Geostationary Orbit – Approximate altitude above Earth A geostationary satellite remains fixed relative to a point on the equator. What is its approximate altitude above the Earth’s surface?

Introduction / Context:
Geostationary satellites orbit with the same angular velocity as Earth’s rotation, appearing stationary over a longitude. This requires a specific orbital radius and therefore a characteristic altitude used by communication, meteorology, and broadcast satellites.

Given Data / Assumptions:

• Geostationary orbit is circular, equatorial, and prograde.
• Earth’s sidereal rotation period determines the orbital period (about 23 h 56 min).
• Standard gravitational parameter of Earth is assumed.

Concept / Approach:

Setting the orbital period equal to Earth’s sidereal day gives an orbital radius of roughly 42,164 km from Earth’s centre. Subtracting the mean Earth radius (about 6,378 km) yields an altitude near 35,786 km, commonly rounded to 36,000 km.

Step-by-Step Solution:

Verification / Alternative check:

Public ephemerides for GEO satellites and standard references agree on 35,786 km altitude, often rounded for instructional purposes.

Why Other Options Are Wrong:

26,000 and 30,000 km are too low to maintain geostationarity; 44,000 km is too high; 18,000 km is MEO territory.

Common Pitfalls:

Confusing orbital radius with altitude; mixing solar day with sidereal day; forgetting that geosynchronous is not necessarily geostationary unless the orbit is equatorial and zero-eccentricity.

Final Answer:

36,000 km