NASA announced today that the EFT-1 mission launch has been rescheduled for 7:05 am EST on Friday. Officials at NASA, Lockheed Martin, and United Launch Alliance say the problem that finally resulted in the scrubbing of Thursday's launch of the Orion space capsule has been identified. It was a malfunction in liquid hydrogen fill and drain valves on both the port and center common booster cores used for fueling the United Launch Alliance Delta IV Heavy booster, which could not be closed properly before the launch window was exceeded.

Thursday morning's launch scrub came as a result of a series of delays due to unrelated problems. First, there were difficulties in conditioning the upper stages for flight, then a boat was reported downrange from the launch site. Following this, the winds at Space Launch Complex 37 at Cape Canaveral Air Force Station rose during sunrise to a velocity beyond safe flight parameters, which activated an automatic launch abort system.

Finally, with less than four minutes on the countdown clock, a pair of valves refused to close properly. Though engineers worked to resolve the problem in time, and mission control switched to manual override to prevent the automatic wind abort from activating too quickly, the technical problem ran out the clock for the 2-hour and 39-minute launch window, and the launch was scrubbed. Orion is currently sitting inside its gantry assembly as engineers work to fix the valve problem for Friday's attempt.

When finally launched, the Orion capsule, which is not carrying a crew, will carry out a two-orbit flight around the Earth, which will take it to an altitude of 3,600 mi (5,800 km) before returning for a splashdown in the Pacific Ocean off Baja California, where the USS Anchorage and USNS Salvor are standing by to pick it up.

The purpose of EFT-1 is to test the flight systems, computers, and other technology in anticipation of the first astronaut-carrying flight set for sometime in 2018.

NASA says that there is a 40 percent chance that weather conditions will be favorable for Friday's launch. If a second scrub is declared, NASA can still try for a Saturday morning attempt.