What defines a sun-synchronous orbit?

A sun-synchronous orbit is designed to maintain consistent lighting conditions for ground observations, which occurs because the satellite crosses the same area on Earth at the same local solar time. This enables satellites to capture images or data of the Earth's surface under uniform lighting conditions, which is crucial for various applications such as agriculture monitoring, landuse classification, and climate studies.

The specific alignment with the Sun ensures that as the Earth orbits around the Sun throughout the seasons, the satellite's orbit adjusts slightly to maintain this time consistency regarding solar position. This characteristic is particularly important for remote sensing applications, where shadows and lighting can greatly affect the quality and comparability of images taken over time.

In contrast, other options touch upon aspects of satellite motion but do not accurately describe the operational purpose of a sun-synchronous orbit. For instance, an orbit that allows for crossings at varying local times would not provide the same advantageous consistency of lighting as a sun-synchronous orbit does.