The propulsion system consists of 8 ducted fans or thrusters that are used to translate and rotate Ranger NBV in the neutral buoyancy environment. Figure 2-3 shows the layout of the thrusters on the propulsion module.

Figure 2-2 The top y thruster

Figure 2-3 Thruster layout on the Propulsion Module

An early design decision was that the thruster layout should be arranged such that the vehicle would have more power for translating forward and reverse than side to side, or up and down. This would allow the it to travel rapidly from one task location to the next. Thus Ranger NBV has 4 thrusters directed along the x-axis. Not only do these provide x translation, but they also provide pitch, and yaw actuation. The 2 y-thrusters provide translation along the y-axis, along with half of the roll capability. The 2 z-thrusters provide translation along the z-axis along with the other half of the roll capability.