[The Register] Nedelin Disaster

[The_Unbeliever]

What was the worst disaster in the history of space travel?
- question from Marcus

If you are referring to manned space exploration, the two tragedies that resulted in the greatest loss of life were the destruction of the American space shuttles Challenger and Columbia. Each accident claimed the lives of seven astronauts.

However, another event that occurred in the Soviet Union in 1960 is generally recognized as the single greatest disaster in the history of rocketry. The event was not directly related to manned space flight, but to the development of an intercontinental ballistic missile (ICBM). In the early days of space flight, both the US and Soviet space programs were very much intertwined with the development of ICBMs. These vehicles were designed to launch nuclear warheads over great distances, leaving no part of the world safe from the threat of nuclear destruction. However, the technologies pioneered for these weapons of war served a secondary purpose of providing the first generation of rockets for space exploration.

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Nevertheless, technical problem with the flight control system continued to plague the test preparations. Despite these obstacles, the rocket was moved from the assembly building to the launch pad at a location called Site 41 on October 21. At this point, fueling of the rocket with its toxic and highly corrosive propellants began. Proper safety protocols insisted that all non-essential personnel evacuate the area during fueling operations in case of an accident. However, Nedelin ignored these regulations and reportedly set up a chair at the pad from which he could oversee the arrangments. Approximately 150 other civilian and military personnel also stayed at the site under his direction.

As preparations for the launch continued, increasingly more fuel leaks and electrical problems began to emerge. On October 23, a number of electrical faults occurred that prevented the propellant pumps from working properly. The rocket would have to be drained of fuel before beginning repairs, but Marshal Nedelin refused to do so since it would delay the launch by at least several hours. He instead ordered workers to perform their repairs on the rocket while its dangerous propellants were still aboard.

And so the stage is set. What happens next is horrific.

[SUP]R-16 ICBM[/SUP]​

Repairs continued to drag on the next day prompting Nedelin to demand to be taken to the pad "to figure out what's going on." In addition to Nedelin and his subordinates, Yangel and a number of visiting dignitaries were also taken to the pad to personally direct the pre-launch operations. The presence of so many powerful figures put great stress on the workers, and the situation was only made worse by pressure from Moscow to launch as soon as possible. Many tests and other operations were being conducted simultaneously, and safety procedures were neglected to save time.

The most significant oversight involved a device called the Programming Current Distributor (PTR) that activates various systems on the rocket. Following a test, the PTR was accidentally set to the wrong position. This mistake caused the batteries and propellant lines on the rocket to be activated, meaning that only a single valve prevented the rocket engines from being ignited prematurely. When a technician accidentally reset the PTR, that last safeguard was removed, and a horrible sequence of events was set into motion.

At about 6:45 PM, with some 250 personnel and visitors crowded around the launch pad, the second stage rocket engine of the R-16 ignited. The exhaust immediately ripped through the fuel tank in the first stage, creating a massive explosion that sprayed acidic chemicals across the launch complex. The luckiest were those who were instantly incinerated in the ensuing fireball that engulfed the rocket. Others died more slowly as they were burned while trying to escape through the raging inferno. Still more were able to evacuate the immediate vicinity only to be suffocated by the poisonous gases created by the burning propellants.

[SUP]Catastrophic explosion of the R-16[/SUP]​

Massive explosions continued to rock the launch pad for about 20 seconds, and the subsequent fires lasted for two hours. The blast was reportedly visible as far as 30 miles (50 km) away.

Rest of this fascinating and sad piece of history can be found here : http://www.aerospaceweb.org/question/spacecraft/q0179.shtml

It was linked to by The Register's fascinating article about rocket history : http://www.theregister.co.uk/2013/04/02/race_for_space_1/