Moment of truth awaits Europe's Schiaparelli Mars probe

The European Space Agency (Esa) is getting ready to put a probe on Mars. Its Schiaparelli robot will attempt the risky descent to the surface in the coming hours, after a 500 million km journey from Earth. The touchdown is regarded as a dress rehearsal for a much more important venture in four years' time when Esa will bid to place a very expensive rover on the planet. This six-wheeled vehicle will drill beneath the surface to search for life. Getting the smaller Schiaparelli robot down ought to be the simpler affair.