No, really: is there life on Mars?

As Bowie tributes go, it’s extravagant: this Monday, the European Space Agency will launch the Trace Gas Orbiter on a seven-month mission to answer his enduring question: is there life on Mars? Or, as the ESA rather more scientifically puts it, “to search for evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes.” It’s a triumph for scientists who’ve overcome 11 years of technological, political and financial problems since the mission was first approved back in 2005. So much for a god-awful small affair.