As a kid, I never actually witnessed any of the Apollo launches. I was old enough to see some on TV but I honestly cannot recall ever having seen one. I do, however, recall seeing a photo of Skylab in orbit around the Earth, the photo taken from an approaching Apollo capsule.
What do these things have in common?
The mighty Saturn V.
The mighty Saturn V is one of those things you can't just name and leave it alone. It requires a modifier, a nod of respect. It was never just the Saturn V, is was and must always be mighty, or stunning, or amazing. No other rocket launched has ever been bigger or borne a single larger payload to orbit. Nothing, not ever.
Just looking at the Saturn V is an exercise. If you're close, you have to lean waaaay back. It's over 360 feet high, and when the assembled rocket was rolled into the sunshine only two man-made structures in Florida stood taller: the Miami-Dade Courthouse and the NASA Vehicle Assembly Building.
Fun fact: due to its wide-open nature inside the VAB is, although over 520 feet tall, generally agreed to be only one story high. And in the above image we see the VAB has the capacity to assemble not one but two Saturn V stacks simultaneously. The garage doors are the largest in the world, and the cartoonishly large crawler is one of the largest self-mobile manmade objects in the world, and still the largest that carries its own power.
Clearly the Saturn V and everything about it is a constellation of superlatives. When at full power during launch in the late 60s, a Saturn V generated as much power as the entire peak energy demand of Britain. Not London: Britain.
You can see I'm kind of jazzed by all this. It's just a big, dumb rocket, not especially sophisticated in its design or mission, just throw something big into the sky and tune up the flight on the way. Steady-voiced men in the air and flinty-eyed men with slide rules on the ground will make it all work. And they did. With as blunt a tool as the Saturn V and no more computing power than I currently wield in my Texas Instruments calculator, NASA sent up a whole bunch of moon missions, launched a space station the size of an intercity bus, landed a couple of robot laboratories on Mars, et cetera. Very American: big, dumb, ambitious, immensely powerful, successful.
The mighty Saturn V rode into the skies atop five similarly boggling rocket engines: the Rocketdyne F-1. The F-1 almost didn't come about. Originally part of a project requested by the US Air Force, the project was scrapped when the USAF decided they didn't actually need an engine that big. Considering each engine was good for over 1.5 million pounds of thrust, that's not a hard realization to come to. All five F-1s firing together generate enough thrust to lift, for instance, the US Coast Guard's 240 foot long heavy icebreaker Mackinaw completely out of the water.
But when you want to send humans far away and get them home before they run out of air and water, you need to send them fast. And a lot of thrust is good for that, too.
Modern NASA engineers are digging back into the F-1. They are well and truly impressed with the built-up-from-parts nature of the old F-1 but using modern manufacturing techniques are pretty sure they can reduce the parts count by a factor of 10. Not thousands of parts, but hundreds. And with better materials, better processes and better manufacturing, they're pretty sure they can ramp up the peak thrust to an even higher level, high enough to eclipse even the Russian RD-170. Strictly speaking the RD-170 is "one" engine that generates more thrust than the F-1, but it's four combustion chambers running from a single fuel pump, whereas the F-1 is one huge bell. Seriously huge, the expansion nozzle of the F-1 is over 12 feet across. It was designed, through trial and error, to be reliable, robust, flexible and powerful. The F-1 hit all these goals. There were some spectacular failures during the design process but what finally came out had been progressively tested, improved, and tested again. It was about as good a rocket engine as humanity knew how to make in its day and even now, nearly sixty years after it was first commissioned by the military program that ultimately decided it wasn't needed, comes awfully close to defining the state of the art.
When climbing to heaven, perhaps it's best if we put our feet on steps we know and trust.