NASA preps for '7 minutes of terror' on Mars

In the wake of the wildly successful Spirit and Opportunity rover missions, you would think NASA would approach the landing of the next Martian probe with high confidence. But the truth is sometimes not what you would think.

"I do not feel confident. But in my heart I'm an optimist, and I think this is going to be a very successful mission," said principal investigator Peter Smith, an optical scientist with the University of Arizona. "The thrill of victory is so much more exciting than the agony of defeat."

Indeed, the truth is that the planetary scientists and engineers who make up the Mars Phoenix Lander team will be biting their nails Sunday evening as they cluster around computer monitors in mission control at the Jet Propulsion Laboratory in Pasadena, California.