> Lowering orbit is not easier than raising orbit, it takes the same delta-v.
Why is this? From a layman's perspective it seems like gravity would be a massive form of help here and therefore lowering orbit should require much less fuel.
Why is this? From a layman's perspective it seems like gravity would be a massive form of help here and therefore lowering orbit should require much less fuel.
When a rocket launches to orbit, it only goes up a little bit, just to get out of the atmosphere, and then spends most of its time/fuel on going sideways to reach orbital velocity. If you watch a rocket launch you can see that the rocket starts to tip over and go sideways soon after leaving the pad. This is also why launching from a plane doesn't help you very much, because going up is the easy part of getting to orbit. A plane can't help you with the hard part of getting to 25,000 km/h sideways.
For an object in orbit to stop missing the Earth as it falls, it must slow down that sideways velocity, and gravity doesn't help with that.
You have to put energy into doing it, but the end result is just as much in balance with gravity as the starting point. So if you want it back where it was, you need to spent the same amount of energy to move it in exactly the same way in the opposite direction.
That's why a lopsided orbit is stable. It wouldn't be if down was easier than up.