ALTEX Arctic Cruise
October 7 - November 7, 2001
Tromso, Norway to the Arctic Circle
October 8, 2001: Day #3
Mike Pinto writes: We departed Tromsø Sunday afternoon and began steaming towards our first test site in protected open water. We arrived on site Monday morning and began preparation by deploying the TrackPoint hydrophone (used to track Dorado) off the back deck and finalized ballasting of Dorado. Dorado was assembled in the long configuration that included the full science payload (ice profiling sonar, 2 CTD instruments, nitrate analyzer (ISUS) and an optical back-scattering device) and the buoy launch system.
The first test mission was programmed to dive the vehicle to 15 meters, travel for 3 minutes at 3 knots, and return a short distance away. After ensuring the vehicle was pointed away from the ship, the mission was started. Shortly after the start, the mission aborted and the vehicle returned to the surface (so that’s why Dorado’s designed with slight positive buoyancy). In reviewing the data logs, it was determined that the vehicle dove to 35 meters under power when the control system automatically shut down the propulsion system (pre-determined safety parameter) and returned to the surface.
The vehicle was retrieved, software parameters and system rechecked and a second mission commenced using the same test profile. Unfortunately, the second mission provided similar results. One complication after the second test occurred while retrieving the vehicle. Normally the radio transmitted TCP-IP system would give us a GPS fix but it was not operating for some unknown reason. Complicating the situation was that the Healy was on station awaiting a delivery of batteries by a commercial boat and we could not move closer to the vehicle after it returned to the surface. This resulted in Dorado being slightly misplaced for about 2 hours even though we had a radio beacon fix. We all spent the next several hours on the bridge with our eyes glued to binoculars scanning the horizon for the vehicle while DJ Osborn and Drew Gashler were in the RHIB (rigid-hull inflatable boat) searching. After several hours without success , a portable tracking device was deployed by DJ and Drew and, after a short period, the vehicle was spotted by DJ and returned to the Healy.
Later in the day Mark Talkovic successful tested the Phantom ROV (on loan from NASA Ames) and brought back video of the Healy’s screws. The ROV will be used in case of the need to rescue the AUV under the ice.
That evening, a game plan was developed by the AUV team. An important decision had to be made to either stay in the test area to debug and retest or begin moving north. It was critical that we begin moving north as soon as possible due to the high latitude of the ice and operational days becoming shorter and shorter. It was decided by the group to head north immediately, debug and reconfigure the vehicle while underway, and test again prior to operations in the ice.