Geostationary satellites

I only saw Part 1, and I remember a scene when scientists decided to boost their communication satellites into a geostationary orbit to hide of the Sun "behind" the Earth.

Apart from how those satellites should get the rocket engines and necessary fuel to accomplish this feat, somebody should have told them that geostationary means stationary in relation to Earth's surface. The satellite still has to circle the Earth, only at the same speed as Earth's rotation speed. The satellites pictured by those scientists, standing still at Earth's night side, would immediately start their descent down to the surface ...