[Suicide Junkie]

I dont think you should be able to perform espionage on an empire you have no contact with.

Well, you can't. Though, you may be using a different definition of contact.

An infiltration factor would be nice, though... some sort of infiltration project would increase the chance of success of your later projects. There would have to be a small decrease over time, and you would lose larger amounts when attacking with a project (since the people involved expose themselves doing it).

When you are infiltrating operatives, there should be a multiplier based on your current relations.
Someone you're at war with would be very hard to add operatives to, while partnership allies would be easy to infiltrate.