The NASA's Orbiting Carbon Observatory-2 (OCO-2) mission is seen sitting on its launch pad at Vandenberg Air Force Base in California June 30, 2014. The launch of the unmanned Delta 2 rocket from Vandenberg Air Force Base in California was called off less than a minute before lift-off on July 1 when the pad's water system failed, a live NASA Television broadcast showed. The rocket, built and flown by United Launch Alliance, a partnership of Lockheed Martin Corp and Boeing, was tentatively rescheduled to launch on Wednesday, but engineers first have to track down the cause of the water system problem, said NASA launch commentator George Diller. Picture taken June 30. REUTERS/Gene Blevins (UNITED STATES - Tags: SCIENCE TECHNOLOGY)