Which statement correctly describes the relationship between geosynchronous and geostationary orbits?

• A. A geosynchronous orbit is a specific type of geostationary orbit.
• B. A geostationary orbit is a specific type of geosynchronous orbit.
• C. They are identical; all geosynchronous orbits are circular.
• D. A geosynchronous orbit is always equatorial.

Answer: (B)

Understanding this relationship comes down to orbital period and how the orbit is oriented. A geosynchronous orbit has a period of one sidereal day, so the satellite comes back to the same longitude each day. But it doesn’t have to stay in one spot in the sky; if the orbit is inclined or eccentric, the ground track will move north-south over time or vary in shape. A geostationary orbit is the special case where the satellite’s path is circular and lies exactly above the equator, so it remains fixed at one point in the sky as the Earth rotates.

Therefore, geostationary is a subset of geosynchronous: all geostationary orbits are geosynchronous, but geosynchronous orbits can have inclinations or eccentricities that prevent them from being fixed over one spot. The other statements fail because a geosynchronous orbit does not have to be equatorial or circular, and not all geosynchronous orbits are fixed like geostationary ones.