Asteroid Mission Postponed

CAPE CANAVERAL, Fla. (AP) _ The planned weekend launch of a spacecraft to explore two of the solar system's largest asteroids was delayed again because of problems with a tracking ship and aircraft.

Friday, July 6th 2007, 3:15 pm

By: News On 6

CAPE CANAVERAL, Fla. (AP) _ The planned weekend launch of a spacecraft to explore two of the solar system's largest asteroids was delayed again because of problems with a tracking ship and aircraft.

NASA set Monday afternoon as a new launch time for the Dawn spacecraft, which will embark on a years-long journey to the asteroids Vesta and Ceres, which lie between Mars and Jupiter.

The spacecraft originally had been set to launch Saturday but that was nixed because thunderstorms and lightning at the launch pad prevented loading its fuel.

On Friday, the space agency called off a Sunday launch, too, because the plane used to track the spacecraft after liftoff had mechanical problems, and the tracking ship wasn't in the correct location.

Seeking clues about the birth of the solar system, Dawn will first visit Vesta, the smaller of the two bodies, four years from now. In 2015, it will meet up with Ceres, which carries the status of both asteroid and, like Pluto, dwarf planet.

NASA has until the end of October to launch the spacecraft before the planetary bodies begin to drift apart.

``After that, it becomes very problematic to do both Vesta and Ceres because they are moving apart in the sky,'' said Chris Russell, the mission's principal investigator. ``It takes about another 15 years before they get back together again.''