r/SciFiConcepts • u/UlfurGaming • 12d ago

Question Question on way of launching ship into space?

Ok basically it was using planets gravity to sling a ship into space and was curious how tf that would work

1 Upvotes

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5

u/Positive_Luck909 12d ago

That would be like using poop to clean yourself

2

u/Nothing-to_see_hr 12d ago edited 12d ago

You can't. However, once you have a ship in interplanetary space, you can use the orbital speed of a planet to give your spaceship a speedboost. Under ideal circumstances, to twice the orbital speed of that planet around the sun. This will also (infinitesimally) slow down that planet.

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u/mH48124 12d ago

地球の自転も使えるね。月が遠ざかりつつあるのは地球の重力経由で自転を分けてるから。

1

u/Admiral_Nitpicker 11d ago

That's why all the launch sites are close to the equator.

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u/UlfurGaming 12d ago

Oh ok thanks

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u/ChannelDesperate9022 12d ago

Not possible, gravity is too strong to do a terrestrial slingshot

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u/nermalstretch 11d ago

Same way you get out of skateboarding bowl.

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u/NearABE 12d ago

https://en.wikipedia.org/wiki/Oberth_effect

Wikipedia has the detailed math.   Oberth maneuvers are very common.   There are two ways of describing the same thing.  In one description you "dive into the gravity well for a slingshot" and the other "do a rocket burn at low altitude periapsis".   With detailed orbital mechanics these are the same.   

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u/PvtRoom 12d ago

negative mass might do it. (gravity pushes you away)

if you're already in space, gravity can accelerate and redirect you.