Let's talk about ghosts (sorry Non-Biological Entities) and psionics, in particular telepathy. Now maybe they are the departed; maybe they are spirits that never wore flesh (at least not their own). Sometimes they get loose and that is usually bad news.
Ghosts start with telepathy automatically. It's just more interesting that way. They roll a straight 2d6 for psionic strength.
Without life detect turned on (and paid for normally) the living (biological entities) are very hard to notice: throw the NBE's strength + the person's Intelligence or less on 3d6 (3d6 are also handy to have around if the ghost starts throwing daggers.) NBE's
Telempathy can be used to send emotions normally. Not all ghosts send fear waves. Some can be quite benign and comfort humans. A powerful NBE could provoke a riot among a crew with just this ability and draw in the increased brainwaves and metabolic energies.
Read Surface Thoughts works normally as well but the target may experience a sudden chill (8+ to notice DMs Int 10 +1 Int 12 +2). This ability may leave cold spots infra red equipment can spot (6+ DMs for Elect or Recon skill). This ability will let them perceive a human they know and their surroundings.
Send Surface Thoughts is not quite as simple as hearing a voice. NBEs often communicate through non-verbal means. You might see a message scrawled on a bulkhead or a shadowy figure. A rule of thumb is the lighter and more distinct the figure the less you have to worry about. Shadowy or dark wraithlike forms are bad news.
These forms are psionic projections. A video or holo recording might catch a small ball of light. This level of activity produces a semi permanent cold spot the an anti-hijacking program can detect automatically. The cold spots turn up on infra red equipment (4+ DMs for Elect or Recon skill).
This level of activity may also cause minor malfunctions on control panels nearby.
Probe is where things get very scary. A NBE probing a human mind will run roughshod over a person's memories and take the form of deceased family and friends or more primal terrors who will berate the victim. NBEs with any brains will do this when the person is sleeping and make an attempt to take the form of a nightmare. The person wakes up exhausted (-1 or -2 End) and can't count that day for healing purposes. EEG and some hormonal tests run on the victim's blood may provide evidence of outside interference. At this point a cold spot will turn up if anyone searches for it.
Assault is usually not found in most entities used for engine duty for obvious reasons. But a few sneak by screening and a few are used for the high acceleration ships. Assault will render an unshielded mind unconscious and inflict up to 2d6+6 hits. The NBE can reduce this to keep their target alive. The wounds inflicted are added to the NBE's psionic points. Having unshielded crew can make things tough for a psionic defender really fast. Check your psi shields twice daily.
The nastiest tricks an NBE can pull are using the teleport power. A level of 5 or more will allow them to make small objects vanish, or make people spit them up. This sort of activity is rarely done by canny NBEs as it has lead to radiation sweeps of ships (or their scuttling by dropping them in suns.)