Suppose that the technology exists for a spacecraft to launch with low velocity. Horizontal velocity is 0 and after brief acceleration the vertical velocity is constant at 30m/s. After 4 days the craft reaches the high-earth orbit and the propulsion is turned off. What would happen then?
In: 4
30 m/s * 4 days = 10,400 km. The gravitational acceleration at that altitude is 1.4 m/s^(2) so it would stop moving upwards in 21 seconds, gaining only 0.3 km of additional height before falling down to Earth.
A rocket trying to do that would run out of propellant after ~10-15 minutes, by the way, just to counter gravity. At that time it’s at an altitude of roughly 20-30 km, still far away from space.
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