NASA launched its first mission to the planet Mercury in a generation early on today, one that scientists hope will strip away much of the mystery surrounding the tiny planet closest to the sun.
The MESSENGER spacecraft, riding a Boeing Delta 2 rocket, blazed across the nighttime sky above Florida's Cape Canaveral Air Force Station as the $427 million mission got under way with lift off at 7:16 Irish time.
Among the questions scientists hope to answer is whether Mercury, just slightly larger than Earth's moon, was once Earth-sized itself but lost its rocky exterior either to some cataclysmic collision or to slow ablation by the solar winds.
Scientists also believe there may be frozen water there, trapped in shadowy craters at the planet's poles, never exposed to the sunlight that creates a 1,100 degree F difference between daytime and nighttime temperatures on the planet.
MESSENGER will reach Mercury after a seven-year journey through the solar system that will take it 15 times around the sun, making near passes of Earth once, Venus twice, and Mercury itself three times.