Hey zosia66, you question doesn’t make sense to me, so I’m wondering if maybe what you actually meant was “why is the pressure outside the atmosphere greater and within the atmosphere?”
So I am going to answer that question.
The pressure outside the atmosphere isn’t greater, but I think I know where your confusion has come from. How came something explode in space because of the pressure? Well. The pressure is on the inside of the satellite and because there is no air in space, all the pressure on the inside is pushing really hard to get out, so if the structure isn’t strong enough, it will explode.
I hope that gives you what you were after, if it doesn’t have a go and I’ll do my best to answer it.