The Space Shuttle: An Experimental Flying Machine by Ben Evans

Author:Ben Evans
Language: eng
Format: epub
ISBN: 9783030707774
Publisher: Springer International Publishing

Fig. 5.4Black smoke (visible at lower right) pours from the aft segment of the right-hand Solid Rocket Booster (SRB) within milliseconds of Challenger’s liftoff on 28 January 1986.

In the pre-dawn darkness of the 28th, with Challenger brilliantly bathed in the glare of xenon floodlights and primed for launch later that morning, the Final Inspection Team gathered at the pad to begin their lengthy sweep-down of the facility. Their task was to locate any unusual concentrations of ice, debris or damage to the stack which could hinder a successful flight. Armed with their formidable arsenal of cameras, binoculars and infrared sensors, the team checked each surface of the immense vehicle, from the gaseous oxygen vent cap at the top of the ET to the aft skirts at the base of the SRBs, and conditions were so severe that they had to use broom-handles to knock 30-centimeter icicles off the gantry. “There were huge amounts of ice on there,” remembered Shuttle astronaut Don Williams, “like an inch or more; big icicles and frost.” When somebody told Williams that Challenger was ‘Go for Launch’, he thought they were kidding. Temperatures crept a little above zero degrees Celsius as dawn broke. Challenger’s launch that morning was delayed another two hours to allow the Sun to thaw out the copious quantities of ice. “You’ve got to depend on the tactical on-site commander at the Cape to make the call on the temperature and the ice on the pad,” said former chief flight director Randy Stone. “That was the first time in the process that I’m nervous, because this is out of the ordinary. We weren’t in the discussions at all about the temperature effects on the SRBs. It was all taking place behind the scenes.”

STS-51L finally got underway at 11:38 a.m. EST, the thunderous roar of Challenger’s engines and the dazzle of her boosters piercing the morning stillness and pushing the stack into the cold Florida sky. “Here we go,” said pilot Mike Smith from the flight deck, his words recorded for posterity by the on-board intercom. “Shit hot,” added flight engineer Judy Resnik, seated behind him on the flight deck.

The calamity that would engulf Challenger began almost instantly. Half a second after liftoff, as revealed by high-speed photography near the pad and later noted by the Rogers Commission, “a strong puff of grey smoke” was detected, “spurting from the vicinity of the aft field joint of the right Solid Rocket Booster”. The automated camera had picked up the tell-tale signature of both the primary and secondary O-rings failing, disintegrating and streaming away only moments after launch. As if that were not bad enough, the point of failure directly faced the ET and its highly flammable 2-million-liter load of liquid oxygen and hydrogen. Any flame emanating from the compromised SRB could now play on the thin-skinned tank like a blowtorch, igniting its contents in a fireball. The result would be the destruction of Challenger, the incineration of her crew and the obliteration of the entire launch pad.

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