Why do rockets have to hit the atmosphere at an angle on reentry to not burn up?

477 viewsOtherPlanetary Science

I remember this from Apollo 13, they had to hit the atmosphere at an angle, if they came in too directly they’d burn up. My stupid layman thought is that I’d want to come in directly because if the atmosphere is making me burn up I’d want to take the directest and shortest route to landing so that there’s less atmosphere to burn me up. Obviously that’s not how it works, why not

In: Planetary Science

8 Answers

Anonymous 0 Comments

If an lander attempted to come in at a steep angle they WILL burn up There is a lot more atmosphere to burn you up at lower altitude than there is at high altitude

It is not that our upper atmosphere is super hot, the heat is from friction between our atmosphere and the lander. When the lander is in low earth orbit they are going 24,840-27,772 km/h or 15,435-17,224 mph

So when the lander starts re-entry it come in contact with the atmosphere and there is a LOT friction this does 2 things

Creates a lot of heat

Slows down the lander

this is super important as you need to slow down alot before you can safely get deeper into the atmosphere

TLDR: it is the speed of the lander that causes the heat not the fact that it is in the upper atmosphere

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