NASA hopes the third time will be the charm for its OCO-2 satellite, which was rescheduled for liftoff at 2:56 a.m. Wednesday.
Tuesday's Delta II rocket launch was scrubbed Tuesday with just 46 seconds to go when a water suppression system on the launch pad at Vandenberg Air Force Base failed. OCO-2 replaces a satellite that was destroyed after a launch failure.
Watch live coverage of the OCO-2 launch
The space agency said the suppression system suffered a faulty valve during the final minutes of the launch attempt. It was replaced with a spare, and the system was being tested Tuesday in preparation for the launch attempt, NASA said in a statement.
The weather is expected to remain favorable through the 30-second launch window beginning at 2:56:23 (Pacific), NASA said.
Five years ago, the first version of the satellite burned up in Earth's atmosphere after it failed to separate from its launch vehicle, an Orbital Taurus XL. The cost of that mission was $209 million, according to a NASA investigation.
The $465-million replacement, built by Orbital Sciences Corp., would measure and map carbon dioxide in the atmosphere to provide scientists with a better understanding of how Earth's oceans, soils and forests absorb CO2 and whether that ability is changing, according to the space agency.
The satellite's nickname, OCO, comes from the scientific annotation for a carbon dioxide molecule: two oxygen atoms flanking a carbon atom in linear fashion.
The mission is managed by NASA's Jet Propulsion Laboratory in La Cañada Flintridge. United Launch Alliance of Centennial, Colorado, provided the Delta II rocket.