A Sun-synchronous orbit is a type of orbit that keeps a satellite in sync with the Sun's position, allowing it to capture images with consistent lighting conditions.
The orbit is designed so that the satellite passes over any given point on the Earth's surface at the same local time of day, usually around 10:30 am or 1:30 pm. This means that the angle of the Sun's rays on the Earth's surface remains constant for each pass, which is important for many applications such as mapping or remote sensing.
The reason for this consistent timing is because the Earth rotates on its axis while it orbits the Sun. This means that over the course of a year, the angle of the Sun's rays on the Earth's surface changes due to the tilt of the Earth's axis. By synchronizing the satellite's orbit with the angle of the Sun's rays, a consistent image can be captured each time.
Sun-synchronous orbits are commonly used for applications such as weather forecasting, mapping, and monitoring the Earth's environment. For example, the Landsat satellites use a Sun-synchronous orbit to capture images of the Earth's surface for a variety of applications, including land use management, natural resource exploration, and disaster response.
Another example is the Sentinel-2 satellite, which is operated by the European Space Agency (ESA) as part of the Copernicus program. The satellite uses a Sun-synchronous orbit to capture high-resolution images of the Earth's surface, which are used for a variety of applications including land use and natural resource monitoring, crop mapping, and urban planning.