111: Height of Saturn In a rocket in meters
On 16 July 1969, JoAnn Morgan drove into the parking lot at Pad 39a, Cape Canaveral, to oversee the fuelling of the giant Saturn In a rocket. In the darkness of the ocean behind, the spacecraft was bathed in the light of xenon arc lamps and enveloped in clouds of oxygen venting from the fuel tanks
"It was an absolutely majestic sight," says Morgan. "I stood out in the parking lot and watched it for a while because it was just so beautiful."
At 36 floors high, Saturn ranks as one of the greatest technical and engineering achievements of the 20th Century. Its development was led by Wernher von Braun who, even while building V2 rockets for Hitler, dreamed of building a rocket to carry men to the moon.
he was technically competent, "says Jay Honeycutt, a rocket engineer and later senior manager at Nasa," but he had great leadership skills and a great ability to communicate with government officials who funded the projects. "
Fuelled by liquid oxygen and kerosene, the rocket was made up of multiple stages. The lowest part of the rocket ̵
"Gee whizz you think, did that thing really fly," says Honeycutt. "Some hundred meters tall and then that little bitty thing up on the pointy end is all that came back – a pretty remarkable engineering achievement."
The Moon rocket might have been even larger. Nasa's original plan suggested developing a rocket called Nova. Fed with eight F-1 engines, it would carry a larger, single spacecraft capable of landing on the Moon and then returning to Earth
2: Maximum speed of the crawler transporters, in miles per hour
The Saturn Vs were put together in the Vehicle Assembly Building (VAB), and its large structure even has its own weather system. Engineers then had the challenge of getting the rockets to the launch pad, some five or so kilometers away. After an initial suggestion to float the spacecraft on barges, it was decided to build giant tracked vehicles called crawler-transporters
With eight giant tracks – driven by 16 electric motors, powered by two generators – the crawler-carriers are more like ships than vehicles. And, like ships, the drivers are part of a team of operators and engineers who keep the vehicles moving slowly to the launch pad. Very slow
During Apollo, it could take up to 16 hours to deliver the spacecraft a few miles from the VAB to the launchpad
"The crawler has the power to go two miles a hour," says Sam Dove driver . "However, you really do not want to get it, especially with a load on it – the most we ever go is one."
Although the driver is sitting in the cab, the heart of the crawler transporter is control room. "It's really the brain and the nerve center for the operators here," says Dove. "The test conductor sets on the second console from the end and controls everything on the crawler."
During Apollo, it could take up to 16 hours to deliver the spacecraft a few kilometers from the VAB to the launchpad. (19659018)
35,000,000: Saturn V thrust at lift-off in Newtons
The Saturn V is the most powerful rocket ever successfully flown
"I felt like we were on a needle, a very large needle," says Frank Borman, the commander of Apollo 8, the first manned flight to the Moon. "
Apollo 8 ranked as one of the most audacious and risky missions in space history . Alongside Borman in the Apollo command module were Jim Lovell and Bill Anders, who gave the endeavour just 30% chance of success
Most seriously, the rocket began to pogo – creating forces on board that would most likely have killed any crew
The mission was considered such a risk because the previous, unmanned, test of the Saturn V – sometimes known as Apollo 6 – had not gone well. "The test flight that we flew right before [Apollo 8] was pretty much a disaster," says Apollo flight director Gerry Griffin. "Almost everything went wrong."
Most seriously, the rocket began to pogo – creating forces on board that would most likely have killed any crew. "We've also lost some fuel lines," adds Griffin, "and the upper stage engine did not restart."
Over the next eight months, von Braun's rocketry team set about solving all the problems before convincing Nasa management the Saturn
"It was gutsy on the part of the program," says Griffin. "It was also gutsy on the part of those three guys who got there and rode the first ever Saturn V."
5: Saturn In the Upper Stages on the Moon
Just nine minutes after the launch, the Saturn V had already shed his first and second stages, sending them tumbling away towards the Atlantic Ocean. The third stage (rather confusingly known as the S4B), with its single engine, gave the spacecraft enough speed to reach orbit before shutting down.
Then, after one and a half revolutions of the Earth, the crew relit the S4B's engine . In a maneuver known as Trans Lunar Injection, the rocket thrust the spacecraft out of the orbit on a trajectory toward the Moon.
As the missions progressed, and the more stages they crashed, the more data they got back
astronauts shut down the engine for a second time, and with the lunar lander extracted from the casing at the top, the rocket was abandoned. But – because it was traveling at the same speed and in the same direction as the spacecraft – unless the crew changed the trajectory, the spent racket would follow them to the Moon
For the first few Apollo missions, Nasa's solution was to send the S4B into orbit around the Sun. And, today, the S4B stages for Apollo 8, 9, 10 and 11 are still orbiting the Sun. The Apollo 12's upper stage, however, was recaptured by Earth's gravity.
For the remaining missions, Nasa came up with a more imaginative plan. Apollo 12 onwards, including a seismometer that relayed data to Earth. By crashing the S4B stages into the Moon, geologists could trace the resulting tremors through the lunar rock to help determine its geological composition
As the missions progressed, and the more stages they collapsed, the more data they got back.
100: Percentage of cloud cover for the Apollo 12 launch
On 14 November 1969, four months after landing on the Moon, Nasa planned to do it again. On board of Apollo 12: Pete Conrad, Dick Gordon and Alan Bean
There was a few rain showers that day, as a cold front moved across Central Florida but meteorologists gave the go-ahead for launch and the countdown proceeded smoothly.  At 36 seconds after launch, as the Saturn V passed through the clouds, the electrical systems in the command module failed
The switch flicked, the command module came back online
"What the hell was that? "
This was Gerry Griffin's first shift as a lead flight director, overseeing mission control
" They had a master caution and warning panel with lights that said what was wrong and Conrad started reading that, "says Griffin . "The whole panel essentially lit up."
As the rocket continued towards the orbit, Griffin sought a solution. "This young man from a small college in southeastern Oklahoma named John Aaron, who was about 25 I would guess, made a call, he said 'tell him to try SCE to Aux .'"
Griffin had never heard of the switch but asked the Capcom, Gerry Carr, to relay the message to the spacecraft. "Conrad had never heard of the switch, so he said" SCE to Aux what the hell is that? ", But Al Bean knew where the switch was, right in front of him."
The switch flicked, the command module came back online.
When the engineers later analyzed the launch, they discovered that the rocket had generated its own lightning, the exhaust creating a circuit between the charged particles in the clouds and the ground. Fortunately, the lightning did not affect the rocket's separate computer which, throughout the drama, kept the spacecraft on track.
"It was really funny to listen to the crew after that," says Griffin. "
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