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Friday, June 23, 2023

The Inevitable End of the Titan Submersible

I can't help thinking that the fate of the Titan deep-sea submersible is an example of the Principle of Imminent Collapse. The designers chose a number of characteristics and construction innovations and build a device which would ultimately fail catastrophically. All it took was The Nudge.

The Principle of Imminent Collapse states that everything in our experience is on the verge of failure and all it takes is the Nudge to make it collapse. In so many examples this principle manifest itself in the worst ways possible. In other articles I present some famous examples.

Barring some as yet unknown vector of failure such as a torpedo, a giant squid or Neptune himself, The Titan succumbed to the pressures of the deep and in an instant crushed the interior of the vessel. The failure would have been preceded by a few moments of creaking noises then a WHOOSH. The 96 hours of oxygen and life support would ultimately be unnecessary.

Unless the mission involved a dive too deep the failure would have been unexpected yet not unpredictable. Pressure vessels have a useful life which can only be exceeded at the peril of those around it. The two kinds of pressure vessels are ones designed for internal pressure like a SCUBA tank or an acetylene welding rig. The other is the one for external pressure such as a submarine. The Beebe-Barton Bathysphere  was a steel ball-shaped container which was lowered on a cable into the icy dark depths of the ocean. It set depth records with its missions. It had communications and power from the surface and was retrievable by the surface operator.

The Titan was a free dive device which had supposedly redundant system to self-rescue in the event of mission ending conditions. The one which could not be survived is the one which ended its time. All materials undergoing cyclic stresses are subject to material fatigue even when the ultimate strengths are not exceeded. Jet engines are an exercise in predicting fan blade failures before they happen and explode the engine in flight. Every aircraft which flies above the altitude where cabin pressurization is required experiences the cyclic expansion and relaxation of the fuselage. The metal will eventually crack. Those cracks will propagate until the structure fails.

This is why the Liberty Bell in Philadelphia in not rung any more. Its crack would get longer with each and eventually peal a large chunk of the bell would fall off. The contraction and expansion of the composite materials of the Titan submersible introduced regions of delamination which would only be recognized by the sensors place on the hull. They knew there was a problem that needed constant monitoring.

Hubris is one of the causes of the Principle of Imminent Collapse manifesting early failures. They believed they had way to know when enough was enough. The problem was the interval between first warning and failure was way too short. If there was any earlier indications of imminent collapse and they ignored them, they were living on borrowed time. In such hostile environments there is very little time to decide to abort and get into shallower water. Reports were made that some technical staff had misgivings about the integrity of the craft.

It was a case of "one time too many." It was also a case that the immediately previous mission was on the verge of the same failure and that crew got lucky. The Titan was a million dollar piece of hardware. It needed to make a minimum number of missions in order to be financially sustainable. Its last mission exceeded the parameters and failed. Unfortunately one never knows when the Principle of Imminent Collapse will determine the last mission. Only the humans can decide to call it a day and retire the equipment before the inevitable failure.

 

 

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