At last the first AUV survey around a Mola! and the hunt for a coastal UAV launch site
Finally, we got to go after one of our prized experiment goals. On Tuesday 13th, courtesy of the Portuguese Navy, we not only went out to sea, but also tracked the first set of Mola's with our AUVs. 2.5 surveys in total, the first a 500m X 500m box, followed by a higher resolution 1km X 1km survey with the last survey also a 1km X 1km box interrupted by a navigation error on the Xplore-1. Data collected and logs are being analyzed here and in Porto.
The AUV team left very early at 6.15am to drive all the way to Vilamoura to board the NRP Argos, a Portuguese Navy, fast coastal monitoring vessel. This baby moved out at 16 knots and within an hour was 'on station' guided by the shore crew who were tracking any tagged fish popping up. Much to the surprise of all, two ARGOS tagged Mola's popped up about 15km off shore of Olhão; surprise because most of us had given up on the ARGOS tags and were leaning on the SPOTs to help us thru the experiment. Not so! Better still, the Mola dived a number of times and came back up. ARGOS tagged Mola-163 and Mola-164 were 52 cm long and 72 cm long Mola's respective. Not only was it a surprise that the larger Mola popped up, but it stayed up. 163 was further south, so the shore-crew (Nuno and Kanna) decided to request targeting 164 further north and east and easier to reach for the NRP Argos. Which they did. In short order, a 500m X 500m survey was quickly dispatched, with all breathing a sigh of relief. Even better, the previous night there was discussion about a possible 'Mola corridor' in the area. As a new 164 position opened up 2km away (these fish can swim about 15 km a day!) heading north-north-east, a transect line across this corridor opened up. Shore requested and crew dispatched and the Xplorer-1 cut thru the 2km with a yo-yo, no doubt collecting valuable science data. A second and larger higher resolution (one can fit more interpolated points) 1km X 1km survey was commanded via Iridum from the ship by Zé using T-REX, which was duly executed. By this time it was close to 12.45pm with the 1km square survey taking about 1 hour 20mins.
Ship and shore communicated and it was decided that it was appropriate scientifically to resample the same fish target, with a slight offset based on a new pop up to the surface by our new friend, Ms. Mola-164. Argos drifted off to the side, the Xplore moved about a KM and started what was likely the last survey of the day. 2/3rd's thru it, with Zé and João using acoustic beacons on the ship discovered that the Xplore was heading straight at them!! Repeat quizzing of range and bearing only showed the vehicle coming closer. There was no alternative but sadly to abort the mission. Which they duly did. Plus it was nearly time to recover (see the very cool launch and recovery method on this ship in the video above). The logs are now being analyzed, but it appears with no DVL (and bottom lock) and loop closure for navigation occurring with the compass only, the calibration of the compass is a likely cause
A word about the Marinha, proud inheritors of the nations enduring sea going legacy. Not only was the Argos a superb vessel for conducting AUV ops, but the crew were sharp, professional and taking it all in stride. Essentially we were given permission to do what was necessary to get our experiment underway. And for this we have much to thank the crew of the vessel and in particular Capitão-Tenente(or Lt. Cdr) Madaleno Galocha, Op's Div. CN32,Portuguese Naval Command in Lisbon. He made it all look easy!
Meanwhile, the UAV team not to feel left out, and also looking at their Neptus console, got the go ahead from the PIs to search for a spot onshore to potentially launch and operate an X8 at a range of 10km over potential tagged Molas. So off they went scouting for places, bumping down dusty coastal access roads, jamming under small culverts and trying to quickly reach the coast. And find they did, a number. But wind was picking up and Javier and Francesco alerted the team to the start of an onshore breeze which could disrupt ops at sea for Thursday. Since permissions from the coastal authorities were needed and unlikely to be obtained asap, the UAV team quickly reconfigured and went back to plug the holes in their testing program. X8-04 was quickly flown off Vila Real even as the wind was picking up and the Argos team was headed back to the dock at Olhão. But nature was a step ahead and after encountering strong headwinds to the styrofoam based light-weight X8, the UAV team decided to pack up and late in the day head home.
Everyone converged back at the farm house around 7pm to pat ourselves in the back for notching our first success but with the continued 'Democles sword' of the Diplodus situation still hanging over us. Recall, the satcom was bolted on to it, and to fly a UAV from a ship, it was the Diplodus we had set out for. UAV ops off of the Argos could simply not be possible given space restrictions, even if it was a far more comfortable ship with a very disciplined and experienced crew.
The day ended with an impromptu celebration of Frederic's birthday (remember we're in Portugal and more than anything food and anything around it, is a critical part of life) resulted in three (not one) cakes being cut. Competition with the Spanish with late night food binges was well underway! And with that, we all retired with the hope we could repeat our AUV survey tomorrow, Wednesday.