What is?

I'm going to start explaining some of the Satellite 'talk' or 'lingo' with a "What is" post every now and then. This should end up being quite useful.

What is Fixed Satellite Service?

Fixed Satellite Service (FSS) refers to a satellite service which uses fixed terrestrial terminals.
In other words, FSS is any satellite service where the ground station does not change locations frequently.
Consumer satellite television is the most popular application of Fixed Satellite Service.
The opposite of FSS is Mobile Satellite Service (MSS)

Source: Tech-Faq