How do you get a shield in the game dark orbit?

How do you get a shield in the game dark orbit?
You can buy them for credits or uridium and the beginning quests give you 2 of them (if I remember correctly). They are named SG3N-XXX where XXX can be A01, A02, A03, B01, or B02. The 'A' series can be purchased with credits while the 'B' series are purchased with Uridium. You can then equip them in your generator slots or drones.