_Live From Cape Canaveral_ - Jay Barbree [66]
“Eagle, Houston,” Charlie Duke’s voice shot across space at the speed of light, 186,300 miles per second. “If you read, you’re GO for powered descent.”
At that precise second, Apollo 11’s lunar module was coming around from the backside of the moon, where its receiving antennas had been blocked for twenty-two minutes.
Armstrong and Aldrin were not alone up there. Their crewmate, Michael Collins, was fifty miles out in front of them, orbiting the moon in their command ship, Columbia. Collins had heard the vital message clearly.
“Eagle, this is Columbia.” His words flashed instantly into the spacesuit helmets worn by Armstrong and Aldrin. “They just gave you a GO for powered descent.”
“Roger,” Armstrong acknowledged.
The two men glanced at each other and instinctively tugged at the cinches of their body harness. They were ready to go land on the moon as green-bright digits changed constantly before them, numbers flashing on Eagle’s flight panel in a breathless blur.
This was PDI!
Powered descent initiate.
On Earth, billions prayed.
Neil Armstrong and Buzz Aldrin braced themselves for the shock of ignition.
Flame gushed beneath their feet. Inside Eagle the two astronauts, who had been weightless for four days, were once again in a gravity field. Their arms sagged. Legs settled within their suits. Feet pressed downward in their boots.
Eagle was in full power, blasting away weight and mass, slowing, slowing.
Headsets crackled. Mission Control was calling. “Eagle, Houston. You are GO. Take it all at four minutes. You are GO to continue powered descent.”
But all was not well.
Back on Earth, Mission Control was thick with tension.
Those manning the front row of consoles were in what was known as the “trench.” This was where final decisions were made.
Eyes were on a twenty-six-year-old computer master named Steve Bales. During a mission he was GUIDO, the acronym for guidance officer.
Today, Bales had come to work early. It could be the most important, demanding, and exciting day of his life. And he knew that twenty-four-year-old Jack Garman was in the back room. Both were experts on the lunar module’s onboard computers.
Deep within the bowels of Eagle, these essential computers measured all the electronic and mechanical forces needed to reach the lunar surface safely. And every flight controller in Mission Control knew these computers contained sensitive watchdogs—alarm systems to detect anything wrong.
Bales and Garman were familiar with each of those alarms and what they meant, and at the moment, everything they monitored aboard Eagle was green and go.
Then, within a flash, Eagle’s computers shrilled madly.
Alarm!
“Program alarm!” Buzz Aldrin shouted the warning. “It’s a twelve-oh-two.”
Twelve-oh-two. A warning that the lunar module’s main computer was overloaded. So much was happening and so quickly, so many performance signals were being generated, that the computer could not absorb them all.
In Mission Control everyone sensed an abort.
All eyes were on Steve Bales.
He stared at his console. Coded numbers told him instantly what was going wrong. He needed confirmation that his identification of the problem was correct and safe for Armstrong and Aldrin.
Bales called Garman in the back room. “It’s executive overflow,” Garman assured him. “If it does not occur again, we’re fine.”
Bales agreed, and he judged Eagle’s main computer was doing its job.
He keyed his mike. “GO!” he shouted.