Is it really possible for a spaceship to stand still and turn off all engines and just be idle in one exact spot in space like it happens in particular famous tv series etc? Wouldn’t the ship just continue floating away/moving on its own until you turn the engines back on?
In: 6
No, you’re in orbit, so you’re constantly accelerating towards the nearest gravitational body.
In order to maintain orbit, you need to be moving very quickly to the side. So by the time you’ve fallen, you’ve moved far enough sideways that the body you’re orbiting is behind you.
Circular motion requires and acceleration such that a=v^(2)/r
Gravitational force is F=GMm/r^2
Newton’s second law is F=ma
ma=GMm/r^2
a=GM/r^2
v^(2)/r = GM/r^2
v^2 = GM/r
v=sqrt(GM/r) for a circular orbit. G is the universal gravitational constant, M is the mass of the body you’re orbiting, and r is the radius of your orbit.
This doesn’t require any active engines, you just need to get up to speed, and there’s no drag to bring you down. This is how the ISS and satellites stay in orbit, they’re moving very fast.
You can “park” two spacecraft next to each other by making then move at the exact same speed in the exact same direction. They won’t appear to move relative to each other, but they are still moving very fast around the planet. Over time, they will drift towards or away from each other unless you have absolutely perfect precision, but it’s hardly noticeable until several orbits have been completed.
Latest Answers