Extra speed is good.
What happens when they want to slow down?
Does it take the same amount of time and distance to reach orbital speed?
Slowing down - not quite as good.
The thrust is small. These are used after the satellite is in orbit, to maintain orbit and “attitude,” which is the direction they point.
IIRC, the atoms are ionized then accellerated through a magnetic field. Total mass of xenon on a satellite is maybe 50 - 150 pounds.
Slowing down, reversing, etc. is done by firing in the opposite direction.
Just to add my 2 cents.
There are 2 ways to measure a rocket’s effectiveness: thrust and specific impulse. The first is essentially the total power output, while the latter equates basically to fuel efficiency. You usually get one at the expense of the other. Ion thruster deliver good specific impulse, but low thrust.
For launch you need high thrust to combat earth’s gravity, so chemical rockets are still a must at this point. Once in orbit, however, specific impulse is more important because gravity is no longer slowing you down and robbing your fuel efficiency. Even if the engine thrust is tiny, none of it is wasted. It’s here that ion thrusters are most useful, because with high specific impulse you can get more total speed per pound of fuel.
There are still times when high thrust is needed, however. That is when engine burns at specific orbital nodes are required, such as orbital injections, if you want a close orbit of Mars instead of a fly by, for example.
That’s about the limit of my rocket sciencery.
They just use the air brakes to slow down. Now we’ll just call them space brakes.
That’s why you turn over halfway there and slow down.