Category: ru29 (Page 13 of 22)

Hey all

The end is nigh!

Challenger is now just under 500 km from the shores of Ascension, and just 130 km from leaving international waters for the last time on this mission. Over the past week or so, we have noted that she has had what seems to be a head current.

While the currents appear to have changed, Challenger is still making good time, flying over 21 km/ day.  This leads us to believe that there may be a new cohort of barnacles causing drag  once again resulting in the gliders calculation to think there is a head current. This may be problematic over the course of the next few weeks.

As we look at our schedule, our team will be arriving for the recovery of Challenger on the shores of Ascension, however if Challenger continues to keep up the pace (21 km/day) she should be in the area roughly a month ahead of the recovery team.

Because of this we are now weighing our options of way to pass the time until recovery. Two options that have come to mind thus far have been flying a circle around the island, keeping away from the fishing vessels; or revisiting the eddy sampling technique we tried near Madeira in spring of last year where we would fly a wind mill pattern through an eddy- effectively sampling its thermal structure.  As of right now theses are just ideas we are discussing and there is always the option of stationkeeping for the remaining time, however that option is by far less fascinating

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Hey All,

With Silbo now safely on shore and preparations being made  for his safe return to Teledyne Webb Research in Massachusetts, we now can focus solely on Challenger and her mission to cross the South Atlantic.

Now, just under 800 km from the southern shores of Ascension, we set our sights on what is seemingly the last stationary obstacle standing between Challenger and her destination: one last ridge of seamounts.  To prepare for their presence, we set a way point to the north of the island to account for the ~11˚ offset we have grown accustom to flying with over the past months, and with the way point being close to 900 km away we don’t have to worry about hitting it any time soon.

One oddity we have noticed while flying past the previous subsurface mountain range was that there was a noticeable oscillation in the currents

As there was little evidence in the surface current forecast to confidently say what was the cause of this, we delved deeper into the data and found two interesting clues:  the thermocline had deepened and we were flying slightly faster on dives than on climbs.

Antonio pointed out that this was a similar flight scenario as to what a glider sees when crossing a strong warm eddy which sparked an idea in his mind.  To the south west of the island of Gran Canaria, there is an eddy that remains for the most part stationary in its location and is caused by drag as the currents flow through the island chain.

Sea Surface Height

Sea Surface Temperature

Now in our scenario, the sea mounts came within reach of the subsurface flight pattern of Challenger, but did not breach the surface as the islands of Gran Canaria and Tenerife do.  Because of this fact, this warm eddy that we believe we flew Challenger through would not have a signature at the surface and would cause the thermocline to be substantially deeper

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For those of you who have been following us for a while, crossing the 221 days at sea mile stone is a big one.

This 221 Day mark is a historic mile stone set in 2009 when the glider team took the Slocum Glider RU 27 over 7,000 km and crossed the North Atlantic from Tuckerton, NJ to Baiona, Galicia, Spain.

“In spite of neptune & poseidon, the VIG club grows.” When we first started piloting Silbo in June 2011, Antonio and I started the VIG or the Very Important Glider club that we used as a way to acknowledge the gliders we were working with as they pushed the limits of what these gliders could accomplish.  And now after 222 days at sea, we are including Challenger as well.

Since deployment, Challenger has most certainly had her work cut out for her.  Promptly after crossing the shelf break of South Africa, the compass went haywire; she encountered numerous hazardous sea mounts; the deep eastward flux that she fought from February – June; the 10 day siesta in which we had no communications with the glider as she was stuck in an infinite loop underwater; diminishing battery deadlines; and of course, Barnacles!

Moving along, yesterday I gave Challenger a new way point just a little to the north east of Ascension island to try and correct for the roughly 11˚ offset we have been flying at.

However, ahead we have what looks like one last batch of sea mounts that have the potential to be dangerous, so we may need to curve our flight path around them instead of making a b-line for the island.

As it stands now, Challenger is roughly 820 km from the shores of Ascension Island so if we were to maintain >22 km/day, we should be looking at a recovery date by the end of September.

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As our dear friend Antonio exclaimed; GOAL!!!

Over the weekend, Challenger made her way out of St Helena’s EEZ and into open, successfully ducking around the last of the unfavorable bathymetry until the rocky shores of Ascension Island!

In the surface waters over the past couple of days, we have seen the circulation of a large cold core eddy as we transect the center, resulting in the oscillation of the gliders currents from North West to West. The eddy’s signature however is only seen in the first couple hundred meters and at depth we continue to see the deep north east flux shown in the image of pinzon above.

This flux should continue to help us along on the remaining 870 km that stand between Challenger and the shores of Ascension.

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Hey All

Challenger is now on the home stretch measuring in at just under 1000 km from the shores of Ascension Island!

With the way point set on the next island on our journey, Challenger is leaving behind any questionable bathymetry as she continues to fly at top speeds of 12-13 km/segment

If we are able to maintain these speeds, we could be arriving at the island as early as the end of next month.  Once there, Challenger will be recovered by a team from Rutgers, rebatteried and redeployed to continue her flight towards Brazil where we plan on making land fall near Sao Paulo.

Looking at the currents, they are still in our favor throughout the water column as we continue on to the north west.  These currents should persist in the coming weeks with just some  as we are now flying along the general flow of the South Atlantic Gyre

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Hey All,

So since Challenger’s inspection off the coast of St Helena on the 31, she has continued on her mission to Ascension, but not without first running into a few more complications.

A day after the inspection, Challenger aborted due to an issue with the digifin saying the fin was stuck hard over to one side and was unable to move it.

After some work, Dave Aragon was able to kick the fin back into operation and get her back to flying again.  However, the celebrations would not last long as the fin then managed to get stuck once again on the 4th leaving us to drift at the surface for just over a day into Tuesday as a collaborative effort between Rutgers and Teledyne Webb worked to get Challenger flying again. But after a long day of testing and analyzing data, the team was once again able to pull through and get the glider flying and on her way.

Now the currents from both the glider and ocean models are showing a strong flux to the north which can also be seen in the mere speeds we are reaching now with our new clean glider: consistently > 25 km!  Hopefully these currents will persist in the coming days as we continue to push onwards to Ascension.

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Hey All

Here are a few of the pictures that were taken during the inspection / cleaning mission conducted by James and Hannah Herne aboard their ship the Carpe Diem last week on July 31.  As we can see from the pictures, Challenger was pretty heavily bio-fouled, but since James and Hannah were able to give her a good scrub, our speed has returned and she has returned to flying near 27 km / day!

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Hey All,

It looks like everything is fine once again for Challenger now after flying at speeds of 30 km/day:

However, towards the end of the day yesterday, we did run into a small complication.  After we thought that everything was fully operational once again with Challenger, she aborted due to an error with the digifin. What triggered this abort was that the fin got stuck to one side and was unable to free itself:

After looking over the data, the glider was then sent back on a test dive which provided some positive results.  Since then Challenger has been sent on her way with a way point on Ascension Island.

The depth average current calculated by the glider are showing a flow to the North West in a favorable direction so we hope this stroke of luck will continue in our favor. Tomorrow we will update everyone on imagery from Antonio’s Cube to get an idea of what we will be seeing as we make our way through the weekend.

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After a very long night of running tests, and an even longer day full of tours of the lab, the day is done and the glider team can relax a little.  Upon arrival to the glider around 2am, the team started communications with Jim on his boat off of St Helena as he reported that Challenger was completely covered in biology.  From mats of algae to clouds of barnacles and a mysterious something-or-another that was interfering with the tail, our glider seemed to have quite a hefty coat over her.  Soon after, members of the crew jumped in the water with an underwater camera to document the  best they could the condition of the glider- then they scrapped it all off.

Once we had confirmation that the glider was clean and in one piece, we began running the test missions, including dives to 60 m, 500 m, and 1000m to test everything from the glider’s weight in the water, status of the CTD sensor and steering ability.

Not only did Challenger appear to be operating well again, but she flew up near 30 km/day! compared to our post siesta status, where we have been averaging out at about 12, this is incredible news as we have now regained >90% of the speed we managed at the very beginning of the mission.

With the voltage our batteries we have left and our newly attained velocities, we are confident we can now push onwards towards Ascension and recover and rebattery there within the next two months.

Tomorrow Antonio will update us with his cubes, but it looks like the currents are all headed North West in the direction we want to go, so hopefully with our newly cleaned glider, we will make some good progress over night as our glider team takes some very well deserved rest.

Great Work Team!!

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unlike waiting in line at the dmv, this has developed astonishingly quickly.

Since late last week, our friends down in South Africa who helped us with the deployment of Challenger, came through for us once again getting our satellite phone on board the ship the RMS St Helena just before it left port for the island it is named after.

Over the weekend, the boat steamed onwards arriving on the island early today where the phone was passed on to Jim Herne.  Jim was then aboard his vessel with a crew on their way out to the gliders latest position by 1pm EDT and plans on arriving at the location in the wee hours of the morning.

Then around 2am the fun really begins as the glider team will be awake on the phone with Jim and his crew as they get in the water and inspect Challenger, relaying their findings over the phone.  After snapping a number of pictures we will give them instructions on how to clean it, followed by a number of test missions that will run through the night that by morning will give us an idea of whether we have Jim pull the glider on board or we continue our flight on to Ascension Island 1200 km to the North West

for those of you who are night owls, Tina will be updating the face book page in real time throughout the evening’s operations with the latest news of what is going on: https://www.facebook.com/rutgers.cool

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