Coral cover on the Great Barrier Reef has declined by 50% over the past 30 years, yet scientists can only stay underwater to study this crucial resource for 3 hours at a time. The RangerBot, a multi-function, autonomous underwater vehicle, will monitor water quality, map reefs, and help manage invasive species. It will benefit not only Earth's largest living organism, but also the more than 69,000 people who depend on the Great Barrier Reef for their livelihood (and one day, the one billion people globally who depend on coral on reefs for food and income). Over one year, existing robot designs will undergo major changes to their onboard technology to create the only fully autonomous, affordable, reef preservation solution.