The planned launch of a U.S. rocket carrying a CO2 monitoring satellite from California was called off just before liftoff on Tuesday due to a failure in the launch pad water flow, a live NASA TV broadcast showed.

The United Launch Alliance Delta 2 rocket carrying the Orbiting Carbon Observatory-2 (OCO-2) spacecraft, the first dedicated NASA mission to monitor atmospheric carbon dioxide on global scales, was supposed to be launched from the Vandenberg Air Force Base in California at 2:56 a.m. PDT Tuesday (0956 GMT).

But the launch was canceled when a failure in a Vandenberg Air Force Base Space Launch Complex 2 pad water system was discovered. The system provides sound suppression to dampen acoustic waves at liftoff and protects a launch pad flame duct.

The countdown was halted at T-46 seconds. Since the launch window was only 30 seconds, mission controllers did not have time to analyze the issue and get the rocket back on track for launch Tuesday morning.

OCO-2 has only a 30-second launch window each day. The launch window is short because the spacecraft needs to be precisely aligned within a series of Earth-observing satellites known as the "A-Train."

"It's a bit of a disappointment for the launch team when you have a great countdown up to that point," Tim Dunn, NASA launch controller said during the NASA TV broadcast.

Managers and engineers were assessing the issue to determine the cause of the failure and when they can attempt to launch OCO-2.

The OCO-2 spacecraft is on external power and the Delta II rocket first stage liquid oxygen is being offloaded. Both the spacecraft and rocket are in a safe configuration, NASA said.

The mission marks NASA's second try to measure atmospheric carbon dioxide from space. In 2009, the space agency launched the origin OCO satellite aboard a Taurus XL rocket. Shortly after liftoff, the rocket crashed into the ocean off Antarctica.

OCO-2 is dedicated to studying atmospheric carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth's climate.

According to NASA, before the Industrial Revolution, there were about 280 molecules of carbon dioxide out of every million molecules in the atmosphere, that is, 280 parts per million.

By 2014, at approximately 400 parts per million, atmospheric carbon dioxide is now at its highest level in the past 800,000 years.

The burning of fossil fuels and other human activities are currently adding nearly 40 billion tons of carbon dioxide to the atmosphere each year, producing an unprecedented buildup in this greenhouse gas.