Anonymous at Fri, 25 Oct 2024 05:33:58 UTC No. 16448442

>>16448439
I'm confused at your question. It takes energy to move an object up, away from gravity. You gain energy when you move an object down, toward gravity. So you gain energy when you move an object from orbit to the ground.

I don't know that that's what you're asking for because it makes no sense. Are you asking if the energy gained is the same as the energy lost? In a perfect system yes.

Anonymous at Fri, 25 Oct 2024 05:36:29 UTC No. 16448443

>>16448439
It takes more energy to get into orbit, because you are working against gravity. A de-orbit burn just requires the spacecraft to slow down enough to have it's orbit intersect with the surface - it doesn't have to cancel all the speed gained from launch.

Anonymous at Fri, 25 Oct 2024 05:37:27 UTC No. 16448444

>>16448439
It’s more of a question of where it is when it is in orbit. Its trajectory is not finalized. Look beyond like up or down

Anonymous at Fri, 25 Oct 2024 10:19:07 UTC No. 16448686

>>16448439
Less, because you've used 90% of your fuel mass to get to orbit, so you need to decelerate to safe landing speed only 10% of the mass.

Anonymous at Fri, 25 Oct 2024 10:20:42 UTC No. 16448687

>>16448443
If you only decelerate to intersect with the surface, you will not be stationary on landing. You will experience violent inelastic deformation.

Anonymous at Fri, 25 Oct 2024 12:57:55 UTC No. 16448850

>>16448439
assuming the use of conventional chemical propellants in something like Starhip, and not some sort of scifi spaceship which remains basically the same mass at all times, no, like anon said >>16448686.

You've also jettisoned your booster stage so theres even less mass to slow down for landing.

Anonymous at Fri, 25 Oct 2024 13:06:44 UTC No. 16448865

>>16448686
>>16448850
Assuming no mass changes of the craft due to fuel or coolant or anything.

Anonymous at Fri, 25 Oct 2024 13:14:08 UTC No. 16448878

>>16448865
probably about the same then since the change in velocity is the same and you've no atmosphere to aerobrake with, but it might need a bit more to land unless you can perfectly reproduce the take off flight path IE. without extra maneuvering.

Anonymous at Sat, 26 Oct 2024 09:40:12 UTC No. 16450247

>>16448439
easier because your TWR will be higher during the period where you encounter the most gravity losses on descent as opposed to ascent where you have the most fuel and lowest TWR at launch, where gravity losses are most intense.