Find The Automatic Tracking Missile Pod:

When you first get out from the outside terrain, you will find yourself in the parralel lab. Destroy the main power system (the thing that when blown up will clear that level of all enemy territory, or the little green or violet parts where you cannot step on). Then, go to the upper-right corner of the first level of the parralel lab and walk all the way through a hidden passage on the top-left corner of that spot. There, you will find a hidden transporter, which will take you to where you will find the ATMP-R5 (Automatic Tracking Missile Pod). To go back, simply go back through the hidden passage.