Clean or replace the coil sleeve first if its getting stuck in the coil. If the ball just sits there and the motion is fluid, its likely the switch.

If it's not firing the ball out, it is likely that your switch there is not function properly. Happened to me a lot on the fork switches on my space station. I would just suggest buying a new switch and replacing it. Would be a quick and easy replacement.

http://www.pinballlife.com/index.php?p=product&id=1279
or
https://pinside.com/pinball/forum/topic/looking-for-outhole-switch-17-1067
or
http://www.pinballspareparts.com.au/parts-by-machine/williams-parts/17-1067.html

It is also listed on page 50 of the space station manual.

pinball life should be a direct replacement but its not quite clear 100%, if you email them they could let you know. Otherwise the one from pinball spare parts is listed as a direct replacement so it should be good but it will cost more with shipping. They are supposed to be the same though. Marco might even have it without that reference number listed...

Just be sure nothing is bent or anything like JeffZee said. If you manually move it and it kicks the ball fine, no sticking etc. Likely intermittent switch. I know i'm repeating myself I just don't like giving bad information. lol. If you want I can grab a picture of mine when I go out to the garage a little later today too.