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Click below to go to the Cruise Logs - (photo credit: Lophelia Coral - Open-File Report 2008-1148 & OCS Study MMS 2008-015)

DISCOVRE 2009



Cruise Log: 8/10/2009    



The return of the Microlander

Liz Baird

Microlander being deployed. [photo by Murray Roberts (SAMS)] - click to enlarge
Microlander being deployed. [photo by Murray Roberts (SAMS)] - click to enlarge
Earlier in the trip we launched the microlander, so it was with both excitement and trepidation that we approached Sunday afternoon's dive. We had several questions - Would we be able to find the lander? Would the components have remained water tight and working? Would it have recorded any data?

The sub went down around 4:30 with Dr. Martha Nizinski (NOAA) in the front and Stacy Harter (NOAA) in the back. Their first objective was to find the microlander. They had the coordinates for reference and could also listen for a "pinger" attached to the Microlander. It was a textbook search and they found the lander within 10 minutes of reaching the bottom.

Once the Microlander was found, they spent some time collecting examples of the coral located nearby. It made more sense to make the collections without the added weight of the Microlander on the front of the submersible. After a few samples were gathered, it was time to secure the lander. It was designed so that the pilot could "fly" the arms of the sub into the brackets on the lander, but that strategy proved difficult. What did work was having the pilot pick up the lander with the robotic arm and pull it onto the arms until it locked into position.

Frame grab from the images collected by the microlander while it was on the sea floor. You can just make out a crab coming into view on the left side of the coral. [photo by Murray Roberts (SAMS)] - click to enlarge
Frame grab from the images collected by the microlander while it was on the sea floor. You can just make out a crab coming into view on the left side of the coral. [photo by Murray Roberts (SAMS)] - click to enlarge
Several of the science team members watched the return of the Microlander to the deck of the ship. Precise planning and measurements meant the feet of the lander passed over the top of the railing without incident. Dr. Murray Roberts (SAMS) removed it from the sub, then rinsed it with fresh water. He then weighed the housing to make certain the containers had remained water tight, and no saltwater had leaked into the compartments. When the weight came back as desired, Murray opened the housing - a task made more difficult because the water pressure and cold temperatures deep in the ocean tightened the seal. Murray brought the components into the lab, and switched it on. He was rewarded by a flashing LED light next to a label that says "happy."

Murray connected the laptop to the Microlander and waited anxiously as the computer said "attempting to connect." Within a few seconds the "connected" message came up, and Murray broke into a big smile when he saw that there were 712 MB of data in the file. One click and suddenly he saw all the images that had been collected while the Microlander was deployed - a frame every 20 seconds for 19 hours! At first glance the images appeared to be very similar, but as he has watched the footage several times, he saw new things, such as a crab marching over the sand or a fish swimming by.

Dr. Martha Nizinski in the bow with the Microlander on the front of the Johnson Sea-Link (photo by Liz Baird) - click to enlarge
Dr. Martha Nizinski in the bow with the Microlander on the front of the Johnson Sea-Link (photo by Liz Baird) - click to enlarge
There were 60 separate files from the hydrophone. In addition to listening to them, Murray converted them into sound spectra. One of the surprising things was not only picking up the sound of the submersible during the deployment of the Microlander, but also picking up the sub to ship hydrophone communication for every dive since then, even though we were more than 5 miles away!

All channels of the current meter recorded data. The temperature recorded at the bottom is in the right range, and there does appear to be some regular variability in the current (perhaps related to tides). We believe that this is the first current data from this part of the ocean and we look forward to future analysis and modeling of the data.

At the end of the day, our results were conclusive - If Murray had an LED indicator, it would be flashing "happy."



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