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Controllers both at the Cape and in Houston intently monitored Challenger's roaring ascent for a different reason. It is the most critical and most dangerous phase of a space mission. "When you have that much power, you have to respect it," said Flight Director Jay Greene in Houston. "If you get complacent about the launch phase, you don't understand what's going on." In the shuttle, the crew was about to be jammed back into their couches by three times the force of gravity. Their immediate fate was out of their hands.
"Houston, we have roll program," declared Commander Scobee. The flight was only 16 seconds old.
"Roger, roll Challenger," acknowledged Mission Control's Richard Covey in the professional tones of all air controllers. Like a fly clinging to a caterpillar, the shuttle turned gracefully on its back as the tank and the boosters assumed the proper downrange course for entering orbit.
At 35 seconds, Challenger's engines were throttled back to 65% of full power to pass through the zone of high turbulence. Nesbitt announced that the situation was "nominal," as NASA calls it: "Three engines running normally. Three good fuel cells. Three good APUs (auxilliary power units). Velocity 2,257 ft. per second (1,538 m.p.h.). Altitude 4.3 nautical miles. Downrange distance three nautical miles."
"Challenger, go with throttle up," said Covey after 52 seconds of flight. That was not an order; it meant that the engines had automatically reached full power and systems were go. Based on the performance of earlier engines, Challenger actually reached 104% of the older standard. The power-up meant that the shuttle had begun to endure the greatest stress of physical forces in its ascent.
"Roger, go with throttle up," Scobee confirmed. The message came at 70 seconds into Challenger's flight.
NASA's long-range television cameras had been following Challenger's shiny * white rocket plume, recording the graceful roll that had awed the spectators. But then the cameras caught an ominously unfamiliar sight, imperceptible to those below. However different those photographs later looked to viewers of the endless taped replays, NASA analysts said that an orange glow had first flickered just past the center of the orbiter, between the shuttle's belly and the adjacent external tank. This was near the point where the tank is attached to Challenger. Milliseconds later, the fire had flared out and danced upward. Suddenly, there was only a fireball. Piercing shades of orange and yellow and red burst out of a billowing white cloud, engulfing the disintegrating spacecraft.
Snaking wildly out of control, the two boosters emerged from the conflagration, both clearly intact. They veered widely apart, leaving yellow- orange exhaust glows and gleaming white trails behind them. The configuration resembled a giant monster in the sky, its two claws reaching frantically forward.