Apollo 11: Off course and low on fuel, heart rate data reveals the tension of the first Moon landing

Updated

As Apollo 11 Commander Neil Armstrong approached an uncharted world, as far from home as any human had ever travelled before, he transmitted vital data back to Earth.

Monitors showed his heartbeat at a steady 110 beats per minute, ridiculously low for someone hurtling in orbit around the Moon.

But the closer the crew got to the Moon, the more problems they encountered.

Alarms they'd never seen before were going off.

Fuel stores were running perilously low.

And as the world tuned in to the final moments of the descent, Armstrong's pulse skyrocketed.

This is the story of the tension inside the first manned landing on the Moon.

When John F. Kennedy stood before the United States Congress in 1961, asking for funds for a mission to the Moon, he set the clock ticking.

Before the close of the decade, Kennedy wanted the boots of US space explorers on the surface of Earth's Moon.

It was a race against time that cost both lives and billions of dollars. And when it finally came time to launch NASA's Apollo 11 mission, it was just months out from JFK's deadline.

But even with all the lessons learnt from previous Apollo missions and the countless hours spent running simulations, there was still one giant unknown and untested phase of this operation: the final descent to the Moon's surface.

Neil Armstrong and Buzz Aldrin were placing their lives in the hands of a computer system designed to land their 15-tonne lunar module, Eagle. It was a complex and dangerous task requiring pinpoint accuracy with no margin for error.

The journey so far

As the astronauts stepped into the lunar module to begin their descent almost 50 years ago, humanity held its breath — from ground control in Houston, to the other side of the world in Australia where teams at the tracking stations at Honeysuckle Creek near Canberra and Parkes in NSW prepared to play their crucial role in this historic moment.

Four days after blasting off from Earth, the Apollo 11 mission enters a communications black spot as it passes across the dark side of the Moon.

The lunar landing craft carrying Armstrong and Aldrin detaches from the Columbia command module, taking the first step in the perilous descent.

Charlie Duke (CAPCOM): Eagle, Houston. We - Houston. We see you on the steerable. Over.

Armstrong: Roger. Eagle's undocked.

Duke: Roger. How does it look, Neil?

Armstrong: The Eagle has wings.

This is one of the final views Armstrong and Aldrin had of the command module with Michael Collins still inside, before firing up the thrusters and descending to an orbit around 15 kilometres from the surface.

Aldrin: "Okay. Sequence camera coming on."

As Buzz Aldrin flicks on the 16mm camera pointed out his window, the astronauts prepare themselves for powered descent — the final and most dangerous phase of the landing sequence.

This phase had never been attempted outside a simulator. Aldrin and Armstrong were in the hands of what today looks like a rudimentary system, but one that was designed and coded by revolutionary minds.

Aldrin: Ignition. 10 per cent

Armstrong: Just about on time.

Aldrin: ...light is on. 24, 25, 26, Throttle up. Looks good!

Three minutes into the powered descent, the first sign that things aren't going entirely to plan appears.

Armstrong: Our position checks down range show us to be a little long.

Duke: Roger. Copy.

By measuring the time it took to travel between Boot Hill mountain and Crater Maskelyne W, Armstrong was able to confirm his earlier suspicions they were off course.

Minutes later, another more critical problem crops up. Shortly after rotating the lunar module to allow the landing radar to lock onto the Moon, an alarm from the guidance computer appears.

In all the hundreds of hours the astronauts spent in the lunar module simulator back on earth neither had ever seen this 1202 alarm.

Armstrong: Program Alarm.

Armstrong: It's a 1202.

Aldrin: 1202.

An alarm from the guidance computer had the potential to cause the mission to be aborted prematurely. No-one was more acutely aware of this than Don Eyles, one of the engineers from MIT who developed the guidance system's software.

"I was holding my breath, being quiet and seeing what would happen next." he told the ABC. "Something was happening in our computer that we had not seen in tests and which we did not understand and that was very disconcerting."

Thirty seconds passed, an eternity by NASA's standards, before the astronauts received a response.

Armstrong: Give us a reading on the 1202 Program Alarm.

Duke: Roger. We got you... We're Go on that alarm.

Don Eyles knew what the alarms meant. They were the computer's way of saying it was trying to do too much at once. What he, along with NASA and the astronauts, didn't know was why it was happening now. For Eyles, it was a critical unknown.

"If it had been up to me, I probably would have done an abort," he said.

But this close to the surface and with no sign of any system malfunction, NASA decides to press on.

In the dying minutes of the landing, Armstrong flips on p64, the program which would move the lunar module to an upright position and guide them to an area above their final landing site.

But as he does another new alarm lights up.

Aldrin: Program Alarm. 1201.

Armstrong: 1201.

Duke: Roger. 1201 alarm. We're Go. Same type. We're Go.



Seconds later there was another 1202 alarm.

And another, 16 seconds later.

Distracted by the alarms and concerned about whether the mission was going to be aborted, it wasn't until 450 metres from the surface, that Armstrong took his first good look out his window to assess the landing site.

What he saw was worrying. As anticipated they'd overshot the landing site by six kilometres and the guidance system was lowering them down near a huge crater surrounded by a sea of boulders

Armstrong: Pretty rocky area.

Aldrin: 600 feet, down at 19.

To avoid the boulders, Armstrong takes partial control over the lunar module. He slows the descent and sweeps over the boulder field.

The manoeuvre costs the module an extra 240 kilograms of an already depleted fuel supply. They needed a new landing site and they needed it fast.

Back in Houston, a silence descends over mission control. The only exception: critical fuel read-outs.

Duke: I think we better be quiet, FLIGHT.

Gene Kranz (Flight director): Rog. Okay the only call outs from now on will be fuel.

Around 30 metres from the ground, the module's fuel light illuminates. They now had just 94 seconds to either land or abort the mission.

As Aldrin calls out height and speed data and NASA relays the fuel levels, Armstrong's heart starts racing.

Watch as the tense final seconds of the Apollo 11 Moon landing unfold.

Footage courtesy of NASA

The team at mission control in Houston weren't the only ones breathing a sigh of relief. At the MIT Instrumentation Laboratory in Cambridge, Massachusetts, Don Eyles and his colleagues also took a moment to reflect on what they'd helped achieve.

Eyles, now aged 75, was a mathematician by training who only learned computer coding when he joined the MIT team in 1966. And it was the 2,000 lines of code that he wrote which directed the Apollo Guidance Computer to land the lunar module.

The label he gave the crucial landing sequence — "BURN_BABY_BURN" — is now part of computer folklore.

"It was an amazing experience, however many times you've simulated and tried to think of everything that could possibly happen, it's still quite a thrill when it actually works, so it was a sense of great technical accomplishment on our behalf," Eyles said.

It's an accomplishment that still stands the test of time, said Flinders University space historian Dr Alice Gorman.

When you combine the inherently volatile nature of rocket systems and a host of componentry and dependencies which were put under all kinds of extreme physical stresses, what was achieved 50 years ago was a minor miracle.

"It demonstrates just what you can do with simple, often hand, computations and technology [and] to us now, it looks all the more impressive."

But, of course, the job was not done. Within seconds of touching down in the Sea of Tranquillity, Armstrong, the consummate professional, was back to work preparing the lunar module to take off again in the event of an emergency.

"Okay. Let's get on with it," you can hear Armstrong saying to his counterpart from the onboard recording.

The astronauts spent the next few hours inside the module acclimatising to the 1/6th gravity and readying themselves and their equipment for the historic first steps on the Moon.

Australia's historic role in bringing the landing to the world

As they did that, the NASA-run tracking station at Honeysuckle Creek began receiving their first transmissions from the Moon.

The 26-metre dish was one of only three such stations placed around the world to allow NASA a constant stream of communication and data from the astronauts.

Because these transmissions between the Moon and Earth required a line of sight, it meant when it came time for Armstrong to step down the ladder of the lunar module, Honeysuckle Creek was ideally placed to receive and relay the pictures being sent back to Earth.

And it was the job of then 36-year-old deputy station director Mike Dinn and his colleagues to make sure that happened without a hitch.

A Yorkshireman who studied electrical engineering, Dinn arrived in Australia in 1960 to work with the Royal Australian Air Force before moving to tracking spacecraft at, first, Tidbinbilla and later, Honeysuckle Creek.

The now famous images being beamed out by Dinn's small team were viewed by an estimated 650 million people — almost a fifth of the world's population at the time.

But even with the world's eyes on their work and knowing full well just how many things could go wrong, Dinn said his team was so well drilled that he wasn't really feeling the pressure.

"We'd done a great deal of planning, training, simulations and what ifs," he said. "Not only did we have Plan A, we had Plan B, Plan C, Plan D and Plan E."

"I was confident the team was capable of providing any support needed, no matter what happened."

If you watch closely in the original broadcasts, you can see the moment NASA makes the decision to switch from the much darker pictures being relayed from the Goldstone station in California's Mojave Desert to Honeysuckle's images — just as Armstrong prepares to take his first step on the Moon.

Viewers around the world watched the images coming from Honeysuckle for nine minutes before the Moon came into view of the larger, 64-metre dish in Parkes. With a much clearer picture coming from Parkes, NASA switched to its images for the remainder of the broadcast.

The Australian involvement in helping to track the Apollo 11 mission and maintain communications, should not be passed off as merely a "bit part", according to Flinders University space historian Dr Alice Gorman.

Australia, she said, had been collaborating with the US space program since the 1958 launch of Vanguard 1, a grapefruit-sized satellite that was the fourth one blasted into space and which is still orbiting the earth 60 years later.

"It [was] the culmination of decades of Australian experience in tracking all kinds of missions and of course building that strong relationship with the US," she said. "People have kind of forgotten that Australia was once a serious space player before the modern era."

The Moon landing (and the successful return to Earth, we should add) was in many ways a defining moment, not only for those involved in the Apollo program but for those watching at home.

It inspired a generation, shifted the boundaries of what was thought possible in science and accelerated the development of technology we've since come to take for granted.

In the decades since the Moon landing, not only have we gone deeper into space landing rovers on Mars, sent probes via Jupiter and Saturn and into interstellar space, but we've also looked back from space to study our own planet in incredible detail.

Credits

Reporting and research: Mark Doman and Stephen Hutcheon

Design: Alex Palmer

Development: Ri Liu and Nathanael Scott

Notes about this story:

The audio transcripts and context surrounding the lunar module descent was based on the incredibly detailed account of the mission in NASA’s Apollo 11 Lunar Surface journal.





Topics: space-exploration, astronomy-space, science-and-technology, spacecraft, the-moon, event, moon-landing, canberra-2600, act, australia, parkes-2870, nsw, united-states

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