A couple of hours ago, I watched the New Horizons probe to the planet Pluto blast off on an Atlas V rocket. It was quite an impressive launch, with a 200-foot-tall rocket loaded with several hundred thousand pounds of liquid fuel needed to loft the piano-sized, 1000-pound probe into space.
Several news organizations were playing up the three-day delay in the rocket launch. This is unfair, in my opinion, because these rockets are extremely complex. If the weather is bad or the electricity is out (the causes of the delay), you risk the entire mission. In this case, it isn't only a few hundred million dollars down the tubes, but also there would be the added risk of spreading radioactive material along the eastern seaboard of the United States. Also, you are trying to hit a target smaller than the moon from a distance of 4 billion miles, so you can imagine that the constraints are pretty tight!
But, New Horizons is on its way; here's hoping for a successful mission to the outer solar system!