OK thanks very much,
Are either considerecd essential? I can see some uility for the Thermal Sensors allowing ships a limited detection capability without going active.
Welchbloke
Are they essential? Of course they are!
The situation in Aurora (as I see it as a newby) is very likely to todays submarines. Yes, you can go active and see the enemy, if he is in range, but any enemy with passives within 10x that range will see *you* once you do this
You can also build missiles with thermal or EM seeking warheads, so you could be blown away without ever knowing you´re under attack.
Flying around with active sensors all the time is
not something I would recomend!