On Jan. 27, 1967, the crew of Apollo 1 was killed when a fire broke out in their pure oxygen-soaked capsule during a routine pre-launch test. The dangers of an oxygen fire should have been obvious to NASA. It was obvious to the Apollo spacecraft's builder, North American Aviation, who recommended the space agency not run tests with a highly pressurized spacecraft.
It was also a danger the Soviet space agency knew well. In the early days of their training, cosmonaut hopeful Valentin Bondarenko was killed in an eerily similar accident to the Apollo 1 crew.
Cosmonaut training in the 1960s wasn't all that different from the astronauts' training at NASA. Neither nation's space program was sure how men would react to orbital flight and each went to great lengths to prepare its men, both mentally and physically, for the anticipated stresses. For the cosmonauts, the mental training included time spent in an isolation chamber the cosmonaut trainees called the Chamber of Silence.
The Chamber was a spartan room with minimal furnishings: a steel bed, a wooden table, a seat identical to the Vostok capsule's, toilet facilities, an open-coil hot plate, and a limited amount of water for both washing and cooking. Cosmonauts also had leisure materials. Mind games were posted on the walls, and some men were given books or drawing materials. That was it. As the "Chamber of Silence" moniker suggests, sensory deprivation was part of the test. The room was mounted on rubber shock absorbers that muffled any vibrations from movement outside, and the 16-inch thick walls absorbed all outside sounds.
During the test, cosmonauts had no voice communications with the test administrators outside the Chamber. They communicated with doctors by lights. A light would turn on, signaling the cosmonaut to apply medical sensors to his body; turning on an outside light from inside the Chamber cosmonauts could tell doctors when they were ready to start a test. A different light would signal the end of the isolation test. The only sound came from frequent, random interruptions. A sudden blast of classical music was designed to see how the cosmonauts would react to a pleasurable shock.
The test was meant to challenge the cosmonauts' mental stability and ability to adapt to strange situations. The hardest part for the test subjects was waiting – cosmonauts weren't told beforehand how long a test would last. It could run anywhere from a few hours to weeks. Completing the simulated spaceflight atmosphere, the Chamber was pressurized to mimic a Vostok in flight with 68 percent oxygen.
Valentin Bondarenko, known to his friends as a kind man of great athletic abilities who fought to prove he was worthy of the honor of flying in space, was the 17th cosmonaut to go into the Chamber of Silence. On March 23, 1961, his ten day stay in the Chamber ended; a light from technicians outside told him they had started depressurizing the cabin.
Bondarenko spent his last few minutes in the Chamber removing his biomedical sensors, wiping the adhesive off his skin with a rubbing alcohol soaked cotton pad. But his mind was elsewhere, likely outside the Chamber after ten days of mentally strenuous testing. He threw the alcohol soaked cotton pad towards the garbage but missed. It landed on the hot plate's uncovered coil. It wasn't uncommon for cosmonauts to leave the hotplate turned on all the time; many described the small test space as chilly.
The room and everything in it had been soaking in a high oxygen concentration for ten days. A fire sparked and engulfed the room in an instant. Technicians managed to open the door quickly, and exposed to air the fire died down almost immediately but the damage was done. A severely burnt Bondarenko was huddled on the floor. Miraculously, he was still alive.
The doctors that reached the cosmonaut trainee immediately saw the severity of the situation. Bondarenko's wool clothes had melted onto his body, his skin had burned away, his hair had caught fire, and his swollen eyes were melted shut. "It's my fault," he whispered, "I'm so sorry... no one else is to blame."
Bondarenko, wrapped in a blanket, was immediately transferred by a small army of men in uniforms to a hospital in Moscow. The cosmonaut asked for a pain killer. doctors obliged with a shot of morphine in the soles of his feet, the only unharmed part of his body thanks to his heavy boots. But there was nothing anyone could do to save him.
Just 24 years old, Valentin Bondarenko died the next morning. The official cause was shock and severe burns.
In keeping with the Soviets' traditional secrecy, Bondarenko's identity and the nature of the accident wasn't publicized in the West. There's been some speculation that had Soviet space officials shared Bondarenko's story with their American counterparts, the Apollo 1 astronauts could have been spared. But it's unlikely. By the mid-1960s, there was enough American-based research about the hazards of oxygen fires that a warning from the Soviets wouldn't have changed NASA's approach to the "plugs-out" test.
Image: Detail of cosmonaut Alexei Leonov's spacesuit during his historic EVA in 1965, four years after Valentin Bondarenko died in an oxygen fire during training. Public domain.