when coming back from space, why do astronauts don’t just use a parachute all the way down?

Question

when coming back from space, why do astronauts don’t just use a parachute all the way down?

In: Engineering

Answer 1

If they were just going straight up and falling back down, they absolutely could just use a parachute.

The problem is that they are moving very fast sideways; like 20x the speed of a normal passenger jet. Fast enough that when they hit the atmosphere, it ionizes the air. It’s hot enough to melt practically any parachute.

So instead, most spacecraft use a heat shield and simply the spacecraft’s body to slow down most of the way. It’s very effective for 90% of the slowing down; slow enough deceleration that it doesn’t melt anything or put too high of loads on the spacecraft and astronauts. Then they’ll deploy parachutes for the rest of the way.