The assault on Mars by ESA's Mars Express orbiter and Beagle 2 lander and NASA's two Mars Exploration Rovers is being threatened by a dust storm in Mars' northern hemisphere, which may expand to global proportions. Mars Express's view of the surface may be impeded during the first weeks of operations, while winds could disrupt the landings of the three other spacecraft. Even if they land successfully, dust could coat the solar panels reducing power and could invade other critical systems, in addition to spoiling images.

In November 1971, three spacecraft were affected to varying degrees by a global dust storm. The Soviet Union's Mars 2 and 3 orbiters had their views impeded, while the views from NASA's Mariner 9 - the first Martian orbiter - were restricted until January 1972 by storms. The storms may also have caused the Mars 2 and 3 landing capsules to fail. Mars 2 crashed, while Mars 3 may have landed - before NASA's Viking 1 in 1976 - but 20s of television signals showed no contrast and then stopped.

Source: Flight International