8
votes
Accepted
What is the relationship between the radius of the Hill sphere and escape velocity?
This is where it goes wrong:
$$\Delta v = \sqrt{v_2^2 - v_1^2}$$
You're taking the difference of the squares of the velocities at a low lunar orbit, and the perilune of the transfer orbit.
But really, ...
7
votes
Accepted
At what point does an object lose 50% of escape velocity?
As a spacecraft drifts outwards, slowing down, it stays at escape velocity. The current escape velocity, that is. Escape velocity depends on distance and an object further out needs less velocity to ...
3
votes
Apollo 11 mission report shows velocity well below escape velocity thousands of km on the way to the Moon
It is normal for a spacecraft to slow down as it coasts towards the Moon. The spacecraft is still in Earth orbit and is being pulled by Earth’s gravity during its entire trip to the Moon. During the ...
- 1,977
3
votes
When a spacecraft reaches the event horizon of a black hole, what happens to its residual gravitational potential energy?
The object's mass and energy together add to the mass of the black hole. Mass is a form of energy. There's even a concept of a kugelblitz formed by nothing but photons. While photons are massless, ...
- 73.2k
2
votes
Accepted
Does the payload capacity of an interplanetary launch rocket increase with decreasing fuel mass or with increasing escape velocity?
Your thrust, depends on the reactive mass ejected x ejection speed.
Your acceleration depends on your thrust and your mass.
Escape velocity is more or less a fixed speed cost for leaving the planet. ...
- 12.6k
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