Empirical Earth · How We Know — History & the Cosmos

What an orbit is — and why the ISS cannot fit on a flat Earth

The claim

“The ISS is a light on a track; no globe or orbit needed.”

What is measured

At ~415 km the ISS must travel 7.67 km/s to stay in free-fall. That gives a 92.9-minute period and ~15.5 laps a day, so its crew sees ~16 sunrises and ~16 sunsets every 24 hours. Each lap carries them around a sphere and through its night side.

What would show this is wrong

an ISS pass whose timing or 92.9-minute period contradicts orbital mechanics, or a “satellite” fixed relative to the ground at the ISS’s altitude.

Sources

  1. The International Space Station’s orbit. The ISS orbits in low Earth orbit at roughly 413–422 km altitude, inclined 51.64°, at about 7.67 km/s with a 92.9-minute period — about 15.5 orbits p link
  2. Types of Earth orbit and their altitudes. Orbits are classified by altitude and period: low Earth orbit (LEO, ~300–2,000 km, e.g. the ISS), medium Earth orbit (MEO, including GPS near 20,200 link
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