Nominal orbital speed of a geostationary satellite Geosynchronous communications satellites move around Earth at an orbital speed closest to which of the following values (km/h)?

Introduction / Context:
Although a geostationary satellite appears stationary in the sky to an observer on Earth, it actually travels at high speed in space to match Earth’s rotation. Recognizing the correct orbital speed aids intuition about orbital mechanics and link dynamics (e.g., negligible Doppler for GEO).

Given Data / Assumptions:

• Geostationary orbit radius ≈ 42,164 km from Earth’s center.
• Orbital period equals Earth’s sidereal day ≈ 23 h 56 min (≈ 86,164 s).
• Speed v = orbital circumference / period.

Concept / Approach:

Using the known orbital radius and period, we can estimate GEO speed. A common rule of thumb is ~3.07 km/s. Converting to km/h gives approximately 11,050–11,100 km/h, typically rounded to ~11,200 km/h in many references and exam tables.

Step-by-Step Solution:

Verification / Alternative check:

Using v ≈ 3.07 km/s × 3600 ≈ 11,052 km/h corroborates the same magnitude. Small differences arise from rounding Earth parameters.

Why Other Options Are Wrong:

0 km/h is incorrect; 36,000 km/h and 22,800 km/h are closer to some LEO/MEO speeds, not GEO; 7,900 km/h relates to suborbital/incorrect conversion scales.

Common Pitfalls:

Confusing “geostationary” with “static”; it is stationary relative to Earth’s surface, not inertially at rest.

Final Answer:

11,200