There is no 100% protection against abductions, not even with the satellite dish. And being in the science career only improves the odds of getting abducted, but it can also happen to sims that never interacted with anything remotely alien.
Should that happen to you, here is a handy trick: You will notice your sim walking outside and the queue will say "investigate strange light". Now hit pause, enter testingcheats true and then shift-click on your sim. Select Resetsim and the sim will not get abducted. I'm not sure about the timing - I reseted my sim I didn't want to get taken when he looked upwards (already engulfed in the glowing ray), but any time earlier should work, too.