Area: Tranquility
Category: Kill drones
Vehicle type: Either
Goal: Destroy as many drones as you can in 1 minute
Score for Gold: 24

Strategy #1:

Move a little towards the ramp so drones from three of the spawn points can find you, then stand or helicopter hover in place, keep turning and firing.

Strategy #2:

Because of all the boxes and stuff the drones have a harder time getting to you than in other drone based challenge mission. Compensate by staying in robot mode and moving around within the area, turning with the L and R buttons as needed. If you're using a vehicle mode that gives you a rapid fire laser while holding down the Y button (as opposed to the slower red shots) it is a very good weapon to use, and while walking around you should get plenty of green orbs to keep your weapon energy up.

Strategy #3:

The prison bus is my vehicle/bot of choice for drone missions and melee missions (although I use a flying vehicle for one particular melee mission). The prison bus has high energy levels that don't deplete too quickly in bot form when firing it's primary weapon.

Strategy #4:

Stand in front of the ramp and strafe-walk back and forth shooting at the drones from the spawn points on either side. Don't be too close to the ramp, you have to be a few steps back from it for the spawn point behind you to activate. Watch the radar, when one of those gets close enough turn around and kill it then turn back to face the ramp again.