The NASA Curiosity rover has successfully landed on the surface of Mars, helping to thrust the USA back into the space spotlight in a major way for the first time since the shuttle program ended a year ago. As usual, humor site XKCD.com hits the nail on the head:
So why did NASA need a crane? The spacecraft carrying the rover had to slow down its descent using the upward engines, but it couldn't get too low to the ground for fear of blowing dirt into the rover's sensitive machinery. Thus, NASA engineers decided to lower the actual rover from the hovering spacecraft to the surface using a crane. This is another example of the ingenuity of our space program to tackle problems that have never been dealt with before. Their creativity is astounding.
Next up: the search for signs of life! Let's go Curiosity