A series of dust storms could threaten the success of three space probes heading for Mars, astronomers warn. The scientists say some small storms are combining to obscure a large part of the planet’s northern hemisphere. If they build into a global storm, which can happen, it could interfere with the solar panels the probes use to generate power for their instruments. On 25 December, Europe’s Beagle 2 will land, followed by two US rovers, Spirit and Opportunity, on 3 and 24 January.