Cloaking device

Some ships and Buildings have a cloaking device that enables them to cloak a fleet

some examples:

1. cloak generator
2. shadow star
3. pirate flagship

interfearance

some technologies interfear with the cloaking technology for example the eye in the sky

(this recon vessel is equipped with sophisticated surveilance technology ... it is exposed a strong radiation that interferes with every cloaking technology, so a fleet with it cannot be cloaked ...)

newbie-cloak-protection

during your first 2 days all your fleets are protected by a newbie-cloak-protection