The Persian cat and a Norway rat had an eschat chat with a faithless fruit bat...

NASA's Dawn mission has finally made it to the launch pad. The mission was originally scheduled to take off in July but was postponed so NASA could give 100% attention to the recently completed STS-118 mission to the ISS. A Delta II 7925-H (heavy lifter) has made it to launch pad 17-B and the Dawn payload is atop of it. The mission's launch window starts September 26th and closes October 15th...the next Shuttle missioon STS-120 is slated for an October launch. The Dawn spacecraft will zoom off to the asteroid belt to study two of the largest objects orbiting there, Ceres and Vesta.

Ceres has a spherical body about the size of Texas and was recently dubbed a dwarf planet, in the same recatagorizing that eliminated Pluto from the classification as an outer planet. Vesta was the fourth object discovered in the belt and is about the size of Arizona. Scientists estimate Ceres could be composed of up to 25% water, which takes form as ice buried under a surface of space dust, and could quite possibly have polar ice caps...on the other side of the spectrum Vesta appears to be composed of basalt rock, frozen lava which would indicate resurfacing and an early history of volcanism. Vesta is nearly spheroid in shape except for a huge impact crater at it's south pole. It is estimated that about 5% of the meteorites found on Earth originate from a massive impact in the asteroid belt, much like the one that ejected debris out of Vesta's crater.

The Asteroid Belt orbits the Sun in between the orbital paths of Mars and Jupiter. The four largest objects in the belt, including the two listed above and Pallas and Hygiea comprise almost half of the overall mass of the main belt. The rest of the objects range in sizes from a grain of sand to a mountain.

The Dawn spacecraft is scheduled to reach Vesta in September 2011 and study the asteroid until April 2012...at that point it will make it's way to Ceres by February 2015, with the primary mission coming to an end in July 2015. I would assume that like most successful NASA exploration missions, Dawn will continue on much longer than the projected timeframe.

-A