How does a rocket reach orbit instead of just going up?
Quick Answer
A rocket must accelerate sideways fast enough to keep falling around Earth, not straight back down. Low Earth orbit requires about 7.8 km/s of orbital speed, plus extra to overcome gravity and drag.
The Full Story
Reaching orbit is about speed as much as altitude. A launch vehicle climbs through the atmosphere and then pitches over to build horizontal velocity; at roughly 7.8 kilometers per second in low Earth orbit, the spacecraft keeps missing Earth as it falls. Rockets also need extra delta-v to overcome gravity losses and atmospheric drag, so the total requirement is higher than the pure orbital speed. Different destinations need different speeds: the Moon, Mars, and deep space all demand substantially more energy.
Key Facts
YouTube Angle
Suggested video title for this topic:
"Why orbit is really a speed trick, not a height trick."
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