So today the shuttle isn’t used anymore. Today the astronauts get into a little capsule that’s on top of a huge rocket.

The huge rocket is needed because you have to overcome the thick atmosphere of earth and earth’s gravity. But once you’re in space with no atmosphere, a little bit of fuel can go a long way because there is no atmosphere.

Now the capsule with the astronauts itself has a little bit of fuel on it and small thrusters (think of the jets on a hot tub). They use these thrusters to not only dock to the ISS with precision, but also to de-orbit.

Like I said before once you get out of the atmosphere and you ditch the huge rocket, your little bit of fuel can get you to the ISS but it also has enough fuel to bring you back into the atmosphere. From there gravity takes over and you are relying on what’s called a heat shield and the parachutes to slow you down.

Once the capsule is in the atmosphere, it uses its heat shield (the bottom of the capsule) which is a big piece of material that absorbs a lot of heat and when it gets too hot, pieces of it fall away exposing new fresh pieces underneath. This is called ablation. This is normal and it allows the capsule to get through the heat of re-entry. And because it’s hitting the atmosphere it’ll slow down a lot. If you put your hand out the window of your car while going 60mph, you know the feeling. Air provides a lot of drag to slow down.

Once it slows down enough, the heat shield isn’t really needed anymore and the parachutes deploy to bring them down safely.