When probing through large systems with many planets, I often find it to be an inconvenience to only see 3 total messages stating that probes have launched. I often forget which planets I have already probed. Is there a way to make the queue longer?

Yes;
Zorg needs to fix it so it shows a small arrow indicating one of your fleets
probes or ships
in-route to that Planet / Moon / DF for harvest
some of the other O-Game Clone Games do have that
yellow is Esp Probe
Red is an Attack Fleet
Green is a Transport or Recyclers to DF for Harvest

I Love it

It does have different colours on the main overview but on the galaxy screens at the bottom it does only have 3lines but they do move down so the top is the last action u do