What is a satellite ground trace?

• A. The projection of a satellite's orbit on the earth's surface.
• B. An imaginary line from the satellite to its nearest point on the ground below it.
• C. A line connecting the series of ground-control stations the satellite passes over as it orbits.
• D. The outline of countries shown on the map when weather images are displayed on a computer monitor.

Answer: (A)

A satellite ground trace is the projection of the satellite’s orbit onto the Earth’s surface. Imagine tracing the path that the satellite would appear to make on the planet as it flies around in space; that path is the ground trace. It follows the sub-satellite point—the point on Earth directly beneath the satellite—over time, while the Earth's rotation shifts where that point lands. The result is a ground track that shows where the satellite will be overhead across different latitudes as it completes passes. This helps in planning observations, communications, or imaging because it tells you where and when the satellite will pass over. The other descriptions describe different ideas: the instantaneous line from the satellite to the ground is just the current overhead line, not the entire orbital projection; a line connecting ground-control stations isn’t about the satellite’s path; and the outline of countries on a weather map is a geographic display, not the orbital trace.