Baikonur launchpad explosion
Baikonur launchpad explosion, explosion of a Soviet intercontinental ballistic missile on October 24, 1960, at a launchpad at the Baikonur Cosmodrome in what is today Kazakhstan. An unknown number of people, with official estimates ranging from 60 to 120, were killed, and the disaster is considered the worst single accident in the history of rocket science.
At the time of the accident, the Soviet Union was engaged with the U.S. in not only a space race but also an arms race, and the rocket launching site at the Baikonur Cosmodrone was at the heart of both for the Soviet Union. In 1960, a prototype of the R-16 intercontinental ballistic missile, designed by Mikhail Kuzmich Yangel, was being prepared for testing. This missile was some 30 m (98 ft) in length, weighed 141 tons, and had a range of 11,000 km (6,835 mi). Mitrofan Nedelin, head of the Soviet Union’s strategic missile forces, decided that it was necessary to speed up the test launch of the missile so that it could take place in time for the anniversary of the October Revolution, on October 24.
In an effort to conceal its true location from the West, the Soviet Union deliberately named the Baikonur launch site after a mining town that was in fact 320 km (200 mi) away.
Inevitably this meant overlooking safety procedures, and testing began to overlap with preparations for launch. The R-16 used fuel that had a high boiling temperature, which enabled the fuel to be stored. It used a hypergolic—that is, self-igniting—pair, with unsymmetrical dimethylhydrazine as the propellant and nitrogen tetroxide as the oxidizer, a combination so corrosive and toxic that it was called the devil’s venom. There were problems with the electrical guidance system, and workers were required to continue working on the system, no matter how long it took to get it ready. When the fueled missile was ready to launch, other workers were sent into the rocket to verify that the second-stage disc had correctly ruptured to allow the fuel components to move toward the combustion chamber. However, the technicians discovered that a first-stage disc had ruptured instead and that there was a small fuel leak. At this point, the launch should have been canceled and the fuel drained for repairs, but Nedelin ordered that repairs be done while the missile was still on the launchpad.
Work to mend the missile went on for the next 24 hours. The countdown began, and this time it was decided to rupture the second-stage discs manually rather than automatically. In the meantime, workers swarmed over the rocket, correcting electrical problems that continued to pop up, while some 150 high-ranking spectators, including Nedelin himself, were seated near the launchpad. As electrical repairs were being carried out, the resetting of a switch resulted in a short-circuit that caused the second-stage engine to ignite; its exhaust ripped through the fuel tank on the first stage, producing a massive explosion and fireball that was reportedly seen some 50 km (30 mi) away. Most of the survivors, among them Yangel, were those who had stepped away from the launchpad for a cigarette break.
The Soviet Union took measures to prevent anyone from finding out about the catastrophe. It was reported that Nedelin had perished in an airplane crash, and relatives of other victims were told similar stories. However, seismic sensors and intelligence informants gave U.S. intelligence agencies and Western news organizations some understanding that an explosion had taken place. The Soviet Union finally acknowledged the catastrophe in a magazine article in 1989, and only after the fall of the Soviet Union in 1991 did more complete information become available.