Real-time data from the Apollo 11 astronauts, carefully monitored by Mission Control, captures the frantic maneuvers that landed a man on the moon.
Editor's note:This article is part of aSerieReflecting on the Apollo 11 mission, 50 years later.
Two men were about to land on the moon, and mission control in Houston was seething with tension. At the science center, Gerald Schaber, a geologist, had to do something while waiting for the lunar module to land. Scraper had come from northern Arizona, where engineers had distorted the desert with dynamite to make thema crater landscapewhere astronauts could train. Their work only began when Neil Armstrong and Buzz Aldrin left the lunar module and began exploring the slate-colored surface. And the waiting bothered him.
"Our hearts were beating [fast], all of course," Schaber told me recently. "So I figured I might as well take care of hers."
Schaber switched his monitor to the channel showing biomedical data for the astronauts. Armstrong seemed calmer than some of the Mission Control people. The commander's heart was beating at 75 beats per minute, a remarkable rate for someone about to land on the moon. The normal resting heart rate for an adult is between 60 and 100 beats per minute. My heart rate is now at 75 as I write this story, according to a fitness tracker.
Scraper wasn't surprised. Everyone knew Neil Armstrong was one of the best drivers in the country. This was the pilot who ejected from his fighter plane, damaged in the Korean War, with such force that it felt "as if every part of his body had been blown off."squeezedin a space the size of a breadbox.” The astronaut who once managed to erect his capsule in space while spinning wildly, one revolution per second, and his visionturned offof the tip. The lunar commander, who once again ejected from a failed landing simulator in less than three seconds before falling to the ground and dyingdevoured by flames- just a year before he really needs to fly.
Read: The Year Men Walked on the Moon
The stability Schaber had seen didn't last. Armstrong's heart began to race. When the module landed two hours later, his heart rate was 150.
NASA monitored the Apollo 11 crew's heart rate along with other physiological signals from start to finish. Astronauts wore EKG sensors on their chests, which were shaved before launch for maximum grip. At first glance, an EKG is little more than black squiggles scratched across a page. But the lines and curves are vocabulary. Together they tell the stories of the ups and downs of the mission, the harrowing maneuvers and funny banter, the moments that tormented flight surgeons. They are proof that the human heart beats in another world for a short time.
On the morning of July 16, 1969, Apollo 11 astronautswentfrom their quarters at Kennedy Space Center in their space suits, helmets glistening like soap bubbles, and got into a white van that drove about 15 minutes away to the launch pad. The Saturn V rocket waited, a giant beanstalk of modules and engines against the clear Florida sky. An elevator took them 34 floors to the spaceship. The rocket's engines roared to life and 7.5 million pounds of thrust hit the ground. Apollo 11 was on its way.
"We now have a launch heartbeat report from the flight surgeon," a NASA official announced to the public 36 minutes after launch. "Commander Neil Armstrong's heart rate: 110. Command Module Pilot Michael Collins: 99. Lunar Module Pilot Buzz Aldrin: 88."
All three men had previously launched into space. NASA put them through extremely rigorous training, including putting them through a fainting simulator until their bodies learned not to faint. "While you and I would say, 'Oh my God, I'm on a 300-foot rocket filled with liquid hydrogen that could take us to the sky,' to them it's like, 'I'm going to do the work'" , says John Charles, a retired NASA scientist who has worked with astronauts and monitored their health.
Seventeen hours after launch, the Apollo crew prepared for their first sleep in space. Mission Control stayed awake, monitoring the men's vital signs as well as their heartbeatsplunged into the 40s, a sign of deep sleep. Flight surgeons knew the astronauts were awake before they even called. The crew made coffee, ran the module's engines for a few seconds to set course for the moon, and ate salmon salad while Merrilee Rush sang "Angel of the Morning" into a tape recorder. "Hey, do you have a doctor downstairs to monitor your heart rate?" Collins asked Mission Control about breakfast. "I'm trying to walk down here and just out of curiosity, I'm wondering if it gets my heart rate up."
"We see your heart beating," replied Charlie Duke, the spacecraft's communicator in Houston. "Mike, we're seeing about 96 heartbeats now."
Two days later, Mission Control could see nothing. The command module was circling on the far side of the moon, out of range of radio communications. During this period of silence, the module slowed and fell into orbit around the moon before turning back.At the momentWhen the men succumbed to otherworldly gravity, Armstrong's heart rate was 106, Aldrin's was 70, and Collins was 66.
The crew would orbit the moona dozen more timesbefore one spaceship became two. Collins stayed in the Columbia module, his living quarters, while Armstrong and Aldrin climbed into the Eagle module and drove it to the ground. As they descended, the gentle pull of the moon's gravity greeted them. "His arms gave out. Their legs tucked into their suits. Her feet pressed into her boots as they yielded to her downward speed.he wroteJay Barbree, a longtime space journalist and Armstrong confidant, inAn Astronaut Biography, died in 2012.
Read: What does the moon landing mean for the future?
Then an alarm sounded; The Eagle's computers were overloaded with signals. Mission Control told Armstrong to ignore it and continue. Armstrong could see enough rough terrain through the window to know they were four miles over target. They needed a smooth, flat place to land, and Eagle was now heading for a boulder-filled crater. It was time to turn off autopilot. Armstrong took control of Eagle and manually steered the module away from the crater. The module was still in the air when the low fuel light started flashing. (Another propulsion system would take astronauts back to the moon.)
Armstrong later said he wasn't worried about fuel. They were close enough that the moon's gentle gravity, one-sixth that of Earth, would lower them safely with the engine off. But the descent must have been a bit of adrenaline to get the moon commander's heart rate up to 150. Armstrong's pulse began to increase after he disengaged the autopilot and took control in his gloved fist. The fate of the mission was literally in their hands. Tens of thousands of engineers helped him get this far, but the last part was up to him. That kind of responsibility would make anyone's pulse quicken.
"OK. I am now leaving the LM.
Armstrong stood outside the module, hovering between a rung of the ladder and history. As your foot pressed the moon's regolith, your heartSmoothieat 125 beats per minute.
The two astronauts skipped the surface, setting up science experiments and collecting rocks for geologists like Gerald Schaber, who was tracking the men's movements in the grainy black-and-white footage at Mission Control at the time. The moon made the movement so easy that Armstrong and Aldrin didn't stop to rest. "At no time during the exercise was there heavy breathing," according to NASAmission report. "Most of the time, the astronauts' heart rates were lower than expected -- in some cases lower than those of the mission controllers watching."
But as the astronauts neared the end of their excursion, Armstrong's heart rate shot up to 160. He loaded crates full of rocks into the module using a pulley system developed by NASA, and it took some effort. Armstrong tied each box to a loop of cloth, then pulled hand by hand until the load was full.jumped to the top of the spaceship, where Aldrin was waiting. "Neil, this is Houston," Mission Control said earlierQuestionshim for an update on his life support system stats. They didn't really need them; They just wanted Armstrong to slow down.
On the Eagle, Armstrong and Aldrin were having trouble sleeping, and Mission Control noticed it long after they said good night. armstrong heart ratesubmergedonly occasionally in the '50s before returning, suggesting he simply dozed off. The module, he later said, was loud, cold and too bright even with the shutters closed. He was connected to the events of the day. Just as he's getting comfortable, Armstrongrealizedsomething shone right in his eyes, "like a lamp." It turned out to be Earth shining through the module's telescope.
The following day, Eagle was put back into orbit and synchronized with Columbia for the return to Earth. Two days from home, a flight surgeon saw something that made him jump out of his chair. Aldrin's heartbeat hadrisen, incredibly, at 247 beats per minute. "The surgeon is dying," Duke told the team, laughing. It was just a mistake; the sticky paste under Aldrin's sensorsdried out,according to the mission report. "Well, I can assure you my heart is still working," Aldrin said to Duke.
Die Apollo-11-Missiontranscriptsare peppered with jokes and light banter between the crew and Mission Control, even during stressful times. But this one looked particularly excited. The hardest parts were over, and the men were almost certainly home. The sensors had done their job. They captured the fear and nervousness, the frantic maneuvers and relaxed pauses, calling them home when sleeping astronauts couldn't. Soon everyone could finally be quiet.