this one always bugged me a little
a rocket takes off. let's say it's going upwards at 1 m/s at some short time after takeoff. why can't it then reduce (not to zero) acceleration such that it stays going upwards at 1 m/s all the way out of the gravity well? don't aim for escape velocity, keep the velocity at exactly 1 m/s until you're out.
yes, I know - Tsiolkovsky, reaction mass, delta-v etc etc clearly that's wildly impractical
but MUST the rocket achieve its 'escape velocity' in order to escape? why can't we have a casual stroll out of the gravity well?
escape velocity applies for an unpowered vehicle, right? throw a rock, it's gotta be going at least at the escape velocity or it won't escape. but throw a rock that's propelling upwards itself all the way out ...
if I want to climb stairs, I propel myself gradually on every step, I don't require that I launch myself off step 1 with the speed to get me to the top.
what am I missing here?
a rocket takes off. let's say it's going upwards at 1 m/s at some short time after takeoff. why can't it then reduce (not to zero) acceleration such that it stays going upwards at 1 m/s all the way out of the gravity well? don't aim for escape velocity, keep the velocity at exactly 1 m/s until you're out.
yes, I know - Tsiolkovsky, reaction mass, delta-v etc etc clearly that's wildly impractical
but MUST the rocket achieve its 'escape velocity' in order to escape? why can't we have a casual stroll out of the gravity well?
escape velocity applies for an unpowered vehicle, right? throw a rock, it's gotta be going at least at the escape velocity or it won't escape. but throw a rock that's propelling upwards itself all the way out ...
if I want to climb stairs, I propel myself gradually on every step, I don't require that I launch myself off step 1 with the speed to get me to the top.
what am I missing here?