WHEN can we declare the Red Planet a dead planet? Although most efforts so far have gone toward showing that other planets could support life, now is the time to think about the other side of the coin. Spacecraft going to other worlds must follow costly planetary protection protocols, such as sterilisation, to avoid contaminating their destination with Earth microbes, putting any native life at risk, or bringing potentially dangerous alien ones back. But if there’s nothing there, why bother? We haven’t found life on Mars yet, and if further missions also turn up nothing, at some point commercial space...
