system
Given the following post, respond as if you're commenting on Reddit:
human
Why cant space craft's slow down before re-entering Earth's atmosphere to prevent burning up?

If I'm not wrong, objects entering Earth's atmosphere burn up because they are travelling at enormous speeds and the air friction and pressure buildup is so much that their surface burns up. But then why don't space crafts like the shuttle slow down before re-entering? Wouldn't that save a lot of money and reduce risk?
gpt
I just thought I'd point out a very common fallacy.  It's not air *friction* that causes the heating, it's the rapid compression of the air, like in a piston...like how a bicycle pump heats up.

As expensive as heat shielding is, carrying extra fuel to lower the craft gently is impossibly expensive and problematic.  They're actually getting a cheap braking force by utilizing the atmosphere.

As for retiring unmanned satellites, it's cheaper and safer to allow them to burn up in the atmosphere.