On Saturday, the next Mars rover will start its journey to the red planet. Only this time, NASA is sending something the size of a car. How the hell?
In the past, the rovers that NASA has sent to Mars have been fairly small. Sojourner, the first, was 65cm long and weighed 10kg. The next two, Spirit and Opportunity, were a little bigger: they were both 1.6 meters long and weighed 170kg.
But on Saturday 26 November, a new rover called Curiosity is going to be sent Mars-wards. And this plutonium-powered guy is pretty substantial. Curiosity weighs in at 900kg, and is 3 meters long. "It's the size of a Mini Cooper with the wheelbase of a Humvee," is how project scientist John Grotzinger described the new rover to the BBC. That's pretty big.
So how the hell do you safely transport something the size of a car to Mars? In the past, the rovers have floated down to the planet's surface beneath parachutes, but Curiosity is too heavy for that to work. Instead NASA has built something called a skycrane. Yes, really.
When the ship on which Curiosity is being transported reaches an altitude of 1.6km above the surface of Mars, a special descent stage with two rockets at each of its corners will separate, carrying the rover. Then, when this this secondary craft is 20 meters above the surface, the rover will be lowered using cables. When it touches down, the cables will be cut with explosives, and the secondary craft will fly off to crash land elsewhere.
Errr, at least, that's the theory. Because to me, it sounds like there's plenty that could go wrong. Also, given recent failures with craft destined to reach Mars and its surroundings, like Phobos-Grunt, there's a fairly big chance it won't even make it anywhere near.