.......

Okay I want you to this for me OP:

Stick your right hand out in front of you in a fist. Put it next to the right side of your screen.

Your fist is the sun. It's actually waaaaaay far off to the right of your screen, but whatever, the analogy works.

Now, you, your eyes, are earth. You're looking at the moon. The ISS is between you and the moon.

At no point, in the ISS's path in this picture, is it NOT facing the sun. Okay?

The ISS is way closer to your eyes, than the moon is. So there's nothing between your fist (the sun) and the ISS, so it will always stay illuminated.

Make sense?

.......

Okay I want you to this for me OP:

Stick your right hand out in front of you in a fist. put it next to the right side of your screen.

Your fist is the sun. It's actually waaaaaay far off to the right of your screen, but whatever, the analogy works.

Now, you, your eyes, are earth. You're looking at the moon. The ISS is between you and the moon.

At no point, in the ISS's path in this picture, is it NOT facing the sun. Okay?

The ISS is way closer to your eyes, than the moon is. So there's nothing between your fist (the sun) and the ISS, so it will always stay illuminated.

Make sense?