ELI5: Explain Like I'm 5

Aerocapture

Aerocapture is like catching a ball. But instead of using your hands, you use the air around you. It's the same thing spacecraft use when they come down to land on a planet. They use the planet's atmosphere to slow down and stop.

Before a spacecraft can land on a planet, it has to slow down a lot. That's because planets have gravity, which pulls things towards them. If a spacecraft landed at its full speed, it would crash and break into pieces.

So instead of landing all at once, spacecraft go through a few steps. The first step is called aerobreaking. This is where the spacecraft flies through the planet's atmosphere and the air helps slow it down.

But sometimes, even aerobreaking isn't enough. Sometimes, the spacecraft has to slow down to a stop in a short amount of time. That's when aerocapture comes in.

Aerocapture is when the spacecraft comes through the planet's atmosphere and uses the air to slow down. The spacecraft dips into the planet's atmosphere at just the right angle and speed so that the air helps slow it down. The spacecraft can then use its engines to tweak its position and speed to prepare for a landing.

It's kind of like catching a ball. When you catch a ball, you move your hands to the right spot and catch it. You use the ball's speed and direction to help you catch it. Aerocapture is the same way. The spacecraft uses the planet's atmosphere like your hands use the ball's speed to help slow down and come in for a landing.