Ocean surveillance satellites are typically placed in which type of orbit?

• A. MEO
• B. Molniya
• C. Low-inclination LEO
• D. Highly-inclined LEO

Answer: (D)

Coverage patterns from a satellite depend on how steeply its orbit tilts relative to the equator. For ocean surveillance you want passes that reach across most of the planet, including mid and high latitudes where vast ocean areas lie. A low-inclination orbit hugs near the equator, so it would miss large swaths of ocean regions at higher latitudes most of the time, requiring many satellites to blanket the globe. A highly elliptical orbit like Molniya favors long dwell times over high latitudes, which is great for communications with those regions but isn’t ideal for frequent, global ocean imaging or monitoring. A medium or higher altitude orbit (MEO) spreads ground coverage over a larger area but sacrifices resolution and increases revisit times for a given imaging capability. In contrast, a highly inclined low-Earth orbit gives frequent passes over much of the globe, including the oceans, while staying close enough to Earth to maintain high-resolution, timely observations. This combination makes it the best fit for continuous, global ocean surveillance.