ELI5: Explain Like I'm 5

Apollo pre-launch abort modes

Imagine you are going on a trip and your mom is getting you ready. Before you leave, she makes a checklist of things like snacks, water, and sunscreen that you should have with you. This is called a pre-flight checklist.

Just like how you have a checklist before going on a trip, NASA also had a checklist called the pre-launch checklist before sending astronauts to space. One of the things on this checklist was to make sure the rocket, called the Apollo, was working properly. If it wasn't working properly and the astronauts could get hurt, NASA had different ways to stop the launch. These ways are called abort modes.

There were different abort modes for different situations. For example, if something isn't working right while the Apollo is still on the ground, it can't launch. So, NASA has an abort mode called the pad abort. This means the astronauts would quickly get out of the rocket and go to a safe place if something went wrong before the launch.

If something went wrong during the launch or shortly after, there were different modes called the abort modes. Sometimes the rocket could turn back and land on the ground instead of going to space. Other times, the astronauts could escape in a special small rocket that was on top of the Apollo.

So, just like how your mom has a checklist before you go on a trip, NASA had a checklist called the pre-launch checklist, which included different abort modes for different situations. These modes were there to keep the astronauts safe in case something went wrong during the launch.