Leadership Reflections from Apollo: #WorkingOutLoud

As well as the main chapters for the Guidebook, there are some shorter topics that will be covered in breakout boxes. Today i am sharing three of these as part of #WorkingOutLoud.

Reflection: Orbit

If you are a mathematician, or orbital mechanic, please feel free to skip this section. But for the rest of us amateurs, consider falling down. Or rather, falling off.

There was one thing i learnt whilst researching this book that really stuck in my head: that going ‘into orbit’ is not about throwing something up into the air and hoping that it stays there, but more about throwing it in a curve, off the edge, until it perpetually falls.

There are two forces at play: the energy put into lobbing the spacecraft up, and the gravity that tries to pull it down again. If you throw a ball on earth, it goes in an arc: you put energy into the system, and the ball goes up, but over time and distance, gravity pulls it back down. Literally, ‘what goes up, must come down’ [1].

Although that is not always true: if you put enough energy into it, it could break away from the Earth’s gravity entirely, and keep going forever. Or until it hits a passing spaceship, alien, or interplanetary greenhouse. It takes a lot of energy, but then space travel is mainly about energy, and escaping our planet’s gravity is a big part of it.

The diagram shows the three states that i found most useful to understand this: [THREE] launch the spaceship with not enough energy, and you get a ballistic lob (which is pretty much how an intercontinental ballistic missile works). What goes up, travels in an arc, and then comes down, with a bang. This is good if you are trying to hit something, but bad if you want to get into orbit.

[One] Use more energy, and the spaceship goes up, escapes gravity, and goes forever. But use just the right amount, and it goes up, in an arc, and starts to fall down, but it’s gone ‘over the edge’ [TWO].

It remains in balance: it is, in effect, endlessly falling. In my understanding, it misses the edge of the planet, so falls, but as it travels around the planet, so gravity goes with it, pulling it equally at any point.

Once in orbit, it takes relatively little energy to maintain it, which probably speaks to the stability of many systems.

Leadership Reflection: it may require a great deal of brute force to achieve an end, but the devil is in the detail: understanding the complex forces and interplay of forces at work, and fine tuning with a nudge in the right direction, is probably the route to success.

[1] And yes, i know there is friction, and energy leaking out as noise and heat, but let’s keep it simple.

Reflection: Ullage

As everyone knows from their schooldays understanding of rockets, they come in stages: during launch, each successive stage is used up and separated. When this separation occurs, it’s not as smooth as you may think: when one rocket stops burning, the craft brakes, and can momentarily become weightless, then the next stage engine kicks in, and off you go again.

But in the complex world of fuel, this is an issue: the weightlessness means that the fuel may not be at the bottom of the tank, where you need it. It sloshes up to the top, where it does no good at all. And as with most things rocketry, this is very bad news.

So as well as the giant Saturn V engines, and the ascent and descent SR1 engines, there were a whole series of ullage rockets, with a small but important function: they started to fire one fifth of a second before the stage separated, and fired for a total of four seconds, and then were discarded thirty seconds later. They served two purposes: firstly, they forced any gas into the space at the top of the fuel tank, where it belonged, and secondly, they created a slight pressure at the engine inlet.

Saturn V rockets carried at least four of these engines, with 150kg of solid rocket propellant in each, and they served a small but vital function in the success of the mission [1].

Leadership Reflection: small cogs make the whole machine work.

Notes

[1] In Woods (2016)

Reflection: Slowing Down

The inferno of liftoff implies that we are trying to leave the earth, so it seems rather counter intuitive that a great deal of effort was put into preventing the rocket from doing so: the entire weight of the rocket sat on four ‘hold down arms’, which prevented the vehicle from moving during transport, but more importantly, prevented it from taking off when the engines fired.

Effectively the hold down arms acted like four pincers: left to it’s own devices, the rocket could shoot off with an erratic and shocking force, especially if, for example, one engine achieved full thrust before the others. So at launch, all the engines spun up, and once equal thrust was verified, the hold down arms retracted.

But these arms were not the only thing that held the rocket back: there were a series of ‘controlled release mechanisms‘, which are best viewed as a series of tapered rods (attached to the rocket) that had to be pulled through a series of disks with holes in, attached to the launch pad. The rocket could start to move, but the force required to distort the rods and squeeze them through the holes in the disk again would slow down departure, and provide an element of throttling, meaning a somewhat smoother liftoff.

Leadership Reflection: pace and tempo count. It’s easy to assume that momentum is the answer, but not always correct.

Notes

[1] In Woods (2016)