5.1 Experiment Description

This section describes the hardware, procedures, and personnel used in the ACS testing described in this chapter.
The ACS testing is performed in the Neutral Buoyancy Research Facility (NBRF) at the SSL. The tank of water is 50 ft in diameter, and 25 ft. deep.

Figure 5-1 The neutral buoyancy tank at the Space Systems Laboratory

Ranger NBV is hoisted into the water by a crane and released. The data in this chapter was collected with the vehicle free flying about 10 to 15 ft. under the water and roughly in the center of the tank. Two remotely controlled porthole cameras in the walls of the tank near the surface along with a pair of boresight cameras in the nose of the vehicle allow the operator to monitor the position of the vehicle within the tank. A fiber optic umbilical from the vehicle to the control room carries operator commands to the vehicle, and also carries telemetry and video from the vehicle to the control room.
In the control room, the telemetry is displayed and recorded on a SGI based control station. The same computer takes commands from the operator (Operator Interface - Chapter 3), which are then passed to the vehicle. Monitors surrounding the control station display the video from the vehicle and tank porthole cameras. A video control system controls camera tilt, pan, and zoom, and also provides video recording capability.
Once the vehicle is in the water, the ACS software is activated and initialized. Filters are initialized, and bias estimation algorithms are run. Following this, the RBCs are used to trim the rotational buoyancy of the vehicle. The operator then uses the translational hand controller to position the vehicle in the middle of the tank. At this point, a trajectory is commanded, and the ACS uses the selected controller to track the trajectory while data is recorded.
A small crew is also required to support ACS testing. Two divers monitor the vehicle in the water. The divers tend to the fiber optic umbilical, and support vehicle ingress and egress. A Deck Chief monitors the operation, and is responsible for diver safety. In the control room, the pilot observes telemetry and video, and controls the vehicle. Additionally, a video operator tracks the vehicle in the tank with the two porthole cameras.

Figure 5-2 Video control consoles in the control room