What does 'orbital decay' mean?

• A. An increase in a satellite's speed
• B. A gradual decrease in satellite altitude
• C. A method of space debris removal
• D. A technique for stabilizing orbits

Answer: (B)

Orbital decay refers to the gradual decrease in a satellite's altitude over time. This phenomenon occurs primarily due to the effects of atmospheric drag on satellites in low Earth orbit. As a satellite travels through the thin atmosphere, it experiences friction that slowly reduces its speed and subsequently lowers its orbit.

In the context of space operations, understanding orbital decay is crucial for satellite mission planning and management. Operators must account for this decay to ensure the satellite remains in its intended orbit for as long as possible, or to determine when a satellite needs to be decommissioned or repositioned. By distinguishing it from other concepts, such as increasing speed or techniques related to debris removal or orbit stabilization, it becomes clear that orbital decay specifically addresses the reduction of altitude due to external forces acting on the satellite.