After several delays and two scrubbed launch attempts, NASA officials successfully launched an Earth-watching satellite early Thursday on a mission to study the planets atmosphere.

Sitting atop a 12-story Delta 2 rocket, the Aura spacecraft punched through the still-dark morning sky above Vandenberg Air Force Base in California. The on-time flight began at 6:01:59 a.m. EDT (1001:59 GMT) as Aura rose from its launch pad at Vandenbergs Space Launch Complex 2.

The Aura spacecraft is on its way to orbit the Earth it will study, said NASA launch commentator Bruce Buckingham as the spacecraft rocketed away from the California coast.

Just over an hour later, at 7:07 a.m. EDT (1107 GMT), Aura mission managers applauded and shook hands as the spacecraft separated from its booster and began its final approach into an orbit 438 miles (704 kilometers) above Earth. It was the third launch attempt in three days to loft the Earth-watching satellite and the fifth time NASA planners had scheduled the space shot within a week.

Were really looking forward to the payoffs from this mission, said Phil DeCola, NASAs program scientist, during a recent July 9 mission briefing. This mission is for the first time going to probe, in an unprecedented way, the lower part of the atmosphere.

The $785 million Aura satellite contains four instruments tucked into a 6,500-pound (2,948-kilogram) satellite the size of a school bus.

Its a really large spacecraft were bringing up there in Earth orbit, said Michael Tanner, Auras lead engineer and program executive at NASA headquarters in Washington D.C. during the mission briefing.

During its planned six-year mission, Aura will determine whether the Earths stratospheric ozone layer is recovering, study air quality and the global affects of pollution, as well as track climate change due to minute amounts of trace gases and aerosols in the atmosphere. Aura is capable of scanning the troposphere, the bottommost layer of the atmosphere in which humans live, to study the air we breathe.

Auras atmospheric observations will round out a series Earth observation missions to provide a comprehensive look at planets environment. NASAs Aqua and Terra missions - both already in orbit - are studying Earth oceans and landmasses, respectively. The Aura spacecraft is based on the design of Aqua, launch officials said.

Its great that shes going to join her sister ship Aqua up there, said a relieved Chuck Dovale, the NASA launch director who oversaw Auras liftoff.

Scrub history

Auras flight was the third launch attempt this week by NASA officials, a welcome, almost hitch-free, flight after spacecraft and rocket glitches forced two consecutive countdown aborts.

I guess the third time was a charm for Aura, Dovale said, adding that the launch team was able to solve the few technical issues that popped up during the last half hour of the countdown. We walked through a couple of hard days there and couldnt get off the ground.

Early Wednesday, launch officials called off the Aura countdown just three minutes before an attempted space shot when problems developed with the spacecrafts Boeing-built Delta 2 rocket. Battery current levels in the boosters current stage - which like the spacecraft had just been switched to internal power - were barely meeting acceptable limits, launch officials said.

An earlier Tuesday attempt was scrubbed 30 minutes before the scheduled liftoff when spacecraft engineers detected problems with Auras data recording device. The recorder, similar to data storage devices used in computers and digital camera memory cards, is responsible for storing all of the data that Aura collects during its mission. Engineers solved the problem Tuesday afternoon.

Auras launch was also delayed twice before this week, before the mission got as far as countdown operations. A July 11 liftoff was pushed back when engineers discovered a misalignment in the spacecrafts payload fairing following a July 10 delay to search Aura and its Delta 2 for suspect transistors that were found on an unrelated launch vehicle.

Dovale said NASAs next launch will take place on Aug. 2, when the Mercury probe MESSENGER is set to liftoff from Floridas Cape Canaveral Air Force Station.