And the science was indeed awesome, with dozens of new discoveries generating hundreds of scientific publications. One of the primary goals of the mission was to investigate evidence that Mars once had water flowing across its surface – an element crucial for life. True to form, Oppy found that evidence almost straightaway with the discovery of the mineral hematite, which typically forms in water. The rover would go on to find further mineral evidence that Mars was once warm and wet – and had water at a neutral PH, more suitable for life – and explore sites where water once flowed.