This sounds like a Focus. Make it Durable (doubles its defense, making it tough to damage) and Universal (so others can use it). The whole "only the alien engineer(s)" can fix it is just part of how you've defined that the focus can be repaired.
If this is a super heroic game, I wouldn't let this character accumulate devices they hadn't paid for. Unless all of the characters have the same option, it sounds like you're enabling this particular character to overpower/overshadow the other characters. While it might seem to make sense from the character perspective, it doesn't, IMO, make dramatic sense for a game.
If that's a typo, and you meant, "tech powers that he has paid for," then it's just more of the same foci-based powers. And I'm fine with that.