The different stages of a rocket
And how they might come in handy.
In the past, we’ve gotten into rockets—how they fly, how far they can go, and how they get home safely. To accomplish all of these things, that come together to enable space exploration, rockets must have a variety of different functions. Every piece of the rocket is used to serve these functions, but which part does what? And why is it even there in the first place? Isn’t a rocket just a big match? To be honest I still can’t decide on that last one. Nonetheless, today we’ll get into the typical build-up of a rocket so we can answer some of these questions, just so you’re prepared next time you get asked to go to space.
Rockets all look something like this: [1]
Some may be taller, some may be shorter, but all rockets that intend to get big things into space need to have pretty much the same structure. We explore the physics behind why this is in a previous newsletter. The large pieces of the rocket are called “stages”. As it ascends, the rocket leaves these stages behind when they stop being helpful. Once a stage serves its purpose, it becomes dead-weight and must be released so the rocket can continue to move forward uninhibited.
Most low orbit rockets have 2 stages and payload. These are usually broken apart like this: [2]
The first stage is effectively just a massive gas tank with engines on the bottom. The only purpose it serves is to give the vehicle the initial push it needs into orbit. However, as large as this is, it doesn’t have enough fuel to get you all the way there. Thankfully, though, by the time you detach it, it’s done most of the work. Throughout the history of space flight, these stages were designed to tumble back down to Earth and land in the ocean. This uncontrolled reentry caused significant damage and meant that they could really only be used one time. All this changed when Elon Musk and SpaceX got into the game. Now, these stages (typically called “Boosters”) can land themselves on boats or landing pads with next to no damage. With what seems like just some more fuel and a new paint job they’re as good as new.
But what about the rest of the rocket? The parts that don’t fall back to Earth? Enter stage 2. The second stage typically has a more complex engine, allowing for better maneuverability and controlled acceleration. This engine is optimized for flying in a vacuum, so it’s perfect to turn on once you get close to space.
This stage has the required fuel to take the payload into its intended orbit. Whether its final destination is around the equator, over the poles, 300 miles above the Earth, or even deeper in space, this second stage can take you there. Finally, once the last leg of the journey is complete, the stage doors open and release the payload (satellite, telescope, etc.) into the night sky.
To ensure the payload has a safe area to operate, the second stage will use some of its remaining fuel to nudge itself back towards Earth. It will reenter the atmosphere, partially burn up, and the rest will fall into the ocean—away from any people or things that could be harmed by this little manmade meteor.
At a high level, that’s pretty much it! Some rockets have more stages, to go longer distances (the rocket that took astronauts to the moon had 3), and some have less. All of them, however, were designed to meet the range requirements of the mission. So take this information the next time you go to space and remember, always sit at the front of the rocket—unless you want to fall back to Earth when you run out of gas.
Thank you as always for reading It’s Not Rocket Science, see you next week!
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Never could understand how that all worked. Thanks for the tutorial and the visuals!