Lab notes: Toxic Mars, mission to Mercury and string theory

Remember Matt Damon growing potatoes from his own waste in Ridley Scott's spectacular man-on-Mars space epic The Martian? Of course you do. Damon's botanist astronaut Mark Watney devises an ingenious way of surviving four years till his only chance of being rescued when another mission flies by Mars. So he grows spuds and lives to tell the tale - in the film, that is. In reality, Mr Watney wouldn't have stood a chance as Martian soil, as experiments revealed this week, contains a cocktail of toxic chemicals potent enough to smother anything remotely living. The planet gets cooked in ultra violet light that renders it's surface toxic and sterile, so search for alien life - microbes, at best - have to dig deep underground.

From Mars we move to Mercury - its strange orbit played a key role in overthrowing of Newtonian physics by Einstein's theory of general relativity that correctly predicted a slightly rosette-like orbit instead of perfectly elliptical. But it isn't just about the orbit - almost sun-kissed, the solar system's smallest and innermost planet also appears to be shrinking. That and its other mysterious properties will be probed by the European Space Agency's third mission to Mercury as it prepares to launch BepiColombo spacecraft - a joint venture with Japan's space agency Jaxa - in October 2018. To understand why the task is extra complicated and how the ESA plans to overcome the incredibly difficult engineering problems of manoeuvring the spacecraft under scorching temperatures read Stuart Clark's insightful piece from mission HQ in Noordwijk, near Amsterdam.