams, causing their breathing rates to triple within four seconds.
04:57Each desperate gasp only worsened their suffocation, starving their brains of fuel.
05:03Soon, their neurons began to misfire, and nitrogen bubbles formed in their veins.
05:08They screamed in agony, twitching uncontrollably as stabbing pains tore through their joints.
05:15The sudden pressure drop ruptured blood vessels in their eyes and ears.
05:19Streaks of red trickled down their faces, and the men became deaf to the horror unfolding around them.
05:26Dizzy and confused, the cosmonauts tried to save themselves, but they were losing fluids.
05:31Moisture inside their eyes and mouths boiled, leaving a bubbling sensation on their tongues.
05:37Within ten seconds of the blast, their vision blurred, tunneling into darkness.
05:42The last thing the cosmonauts saw was the cockpit fogging over.
05:46One by one, they lost consciousness, their hearts still beating erratically, struggling against severe internal bleeding.
05:54In the meantime, the world looked on with anticipation, expecting their triumphant return.
05:59When Soyuz 11 broke through Earth's atmosphere at 2347, its telemetry showed no visible damage.
06:08Mission Control thought it was only a matter of time before the cosmonauts resumed radio contact.
06:13However, they began to fear the worst, as they tracked its progress beyond the usual blackout zone,
06:19where superheated plasma briefly cuts off signals.
06:22The module silently completed its automated descent, landing in central Kazakhstan 25 minutes later.
06:29Recovery personnel touched down shortly after and knocked on the module to give the cosmonauts a hero's welcome.
06:36But they didn't respond.
06:38The researchers opened the hatch, only to find vacant faces with dark blue patches staring back at them.
06:45Remarkably, Postoyev was found near the ventilation valve, whereas Dobrovolsky was tangled in his seat straps with a checklist nearby.
06:54Despite the devastating effects of decompression, they remained composed throughout it all.
07:00Dobrovolsky was still warm to the touch, so the recovery team immediately performed CPR on the crew.
07:06But it was too late.
07:07Their condition was reported to Mission Control using the coded message 111, a numerical health status system which meant fatal.
07:17The Soviet government transported their remains to the Burdenko Main Military Clinical Hospital for autopsies.
07:24The findings painted a grim picture.
07:27The cosmonauts had succumbed to asphyxiation.
07:30However, they also suffered hypoxia and catastrophic organ failure from blocked circulation.
07:36The Soviet Union broke the news a few hours later and held a state funeral in Moscow's Red Square on July 1st.
07:44But behind closed doors, engineers made a damning discovery.
07:48The cabin hadn't been tested for worst-case structural shocks, and its pressure valve was a known death trap.
07:55The mission's original commander, Alexei Leonov, didn't trust the valve to close automatically.
08:01He'd encountered issues in the simulator and advised the crew to close it manually.
08:05But it was buried beneath a cockpit seat, taking over a minute to close, 20 seconds longer than the crew survived.
08:13Without an emergency override or warning system, they never stood a chance.
08:18The Soviets covered up the design flaws to protect national pride.
08:22After two years of speculation, they finally revealed the truth to NASA during the 1973 Apollo-Soyuz project.
08:30In exchange, NASA shared their findings from the Apollo 13 disaster.
08:35The tragedy led to a complete redesign of Soyuz's craft.
08:39Pressure valves were reinforced, emergency pressure equipment was added,
08:43and an accessible ventilation valve handle was installed in future cockpits.
08:48Most notable was mandatory pressure suits, a practice that saves lives to this day.
