After a series of delays, NASA's Aura satellite (search) was launched into orbit early Thursday on a $785 million mission to study Earth's atmosphere.

A two-stage Boeing Delta II rocket (search) carrying the satellite roared off the launch pad at this Central California coastal base just before 3:02 a.m. The satellite separated from the rocket about an hour later and entered orbit 438 miles above Earth.

"Everything went well. We did get initial orbit and it seems to be right on," said Chuck Dovale, launch manager.

"I guess the third time was the charm, he said.

The liftoff was scrubbed four times in recent weeks, including twice in the past two days. Tuesday's launch was postponed because of concerns about the satellite's scientific data recorder. Wednesday's launch was scratched because of a reading of low current from a battery system on the rocket's second stage.

Dovale said three or four problems also cropped up in the 45 minutes before the launch but they were worked out without delaying the liftoff. He did not identify the problems.

NASA (search) had said there was only a 60 percent chance of launching Thursday because of concerns that the remnants of Tropical Storm Blas off Mexico might prevent the flight of a support aircraft. However, skies cleared enough for observers at the launch pad to follow the rocket on its long trajectory.

"It was spectacular. We could see it 150 miles away," NASA spokeswoman Lynn Chandler said. "It was just stars and very few clouds."

Aura's six-year mission is intended to determine the composition of Earth's atmosphere in unprecedented detail.

"We're really looking forward to the payoffs, both in terms of scientific understanding and benefits to society that are going to come from this Aura mission," program scientist Phil DeCola said last week.

The mission seeks to improve understanding of how pollutants spread globally, to determine whether the stratospheric ozone layer, which blocks harmful ultraviolet radiation, is recovering from depletion by manmade chemicals, and how Earth's climate is the changing as its atmosphere is altered.

The 6,542-pound satellite carries four instruments, built by Great Britain, the United States, the Netherlands and Finland.

Science operations were slated to begin about 90 days after launch.

Aura, managed by the Goddard Space Flight Center (search) in Greenbelt, Md., is part of NASA's first series of Earth Observing System satellites. Two other parts of the system are already in orbit: the Terra satellite, which observes land, and Aqua, which studies Earth's water cycle.