PARIS • With a wall of red-orange flames rapidly advancing and Notre-Dame's vast chambers reaching oven-like temperatures, the commander of the Paris fire brigade made a painful choice on Monday evening. He told his firefighters to retreat.
Losing a beloved medieval relic would be devastating, of course, but losing human lives in a hopeless effort to save the building would be even worse. But Commander Jean-Claude Gallet had a backup plan: Colossus, a 500kg tank-like robot with the ability to venture into danger zones where conditions would quickly kill a person.
Using a motorised water cannon capable of firing 2,500 litres per minute, Colossus took aim at the stone walls of the ancient cathedral and began spraying.
In an interview with the Times of London, Commander Gallet credited the fire-fighting robot with lowering temperatures inside the glass-filled nave and saving the lives of its human counterparts as an even greater disaster loomed.
"Time was against us, the wind was against us, and we had to get the upper hand," Lieutenant-Colonel Gabriel Plus, a spokesman for the Paris fire brigade, told the paper.
"The priority we set was to save the two belfries. Imagine if the timber of the belfries had been weakened and the bells had collapsed. That was really our fear. In the beginning, it was not impossible to imagine that the cathedral structure could collapse," he said.
Shark Robotics, the French company that created the machine, says the Colossus - which is 76cm wide and 160cm long - can carry 544kg and be operated from over 300m away.
Controlled using a joystick, the machine is waterproof, fireproof and can even withstand thermal radiation, according to the company.
It can crawl up stairs. The machine's lithium ion batteries can last for up to eight hours, and the robot can be equipped with cameras, sensors and a smoke-extracting fan.
The machine's heroic role in the Notre-Dame fire may be remembered as the beginning of a new era of robotic firefighting.
Colossus is far from the only robotic firefighter available for action.
In China, video footage has emerged of firefighting robots taking part in drills alongside human firefighters.