[makeshifthoop]

In the image on the bottom left, theres a graph that shows how much time Tiangong spends in the sun and in the shadows. Why does it seem like Tiangong spends a lot more time in sun than in the shadow when its a non polar orbit?

[InclinedPlane]

Imagine an orbit that went around the Earth exactly parallel to the direction of the Sun, it could be in sunlight all the time. If you tilt such an orbit a little then part of it will fall into the shadow of the Earth, but perhaps only just a small part. There are other factors at play as well, such as the geometry of the Earth's shadow against an orbit and refraction of sunsets through the Earth's atmosphere.

[7952]

Maybe it is connected to the tilt of the earth? It orbits the equator rather than the ecliptic plane of the sun.