That would be a lot of terrain for humans to survey, but lately we're seeing how sophisticated, ocean-going robots might do most of the heavy lifting. One particularly interesting example is the Saildrone Surveyor, which has just successfully proved its mapping capabilities across a maiden voyage between San Francisco and Hawaii.US company Saildrone first emerged in 2018 with a 23-ft unmanned surface vehicle, which is propelled by the wind and uses solar energy to power onboard electronics that include marine and atmospheric sensors. With the ability to operate autonomously or be controlled remotely from shore for up to 12 months at a time, these long-term surveying capabilities were soon put to work by researchers in Australia to explore the Southern Ocean.