PLL’s New Home

Liam (r) prepares one of PLL’s 140-pound anchors for deployment. With him (l to r) are Cristian, Trey and Chris. Credit: XenoQuest Media

by Henry Bortman

The Planetary Lake Lander has been moored for the past week a short distance off the southern shore of Laguna Negra, near PLL Base Camp. Its proximity to camp enabled engineers to test its data-sampling and communications equipment. And to easily get out to the device to fix whatever annoying problems – miswired connections, transmission glitches – cropped up.

Now that the exciting world of the northwest shore has been explored and found to be a scientific wonderland, however, the time has come to relocate. A decision was made a couple of days ago to move PLL to a spot just off the northwest shore, where the waters of Victoria’s Cascade tumble into the lake, bringing with them nutrient-rich glacial sediments. This location will provide very different information than the crystal-clear, and nutrient-poor, waters near Base Camp.

Liam (standing) and Trey sail PLL toward the northwest finger of Laguna Negra. Credit: Chris Haberle

The spot chosen offered a finely tuned mix of characteristics. There was the glacial melt water, of course, fantastic for science. But there was also, conveniently, a pair of underwater landslides, discovered during Chris Haberle’s bathymetric survey of the area. That was good for anchoring PLL so it stays put for the next three months. And to top it off, the arc of the sun across the sky lined up nicely with PLL’s solar panels, so there will be no worry the scientific equipment will run short on power.

Yesterday, Trey and Liam, along with Chris and Cristian, spent the day preparing PLL for its journey to and installation in its new home. That meant, first, moving it from its temporary home to Launch Point, on the lake’s southwest shore. The advantage of working at Launch Point is that it’s the one spot along the lakeshore accessible by road.

The scientific and communications equipment had already been checked and double-checked. What remained to be done was outfitting PLL with new anchors. Two 140-pound anchors. These were too heavy to lift, so they had to be disassembled, carried onto the PLL’s pontoon in pieces, and then reassembled. While moored off the southern shore of the lake, PLL has been held in place by relatively lightweight anchors, but for it’s longer-term stay on the northwest shore, it needs to be anchored more securely.

The Planetary Lake Lander moored in its summer home off the northwest shore of Laguna Negra. In the lower left, the waters of Victoria’s Cascade. Credit: Chris Haberle

Assembling the anchors was only step one. Liam spent most of the day yesterday “flaking” the ropes attached to the anchors. This is not a problem the average person has to be concerned with, but when you’re floating on the surface of deep, hypothermia-inducing water, on a moderately unstable platform, and planning to drop overboard a pair of 140-pound anchors attached to very long ropes, it’s a good idea to prepare carefully.

You might think the best approach would be to coil the rope in a cute little circular pile. Turns out, that’s not the case. As you may have experienced with a garden hose, what appears to be neatly coiled, when pulled on, can suddenly become hopelessly tangled.

That’s not such a big problem when you’re dealing with a garden hose. But when you’re dealing with a long rope, with a 140-pound weight attached to one end, and when you are about to send that weight hurtling down through 45 meters of water, you want the rope to play out smoothly, not to snag on anything. Such as a piece of expensive equipment. Or someone’s ankle. Because whatever it snags on will (a) probably get broken; and (b) be dragged down into the deep with little hope of recovery.

So you flake the rope. Which means you stack it up in what looks like a random back-and-forth pile, but a pile that, crucially, is snag-resistant. And then you flake the other rope. And then you go back and flake the first rope again, just to be sure. And then the second rope, again. And a third time, to be really, really sure.

All this flaking was time well spent. Today, the PLL was sailed to its new location, the ropes were deployed without incident, and PLL was secured for its three-month stay in the northwest waters of Laguna Negra.

It was after that that the problem occurred. When PLL engineers pulled out their ruggedized, work-anywhere laptop to “talk” to the equipment onboard the lander, they couldn’t establish communication. That was confusing. And annoying. Here they were standing right next to the device they were trying to communicate with, a device they had communicated with successfully from the Robo Dome only the day before, and suddenly a communications link that had been working perfectly had gone awry.

Long story short: when the laptop had been in the Robo Dome, it had been attached to an external monitor. And the window for the software package that talked to PLL had been displayed on that external monitor. But out on the water, there was only the laptop. No external monitor. You’d think the software could figure that out and display the window in question on the laptop screen. But if you thought that, you’d be wrong. Instead, all it could do was issue a cryptic error message. Fortunately, once the team got back to the Robo Dome and reattached the external monitor, communication was re-established.

Now that everything’s working as it should, PLL is set to spend the next three months collecting data and transmitting it back to the IRG group at NASA Ames Research Center in Moffett Field, California. At that point, some members of the PLL team will retrieve the device and ship it back to Ames, where it will get upgraded with both new hardware and new software, before being brought back to Laguna Negra next summer.

The data that it sends back will form the basis for the development of the first version of PLL’s autonomous control software. Developing that autonomous software is the primary technology goal of the PLL ASTEP (Astrobiology Science and Technology for Exploring Planets) project. It’s not yet clear how “smart” the software will be in Year 2 of the project. Ultimately, the goal is to program PLL to make decisions on its own about what events are of scientific interest and about how best to study those events. But in Year 2, it may not implement autonomous decisions, but rather limit itself to performing the analysis that would lead to such decisions.

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