Why does the ISS orbit Earth?
Show answer & explanation
Answer: Constant sideways velocity
Constant sideways velocity ✓ — Correct! ISS orbits ~400km altitude at ~28,000 km/h (7.66 km/s). It's in continuous free fall toward Earth while moving sideways fast enough that Earth's curvature makes it keep missing the ground. No rockets needed to maintain orbit (just occasional boosts to counter minimal air drag). Same principle as all satellites. Astronauts experience microgravity—constant free fall!
Atmosphere keeps it floating — Wrong. ISS orbits above 99% of atmosphere. Thin remaining air creates drag requiring occasional boosts, but doesn't hold ISS up.
Magnetic levitation holds it — Wrong. ISS doesn't use magnetic levitation. It orbits through velocity—moving sideways fast enough to continuously fall around Earth.
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