Stan Draws Spaceships 1: Expendable Launch Vehicles


Hello. My name is Stan, and
I like to draw spaceships. I’m making these videos to teach
people about the ideas and engineering behind space travel, and also to learn
more about those things in the process. For the first few videos in this series, I’m going totalk about the different
kinds of spaceships there are. They come in a lot of
varieties and functions, but to start with let’s look at launchers. A launcher is basically any
machine that gets you from here – below the Earth’s atmosphere at 0 velocity, to here – above the Earth’s atmosphere,
going at least 25 times the speed of sound. There are a lot of launcher
varieties – real and speculative, but I’m going to reduce them
to three major categories, and in this video focus
on the variety of rockets known as expendable launch vehicles. All rockets currently operating
today are expendable. They lift off, burning kerosene, or hydrogen or methane
mixed with liquid oxygen, and carry a teeny-tiny payload –
roughly 2% of their mass – on top. They shed mass as they go by dropping
heavy engines and fuel tanks and lighting a new set of smaller engines
running off of smaller fuel tanks, and repeat this as many times as is needed until that little bit at
the top is above the air, and going sideways really fast. Why do we throw away all
this expensive hardware? The main reason is that trying to recover
this hardware is really difficult. Adding reusabilty to a rocket adds mass, and adding mass means you need more fuel
for the engines to get going fast enough, and that adds mass. And the goal of the launcher is
to get *something* into orbit. Preferably something other
than just the launcher itself, like a satellite, or a capsule
– namely, the payload. Shaving weight and keeping the rocket
strong enough to withstand the aerodynamic and heating forces it will encounter
to recover it is extremely difficult. So far, no one’s figured
out exactly how to do it, but a lot of smart people are trying. There are many varieties
of expendable launchers: Rockets like the Atlas II, a stage-and-a-half design
derived from the Atlas missile; The Delta II, a two-stage liquid
rocket with strap-on solid booters; The Soyuz launch vehicle, two-stage core
with liquid-fueled side mounted boosters; And the Delta IV, with two boost
cores around the sustainer, carrying a second stage. And of course, many others. If you have suggestions for something
you’d like to see in future videos, please leave them in the comments below. In the next video I’m going to talk
about partially reusable launchers, and after that we’ll explore
fully reusable launchers. Thanks for watching Stan Draws Spaceships.