by Jay Barbree
They were in their seats with their Apollo command and service modules docked with their lunar lander moving backward some 300 miles above the moon—a moon they would not see again until they turned around following the planned 6 minute, 2 second burn needed to brake their speed from some 5,000 miles to 3,000 miles per hour where lunar gravity would secure them in an orbit 61 by 169.2 miles.
The crucial rocket firing was set for 7 minutes and 45 seconds into their farside pass and Neil and Mike and Buzz double-checked their settings—once, then again, and then a third time to make sure they did it right the first time. It had to be perfect. Just one digit in the computer out of place could send them into a lunar mountain or turn them and send them into an orbit around the sun.
But that wasn’t going to happen. Neil and Mike and Buzz were sure of that. When they reached the mark, the three crew members felt the gentle ignition and heard the rumble of the SPS propulsion system burning. The numbers told them the rocket had fired and was running—burning smoothly and evenly for what seemed to Neil and Mike and Buzz an eternity. They stared into the blackness unable to see the moon—only sensing it—as their SPS propulsion system slowed their speed, moving them to within 61 miles of its surface. Their only worry was would the rocket burn too long, crashing them into the moon that was ever so near, and for 6 minutes and 2 seconds they rode Apollo 11 to its slower speed. When it was over, finally over, it was a splendid and epochal moment: 75 hours and 55 minutes after ridding itself of its shackles on the launchpad, Apollo 11 locked itself in lunar orbit.
No one on Earth knew that this had happened. In Mission Control this was a time of cliff-hanging suspense, a time to count the minutes and seconds that had to pass before Apollo 11 emerged from the lunar farside to where it would hopefully signal success.
But on Apollo 11 the celebration was already under way. The numbers were perfect. They had turned their spacecraft around and were looking down at the moon excitedly pointing out one spectacular feature after another and when they came around the lunar limb and Mission Control could hear them at the instant they should have, Earth celebrated.
“Apollo 11 is getting its first view of the landing approach,” Neil told Mission Control, recalling the pictures and maps brought back by Apollo 8 and Apollo 10.
On one of the pictures Jim Lovell had taken from Apollo 8’s orbit only miles above the moon was a small lunar mountain. It was in the right spot for Neil and Buzz to ignite their descent stage. Lovell had named it Mount Marilyn. It would be Apollo 11’s landing marker.
“We’re going over Mount Marilyn at the present time,” reported Buzz.
“Roger. Thank you,” acknowledged CapCom, quickly adding, “Jim Lovell is smiling.”
Mission Control filled itself with laughter. Every flight controller knew the small mountain was named for a great wife and mother. Each also knew she had weakened only once—the day she had married Jim Lovell.
Neil’s voice broke through the laughter. “Jim has given us a very good preview of what to look for here,” he told Mission Control. “It looks very much like his pictures.”
* * *
“This time we are going over the Taruntius crater, and the pictures and maps brought back by Apollo 8 and 10 have given us a very good preview of what to look at here. It looks very much like the pictures, but like the difference between watching a real football game and watching it on TV. There’s no substitute for actually being here.”
“Roger. We concur,” CapCom answered. “We surely wish we could see it firsthand.”
“You will,” Neil said. “There’ll be lots more chances.”
* * *
Snug in their lunar orbit, the Apollo 11 astronauts had arrived and it was time to get the lunar module Eagle ready to land on the Sea of Tranquility. Neil and Buzz powered up their lander and moved through their list of checkouts before returning to Columbia for their fourth night.
Midday Sunday, July 20, 1969, Neil and Buzz were back aboard Eagle, and as they began their 13th orbit around the moon, Neil reported to Mike Collins, who was keeping the fires burning on board Columbia, “Eagle’s systems are looking good.”
From the command module Columbia astronaut Mike Collins watches lunar lander Eagle with Neil Armstrong and Buzz Aldrin move away for their landing on the moon’s Sea of Tranquility. (NASA)
“Hello, Eagle,” Mission Control called. “We’re standing by, over.”
“Roger,” Neil reported back. “Eagle is undocked.”
“Roger. How does it look, Neil?” CapCom asked.
“The Eagle has wings,” he told Mission Control, and once again billions watching on television held their collective breath.
From the Eagle, Neil and Buzz followed Mike and Columbia around the moon. (NASA)
NINETEEN
THE LANDING
Columbia came around the moon followed by Eagle, and Mission Control told them, “We’re standing by, over.”
“Houston, this is Columbia. How do you read me?”
“Roger, five by, Mike. How did it go, over?”
“Beautifully.”
“Great. We’re standing by for Eagle.”
“Okay, he’s right behind me.”
Neil Armstrong and Buzz Aldrin were ready. They stood with their boots against Eagle’s flight deck. They were flying backward with their faces parallel to the silent landscape below. Neil felt very comfortable with the astronaut in the CapCom chair in Mission Control. His name was Charlie Duke and he had already spotted a problem. Eagle’s high-gain antenna needed tuning and Neil got right on it. But more important if a serious problem popped up, Neil knew Charlie would catch it right away.
Eagle in lunar orbit getting set to land on the moon. (NASA)
“Houston, Eagle. How do you read?”
“Five by, Eagle,” Charlie quickly responded. “We’re standing by for your burn report, over.”
“Roger, the burn was on time,” Buzz told him. “It was perfect,” he added as he began reading Charlie the numbers while Neil and flight controllers fussed with Eagle’s high-gain antenna.
They spent the next several minutes reporting and confirming positions, measurements, and altitudes with Mission Control and then a final check with all involved, and CapCom told them, “Eagle, Houston, if you read, you’re Go for powered descent.”
Neil and Buzz hadn’t read. Neil was still yawing Eagle’s high-gain antenna trying to get it tuned just right, but Mike Collins above them in Columbia heard clearly. “Eagle,” Mike called, “This is Columbia. They just gave you a Go for powered descent.”
Neil and Buzz glanced at each other.
Powered descent. They were cleared to land.
They shot each other a wide grin and Neil calmly acknowledged Charlie with a “Roger.”
* * *
Inside Mission Control’s terraced rows of consoles and monitors manned by a small army of tense flight controllers sat a man who gave the finger to the long hair and outlandish garb that defined the 1960s.
With an outdated crew cut adding starkness to his features, Gene Kranz seemed strangely out of place. Yet he was the mission’s final authority, the flight director whose sweeping powers would decide the what, when, and where of the first-ever descent to the moon’s surface. Now, with Neil and Buzz dropping silently toward lunar dust and craters, no one called him by name. He only answered to “Flight.”
He leaned into his communications panel and switched from the flight director’s network to a flight-controllers’-only loop and told his team, “Hey, gang, we’re really going to land on the moon today. No bullshit. We’re really gonna do it.”
Heads and bodies turned with smiles and thumbs-up to meet his words, and he switched back to the flight director’s network so that the tense, nail-biting VIPs and families in the viewing rooms could again hear. Kranz, like the crew aboard Eagle, a former fighter pilot, appeared calm, but it was a front. Kranz’s stomach was knotted. His heart thumped hard and loud, and when he lifted his rig
ht hand from the cover of the moon landing flight plan, he left behind a wet, perfect image of five perspiration-soaked fingers.
* * *
But more important than any other this day were the fateful words had been relayed across space: “Eagle, you are Go to ignite your descent engine.” Neil locked his eyes on the glowing numbers displayed before him. He and Buzz were almost at the invisible junction of height, speed, range, and time when everything would come together. When the instruments would tell them they were 192 miles from their projected landing target, and precisely 50,174 radar-measured feet above the long shadows of the moon, they would unleash decelerating thrust and begin braking their speed for the touchdown.
Bright green digits changed constantly, the numbers flashing by in a breathless blur.
Then this was it. PDI. Powered Descent Initiate. On Earth, radio listeners and television viewers held their breath. Fingernails dug into palms.
Neil Armstrong preparing to land Eagle on the moon. (NASA)
Neil and Buzz braced themselves for ignition. At ten percent power there was no sudden hard smash of energy as Eagle’s descent rocket was brought to life with a caress. Gently the ship descended through the black sky.
The Eagle’s electronic brain monitored the deceleration, measured the loss of velocity, judged height, and confirmed the angle of descent. The invisible hand of the computer then began to add power. Gradually Eagle’s descent engine increased to full power.
Flame gushed beneath them—glowing, gleaming plasma in a shock wave buoying in a vacuum and Eagle rocked from side to side. The lunar module’s computer was so sensitive, alert, and instantly responsive, it fired control thrusters gently to hold the craft steady. Hollow thuds, distant subdued bangs, could be heard within the four-legged landing craft as small thrusters performed the ultimate balancing act.
Gravity pulled at Eagle far more gently than it would have on Earth as inside Neil and Buzz, who had been weightless, free from the weight of the heavy pressure suits and boots, were once again growing in weight. Their arms sagged. Legs settled within their suits. Their feet pressed downward in their boots as they yielded to their down-rushing speed.
Neil realized his eyes were tired, but he was alert with anticipation, immersed in the reality of the incredible adventure now before him, and he saw Buzz grinning like a kid.
Good Lord, they were going to land on the moon!
Fuel pumped through the lines under full throttle. Flame spewed far ahead and beneath them. The Eagle was in full fury now, blasting away weight and mass, slowing, slowing.
Headsets crackled at four minutes as Charlie Duke incredibly calm and professional called out, “You are Go. You are Go to continued powered descent. You are Go to continue powered descent.”
“Roger.”
But all was not well.
* * *
Back on Earth, Mission Control was thick with tension.
The highly trained flight controllers were focused on their monitors, tracking the curving line of the Eagle’s landing descent. They were waiting for the vertical metal probe that extended from the landing legs of the ship to touch the moon’s surface and signal a successful landing.
Those manning the front row of consoles were in what was known as the “trench.” This was where final decisions were made, where ultimate responsibility lurked, where Deke Slayton placed his attention.
Deke had confidence in all those who worked in the supercharged atmosphere of the trench, but he was especially keen about a 26-year-old computer hotshot named Steve Bales. Like many in the control center he was young, but he was a seasoned veteran.
No one called him by his name. With a mission under way, he became GUIDO, the acronym for guidance officer. To the old-timers in the space business, Bales was pure genius. They referred to him sometimes as the “Whiz Kid.”
Bales had been early for his shift, excited, filled with anticipation and wonder at what was coming. This was the most important, demanding, and exciting day of his life, and that sobering thought stayed with him as he took his seat at the guidance officer’s console and nervously began twisting a lock of his hair.
Bales made a mental run through the list of possible signals that could sound danger alarms at any point in the epochal descent of the Eagle. And he knew that 24-year-old Jack Garman, in the back room, was running through the same mental checklist. Both were experts on the lunar lander’s computers located deep within the bowels of Eagle.
These computer systems were essential to measuring all the electronic and mechanical forces and factors that would determine the success of Neil’s and Buzz’s touchdown on the moon. A landing soft enough to safeguard the health of the crew and maintain the structural integrity of the bug-eyed lander demanded a complex monitoring system. Changes in speed; rates of deceleration; shifting centers of gravity, weight, and balance; and engine thrust were all factors that were too sophisticated for the human mind to process. Computers—electronic brains—were designed to perform the superfast computations and to ride shotgun on everything that happened aboard the lunar module.
The computers aboard also contained sensitive electronic watchdogs. Alarm systems to detect imbalance, misalignment, and deviation from the exquisitely created flight plan. Only Bales and Garman were familiar with each of those alarms and what they meant. They were the only two people in that vast control system equipped to interpret any alarm emergencies aboard Eagle.
Everything they monitored within the landing craft was green and Go. The tension was there, but everyone was feeling pretty good about the descent.
Then, it all went out the window.
Suddenly Eagle’s computers shrilled madly.
Alarm!
Emergency signals flashed within Neil’s and Buzz’s landing craft and one-and-a-half seconds later on consoles in Mission Control. No one expected a cry for help. Not now.
Eagle’s descent engine had blazed at partial throttle for 26 seconds. Everything fit within the flight plan. But at 6,000 feet above the moon a yellow light flashed at the two astronauts.
On their way down to the Sea of Tranquility, Earth appeared in Buzz’s window. (NASA)
Buzz had just told CapCom Charlie Duke, “Got the Earth right out our front window,” when Neil quickly asked about the alarm: “Houston, you’re looking at our DELTA-H?”
“That’s affirmative.”
Neil swore under his breath. “Program alarm!”
“It’s looking good to us, over.”
The commander of Eagle came back. “It’s a 1202.”
“1202,” Buzz repeated Neil’s reading.
Neil would have been less distracted by the computer alarms if he had known more about a simulation that had been conducted just a few days before their launch that indicated “executive overload” was not a problem, but even so he found the alarm a distraction.
What Neil relied on was the same conditions relied on by most test pilots—good velocities, good altitude, and the navigation was humming. There were no anomalies other than the computer saying, “Hey, I have a problem.” There was nothing else complaining and his first judgment told him to keep flying, to believe his eyes, and he did, while Bales continued trying to prove the alarm was a condition of executive overload.
Bales and Garman knew for sure the warning was saying the computer was overloaded. So much was happening, so many performance signals were being generated that the computer could not absorb them all. What the two computer whiz kids didn’t know was that Buzz Aldrin had decided to run both—not just one—but both of the systems Pings (primary guidance) and Ags (abort guidance) at the same time overloading the computer even more. The computer geniuses at MIT hadn’t allowed for that—you can run one but not the other, but Buzz rightly judged both should be running should you need either. Neil, remembering how running both guidance systems at the same time almost sent Apollo 10’s Snoopy crashing into the moon, came back with a demand to settle the whole damn thing, “Give us a reading on the
1202 Program alarm, Houston, right now.”
Steve Bales almost jumped out of his seat. All eyes were on him and he swallowed hard. He knew instantly the numbers he was reading were executive overload. He just didn’t know why but instantly judged, “no harm.” “Go!” he yelled. “Go!”
Surprised, Charlie Duke snapped, too. He didn’t have time to wait. “Roger. We got— We’re Go on that alarm.”
Neil bit down hard. He’d buy that.
Let’s go fly.
* * *
Thirteen hundred feet above the moon’s surface, Eagle began its final descent. Flames gushed downward as the craft slowed. Neil had flown his mission right along the edge of the razor. He and Buzz functioned as one. Now they were doing more than falling moonward. They were so close Neil had to fly the lunar lander. He punched “Proceed” into his keyboard. The computer would handle the immediate descent tasks. Buzz would back up both man and electronic brain so Neil could adapt to flying in a vacuum.
CapCom Charlie Duke, who would later walk and drive a lunar buggy on the moon, was on pins and needles during the landing. Backing up Charlie sitting on his left was famed Apollo 13 commander Jim Lovell and lunar module pilot Fred Haise. (NASA)
A momentary smile crossed his face. Now let us see if those 61 LLTV training flights were worth it, the training he needed to land on the moon. Neil was betting they were. He was hopeful they had given him the skills to get the job done.
He looked through his triangular window and studied the desolate, crater-pocked surface before him. He had made many simulated runs, pored over dozens of photographs taken by Apollo 10 marking the way, landmark by landmark, down to the Sea of Tranquility. He knew their intended landing site as well as he did familiar airfields back home, and he immediately noticed they weren’t where they were supposed to be. Damn!
Eagle had overshot by four miles. A slight navigational error and a faster-than-intended descent speed accounted for their lunar module missing its planned touchdown spot. Neil studied the rugged surface rising toward him and Buzz noted a yawning crater wider than a football field. Eagle was running out of fuel and headed straight for the gaping lunar pit filled with boulders larger than a Purdue jitney.
