Tower 1 Exterminate Key Farming?

[Lotsacake]

Hey, everyone!

I've tried farming Tower 1 Exterminate keys on Apollodorus, Mercury and Kiliken, Venus, but I've had no luck finding any so far! 

I have a ton of the other Tower 1 keys now, and that's about it... Does anyone have any other mission suggestions to farm T1E keys? Much appreciated in advance!

[PeanutMonster]

I've got some T1 keys from Jupiter and Earth Interception

Edited July 24, 2014 by PeanutMonster

[Saravind]

t1 survivals used to be good for keys