… 5 … 4 … 3 … 2 … 1 … and liftoff!

Ever since I was a kid, I’ve loved rockets and everything about flying to space. So the sound of the countdown leading up to a rocket launch is music to my ears. Of course, the sound that follows the countdown is anything but musical because rockets are really loud … but they’re also beautiful. And they’re marvelous machines that will soon be playing an increasingly crucial role in our day-to-day lives as we begin the journey towards becoming a truly space-faring species. And to top it all of, they’re machines powered by math (and, of course, a bunch of physics and fuel).

What's the math that powers rockets? How does it help us get them to space? And how do we use that math to put a satellite or person in orbit around the Earth? Let's find out.

## The Mathematics of Getting to Space

When people think about going to space, they usually think about going up. And that’s certainly true, but it’s only part of the story. It’s sort of hard to define exactly where the atmosphere ends and outer space begins (since the atmosphere gradually falls off as you go up in altitude), but one popular choice is the so-called “Karman line” at a height of 100 km (or around 62 miles) above sea level. A lot of people are surprised to find that space begins only 100 km up … since that’s really not that far. But the problem with getting there is that it’s “uphill” the whole way, which means you have to fight gravity the whole way.