A dramatic meteor show could hit Mars next year, astronomers have reported - and it could cause big problems for our intrepid robotic explorers in orbit around the Red Planet and on its surface.
If it comes, the frantic shower of rocks and debris will be caused by a comet -- known as C/2013 A1 (or 'Comet Siding Spring'). The comet will come as near as 89,000 kilometres to the surface of the planet in October 2014, though it might remain as far as 171,000 km away, depending on how it moves in the next twelve months. New Scientist points out that by comparison the closest a comet has come to Earth in recorded history was about 3.5 million kilometres (in 1770).
Nasa is now sure the comet won't actually hit Mars - but the effects could still be intense.
It now seems likely that Mars will be totally enveloped in the comet's coma - the cloud of material and gas which surrounds and trails the comet as it storms through the solar system - and that could lead to literally millions of small rocks and dust pouring into the atmosphere in a short space of time.
The visual effect could be dramatic and potentially very beautiful. But it could also create problems for a number of expensive and important space craft currently in orbit around Mars.
In particular, the Maven orbiter mission and India's recently-launched Mars Orbiter could be in trouble. It is also possible - though less likely - that the robotic explorers Curiosity and Opportunity could be affected too. Scientists have previously reported how most of the debris from the comet will be very small, and could take a long time to descend to the planet's surface.
Nasa's head of the Maven project told New Scientist that it is currently "in the process of defining the risk" but added that the spacecraft had been designed to be tough enough to potentially survive elements of the threat.