What is the approximate altitude of a geostationary orbit?

What is the approximate altitude of a geostationary orbit?

• A. 20000 km
• B. 35786 km
• C. 600 km
• D. 10000 km

Answer: (B)

A satellite stays over the same spot on Earth only if its orbital period matches the planet’s rotation. That means the orbit must complete once every sidereal day, about 23 hours 56 minutes. With Earth’s gravity shaping the orbit, this corresponds to a distance of roughly 42,164 km from Earth’s center. Subtracting Earth’s radius (about 6,378 km) gives an altitude of around 35,786 km above the surface. So the approximate altitude is 35,786 km. Lower-altitude orbits complete many orbits per day, so they cannot be geostationary.

A satellite stays over the same spot on Earth only if its orbital period matches the planet’s rotation. That means the orbit must complete once every sidereal day, about 23 hours 56 minutes. With Earth’s gravity shaping the orbit, this corresponds to a distance of roughly 42,164 km from Earth’s center. Subtracting Earth’s radius (about 6,378 km) gives an altitude of around 35,786 km above the surface. So the approximate altitude is 35,786 km.

Lower-altitude orbits complete many orbits per day, so they cannot be geostationary.