Explain the concept of Sun synchronous orbits

Sun-synchronous orbits (SSO) are a specific kind of polar orbit. Satellites in these orbits are able to keep the sun in the same relative position as they view the Earth below. This is achieved by having the orbit precess (rotate) approximately one degree each day, in the same direction as the Earth's rotation. This means that the satellite passes over any given point of the planet's surface at the same local solar time, providing consistent lighting conditions which is useful for applications such as imaging, reconnaissance and weather satellites.

Here are the steps to understand the concept:

1. Understand Polar Orbit: A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of (or very close to) 90 degrees to the body's equator.

2. Understand Orbit Precession: Precession is a change in the orientation of the rotational axis of a rotating body. In an orbit, it can be thought of as the rotation of the orbit itself.

3. Sun-Synchronous Orbit: In a Sun-synchronous orbit, the satellite's orbital plane precesses with the same period as the planet's solar orbit. This means that the angle between the orbital plane and the planet's equatorial plane changes at the same rate as the planet's solar day.

4. Consistent Lighting Condition: Because the satellite's orbital plane precesses at the same rate as the planet's solar day, the satellite will pass over any given point on the planet's surface at the same local solar time. This means that the lighting conditions will be the same every time the satellite passes over.

5. Applications: This consistent lighting condition is useful for many applications. For example, it allows for consistent imaging conditions for satellites taking pictures of the Earth's surface. It's also useful for weather satellites, as it allows them to consistently monitor the same areas at the same time of day.