Would it be easier to deorbit a planet that's far away (since it's moving more slowly) or not (because of oberth effect?)
sci please
>>7797946
>posting animu
https://www.youtube.com/watch?v=FiS6a1XE91M
>>7798034
I just want attention and information on astrodynamics.
for every radius there is an escape velocity, but for every radius there is also a set orbit velocity. bigger radius means smaller escape velocity but also smaller orbit velocity, and vice versa. interesting question... will do some math...
>>7798040
To be honest I just wanted to share the vid and you were the first person which I spotted posting animu
>>7798064
Oh, I was actually thinking for a "dropping into the sun" situation. Making something further away escape would always be easier, wouldn't it, all other things being equal?
![46bbIw8[1].png](https://i.imgur.com/MbKh2iU.png "46bbIw8[1].png")
>>7797902
>>7798064
>>7798077
tada
>>7797902
It would be easier to deorbit a planet that has less mass
>>7798404
I know what you are trying to do to the new (hypothesized) planet.
I do not approve.
>>7798404
oh then it's just making v_o zero, so again it would get easier the futher away.
>>7799455
But.. It isn't easy by any means. And the differences in "difficulty" will be in the same order of magnitude, which is well beyond reasonable-enough-to-ever-be-realistically-considered limit. Basically, deorbiting planets is not possible regardless of orbital parameters.
>>7797902
A change in velocity (prograde/retrograde) affects the opposite side of the orbit the most. Therefore the most efficient way of deorbiting something is when it is at it's apoapsis, since the periapsis would be (by definition) at the opposite side of the apoapsis, and also closest to the parent body. The orbiting object is also moving slowest at its apoapsis, hence it is more efficient to deorbit an object when it is at it's slowest.
OP, look into bi-elliptic transfers for a better explanation.
>>7797902
The Oberth Effect tells you that a rocket in motion always puts out more kinetic energy than the chemical energy of the fuel. Why? Because the kinetic energy of the fuel that moves with the rocket has to go somewhere when the fuel gets ejected and is no longer part of the rocket and so it ends up in the kinetic energy of the rocket, where else. Faster means more effective. This is not a matter of direction or type of orbital maneuver. Orisit? When you decelerate the effect get weaker and you fly in your own exaust plume.. I vote for periapsis, thrust till touch-down.
Deorbiting near asteroids/comets to tickle the sun would be nice. Live show on the Plasma Channel.
>>7797902
there is absolutely nothing easy about "deorbiting" a planet
Changing a little the subject of the thread.
I guess that this question emerged because of the theoretical planet x so.
This planet should be in a extremely exentric orbit so we`re not going to see it again if it passes through us.
"B-but what if we low the plants orbit at his periapsis?"
With our current tecnology it`s impossible.But how could it be done?
Chemical thrusters are out of question.
Beamed power thrust maybe?.Like shitloads of energy beamed through space to a mirror placed on the planet plus hundred years of continous activity should do it?
>>7799455
That's what I figured, makes sense.
>>7800081
This also makes sense.
>>7800031
>>7800697
Well yes, obviously actually deorbiting a planet isn't something that's reasonable to do, but the same thing should apply to any satellite. The original discussion was prompted by the theoretical ninth planet, is all.
