After several delays, NASA's Aura satellite was successfully launched into orbit early Thursday for a study of Earth's atmosphere.

The Aura, built for NASA by Northrop Grumman Corp., was launched aboard a Boeing Co. Delta II rocket from Vandenberg Air Force Base at 6:02 a.m. EDT (1002 GMT). It entered orbit 705 km above Earth.

Technical problems including concerns about Aura's scientific data recorder and the rocket's battery system have postponed the spacecraft's launch four times in recent weeks, including twice in the past two days.

The six-year, US$785 million mission is planned to determine the composition of Earth's atmosphere in unprecedented detail. Among its tasks, Aura will gather data on damages in the ozone layer and track pollutants.

Aura is a part of NASA's first series of Earth Observing System satellites. Two other parts of the system are already in orbit: the Terra satellite, for the observation of land, and Aqua, for the study of water.

(Xinhua News Agency July 16, 2004)