World Bulletin / News Desk
The US space agency (Nasa) will make a second attempt on Tuesday to put a high-resolution carbon dioxide observatory in orbit.
Since the first satellite was destroyed on launch in 2009, scientists and engineers have built a near identical spacecraft, which will launch from the Vandenberg Air Force Base in California.
"It's been a long walk back to where we are now," David Crisp, the mission's Science Team Leader, told BBC News.
"We've delivered the spacecraft, but we've still got a number of challenging steps ahead of us before this system is on orbit, operating and returning science data."
The Orbiting Carbon Observatory-2 (OCO-2) will ride to orbit on a Delta II rocket. Lift-off is timed for a 30-second window at 02:56 local time (09:56 GMT; 10:56 BST).
The global geographic distribution of carbon dioxide in the atmosphere is going to be traced by the $468m (£275m) OCO-2 mission, to try to identify precisely where it is emitted and absorbed.
Nearly 40 billion tonnes of carbon dioxide is added to the atmosphere every year. However only half stays in the atmosphere where the other half is absorbed by the ocean and land.
It is highly uncertain exactly where though.
"Understanding what controls that variability is really crucial," said Dr Mike Gunson, the OCO-2 project scientist at Nasa's Jet Propulsion Laboratory.
"If we can do that today, it might inform us about what might happen in the future.
"Will those processes continue? Or will we see an abatement in their ability to absorb carbon dioxide, and does that increase the amount of CO2 in the atmosphere, obviously having climate change impacts."
Last Mod: 01 Temmuz 2014, 14:47