Unmanned wind-powered vehicle circumnavigates Antarctica

Unmanned wind-powered vehicle circumnavigates Antarctica
The Saildrone vehicle. Image courtesy of Saildrone

A wind-powered unmanned surface vehicle (USV) known as a Saildrone has circumnavigated Antarctica equipped with climate-grade sensors to collect data on ocean and climate processes in previously unchartered waters.

The seven-metre (23-foot) long USV was launched from Southport in Bluff, New Zealand, on January 19, 2019 and returned to the same port on August 3 after sailing 13,670 miles over 196 days. It is the first unmanned system to complete an Antarctic circumnavigation.

Powered exclusively by wind and solar energy, the Saildrone USV can operate for up to 12 months with a zero-carbon footprint.

The purpose of the voyage was to gain a better understanding of ocean processes and the changing climate. Carbon fluxes were measured using an instrument developed by the US National Oceanic and Atmospheric Administration (NOAA), providing new data on the rates of carbon uptake in the Southern Ocean.

“These exciting, high-resolution observations from Saildrone during its circumnavigation of the Antarctic provide valuable ground-based datasets for scientists to understand the Southern Ocean better and evaluate the models we use to predict weather and climate,” said said Sebastiaan Swart, co-chair of the Southern Ocean Observing System (SOOS).

“Having another autonomous platform that can survive the Southern Ocean is both a technological feat and an opportunity to get us closer to solving the ocean CO2 sink puzzle!  Preliminary results suggest that we also observed CO2 outgassing during winter months in the same region as the floats measured previously. CO2 outgassing from the ocean to the atmosphere occurs when ocean pCO2 levels are higher than atmospheric levels,” explained Dr. Adrienne Sutton, an oceanographer with the NOAA Pacific Marine Environmental Laboratory (PMEL) Carbon Group.

The standard configuration of a Generation 5 saildrone includes a seven-metre (23-foot) hull, a 2.5-metre (8-foot) keel, and a five-metre (15-foot) tall solid wing. This regular saildrone wing has an operational wind range up to 60 knots; however, the waves encountered in the Southern Ocean were too much for this tall and slender wing.

A new type of wing was therefore specifically designed for the Southern Ocean. The lower aspect “square rig” is incredibly strong and is designed to deal with the huge forces of being rolled and submerged by 15-metre (50-foot) breaking waves.

“While the square rig has less performance range than the regular saildrone wing and struggles to sail upwind, it does a great job of sailing downwind and can still get you where you need to go in the Southern Ocean,” said Saildrone founder and CEO Richard Jenkins. “You inevitably sacrifice manoeuvrability for survivability, but we have created something that gets the job done and that the Southern Ocean just can’t destroy!”

Saildrone is currently a global fleet of unmanned surface vehicles, targeting planetary coverage.

This mission was sponsored by the non-profit Li Ka Shing Foundation and all data made publicly available at no cost in order to accelerate understanding of critical processes affecting humanity.

Read more about the project here.