Bathymetric surveys are usually done with the goal of learning the shape and makeup of some part of the planet.
But in the case of a recent survey of the high-Andean lake Laguna Negra* the goal was twofold: learn the shape and makeup of a part of the planet and also make an expedition to another planet possible.
New Jersey-based company Aqua Survey Inc. was contracted by non-governmental agency Search for Extraterrestrial Intelligence (SETI) to travel to central Chile in December and conduct a bathymetric survey of a high-altitude lake as part of a project that aims to eventually explore lakes on other planets and moons.
The Planet Lake Lander (PLL) project funded by NASA and spearheaded by scientists from SETI is developing a prototype lander that could eventually land on Titan Saturn’s largest moon and home to several large lakes.
To test the prototype PLL principal investigator Nathalie Cabrol and her team chose a high-altitude lake in the Andes which has some characteristics that a lander might find in a mission to a lake on another planet: a volcanic environment a thin atmosphere and low temperatures. Laguna Negra was chosen also because it is fed by a glacier that is rapidly melting away so the lake lander prototype will have a chance to learn how de-glaciation affects a lake on earth knowledge it could apply to an extraterrestrial lake where de-glaciation may also be occurring. The lake lander has visited Laguna Negra two years in a row and will return next year for a several-month visit according to Cabrol.
When the team and the prototype visited the lake in the
first year they were surprised by its depth.
“There must have been an error in the latest publication because we were expecting 12-meter depth and (instead it was) a 300-meter depth” Cabrol told an audience in a recent SETI webcast about the project. “Which is an interesting thing if you have 50 meters of mooring.”
So for the second visit this last December PLL asked Eric Wartenweiler Smith of Aqua Survey to accompany the team to the lake on a three week visit and conduct a full bathymetric survey of the lake. The survey was necessary not only to determine the best place to moor the lake but also to determine the geometry of the lake and “where the microhabitats are located” so the team will know where the lander should explore Cabrol stated. The survey will also help the team compare the data the lake lander accumulates to the data provided by a formal survey to ensure that the prototype’s measurements are accurate.
Smith used bathymetric sonar equipment to map the lake and learn more about its characteristics “including some information on whether the bottom is rocky or soft weed-covered or bare scoured out by glaciers or carved by rivers and also the information needed to calculate the volume of water present” he told a reporter at The Hunterdon County Democrat after his return in December.
Smith conducted his survey from an inflatable Zodiac powered by an electric motor to avoid polluting the lake with gasoline (the water in the lake is part of Chile’s drinking water system). They camped on the banks of the lake in large dome tents but when Smith was out in his boat he took a small tent with him in case weather conditions didn’t allow him to return to camp safely according to a video he made about the trip. When he wasn’t working on bathymetry Smith helped out with anchoring and moving the prototype.
Smith has a penchant for adventure: last month he was a part of an Aqua Survey team that journeyed to Laos with technology to help find and get rid of unexploded ordinance left over from the Vietnam War.
In his video about his trip to Chile he asked the question why do people explore? He’s come up with his own answer: “I think we explore because we want to bring back something of value to our community that will be for the greater good.”
* The full name of the lake is Laguna Negra y Embalse del Yeso – Black Lagoon and Reservoir of Gypsum.