Scientists have discovered new evidence that the subsurface ocean of Saturn’s moon Enceladus contains a key building block for life. The team directly detected phosphorus in the form of phosphates originating from the moon’s ice-covered global ocean using data from NASA’s Cassini mission. They found abundant phosphorus in plume ice samples spraying out of the subsurface ocean. The Cassini spacecraft discovered Enceladus’ subsurface liquid water and analysed samples in a plume of ice grains and gases erupting into space from cracks in the moon’s icy surface. Analysis of a class of salt-rich ice grains by Cassini’s Cosmic Dust Analyzer showed the presence of sodium phosphates. The team’s observational results, together with laboratory analogue experiments, suggest that phosphorus is readily available in Enceladus’ ocean as phosphates. Phosphorus in the form of phosphates is vital for all life on Earth. It is essential for the creation of DNA and RNA, energy-carrying molecules, cell membranes, bones and teeth in people and animals, and even the sea’s microbiome of plankton. Life as we know it is simply not possible without phosphates.