what is the ram-facing side of a satellite? What does it mean and why is it called "ram"-facing? Thanks.
The following picture is from a simulation for a satellite moving through the ionospheric plasma.
The Ram side is the side that points in the direction of the satellite's motion. It is called the ram side because it is the side impacting/ramming into the fluid that the satellite moves through. In this case it is the ionosphere. If the fluid's velocity is comparable to the satellite then it is a little more complicated.
The Wake side is exactly the opposite. It faces away from the the satellite's motion and thus does not impact the fluid as much. The satellite's motion creates a wake behind it like a boat through the water.