Hydrothermal vents on the ocean floors are thought to be possible sites for the origin of life on Earth. It is believed that Jupiter’s moon, Europa, is composed of rock like that on Earth but is covered by a deep ocean topped with a shell of ice. In a recent PNAS paper, NASA astrobiology researchers and their colleagues describe how they used an autonomous, robotic, submersible vehicle to explore the ocean floor with surprising results. The submersible completed a search pattern in the Caribbean south of Grand Cayman Island, identifying prospective vent targets in a preliminary simulation of what will be needed to explore under the ice on Europa. The team then followed up with chemical and microbiological sampling. They identified the site of the deepest hydrothermal vent so far discovered at approximately 5 km. In fact, in a surprisingly short distance there were three vent types hosted at different depths in different rock types. It is expected that abiotic organic matter from these vents form part of the base of a food chain for the local ecosystem, which is such a great distance from photosynthetic primary production.