When you've got a landing sequence as complicated as the Curiosity's and seven or so minutes of radio delay, there are plenty of things that can go horribly wrong. Fortunately, the folks at mission control have secret insurance up their sleeves: peanuts.
Having peanuts present during times of extreme stress has become something of a tradition in the NASA control room, and with a $2.6 billion rover and mission on the line, it'd be a bad time to stop being superstitious.
NASA put it this way:
Good-luck peanuts made their first appearance in 1964 during the Ranger 7 mission. JPL had six failures prior to this effort. The Ranger 7 launch day arrived and with it came the peanuts. The mission performed flawlessly, as did its peanut-powered successors, Ranger's 8 and 9. Up until the Voyager mission, peanuts showed up only at launch. Nowadays, they are often seen in mission control facilities during critical mission stages such as orbit insertions, flybys and landings, or any other event of high anxiety or risk.
But you don't have to take their word for it. Go explore this panorama of the NASA control room for a bit, and you'll see there is no shortage of peanuts. That alone means the rover is sure to touch down without a hitch. That's how cause and effect works, right? [Business Insider]