• #### When do orbital mechaniscs kick in?

From JF Mezei@21:1/5 to All on Thu Oct 14 16:08:27 2021
If I understand correctly, orbital mechanics is about your tangential
speed causing you to gain altitude as the cureve ground below you drops,
and "orbit" means you gain altitude as the same rate as you fall
towards the earth. Right ?

A commercial airliner, with good tailwind can get about 1000kmh ground
speed. or 1/25th of orbital speed. Is it correct to state that at that
speed, the horizontal speed provides inconsequential "lift" relative to curvature of earth?

At roughly what horizontal speed would your tangential "lift" start to meaningfully counter the vertical acceleration of gravity? 5000kmh ?
10,000kmh , 20,000kmh?

I assume this is a very important component of launching a rocket?

At the time of Falcon 9 first stage MECO, would it be fair to state that
it still had an angle with some vertical propulsion since it was below
orbital speed yet still gaining altitude?

Since second stage fires almost right away, does it also maintain a
slight vertical vector in its propulsion to prevent it from losing
altitude until it has accelerated to orbit? Does this slight vertical propulsion component last throughout first second stage burn, but the propulsion becomes purely horizontal for the second burn?

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• From Sylvia Else@21:1/5 to JF Mezei on Fri Oct 15 12:34:41 2021
On 15-Oct-21 7:08 am, JF Mezei wrote:
If I understand correctly, orbital mechanics is about your tangential
speed causing you to gain altitude as the cureve ground below you drops,
and "orbit" means you gain altitude as the same rate as you fall
towards the earth. Right ?

A commercial airliner, with good tailwind can get about 1000kmh ground
speed. or 1/25th of orbital speed. Is it correct to state that at that speed, the horizontal speed provides inconsequential "lift" relative to curvature of earth?

At roughly what horizontal speed would your tangential "lift" start to meaningfully counter the vertical acceleration of gravity? 5000kmh ? 10,000kmh , 20,000kmh?

I assume this is a very important component of launching a rocket?

At the time of Falcon 9 first stage MECO, would it be fair to state that
it still had an angle with some vertical propulsion since it was below orbital speed yet still gaining altitude?

Since second stage fires almost right away, does it also maintain a
slight vertical vector in its propulsion to prevent it from losing
altitude until it has accelerated to orbit? Does this slight vertical propulsion component last throughout first second stage burn, but the propulsion becomes purely horizontal for the second burn?

Orbital mechanics applies all the time - even when you are walking