OCO-2. Credit: Jet Propulsion Laboratory

WASHINGTON — United Launch Alliance scrubbed the July 1 predawn launch of NASA’s Orbiting Carbon Observatory (OCO)-2 satellite when water jets that protect the Delta 2 rocket’s California launchpad failed to activate in the final minute before scheduled liftoff. NASA and ULA have two more chances to launch OCO-2 before the July 4 holiday.

Facing a 30-second launch window, ULA called a hold 46 seconds before OCO-2’s scheduled 5:56 a.m. EDT liftoff from Vandenberg Air Force Base, California, after the pulse suppression system at Space Launch Complex 2 failed to deluge the pad with water at the right time, Tim Dunn, director of NASA’s Launch Services Program, said during a July 1 webcast. 

Dunn said the earliest OCO-2 could lift off is July 2. It is also possible launch could be put off until July 3. Either way, OCO-2 would again have to hit a 30-second launch window that opens at 2:56:44 a.m. local time (5:56:44 a.m. EDT). Dunn, who spoke around 6:30 a.m. EDT, said it would be “a number of hours” before crews could get to the launch pad for a closer look at the water system, which protects the launch pad from flame damage and dampens acoustic waves at liftoff.

OCO-2 was built by Orbital Sciences Corp. of Dulles, Virginia, as part of NASA’s Earth Systems Science Pathfinder program. The spacecraft’s single instrument, built by NASA’s Jet Propulsion Laboratory in Pasadena, California, is based on the three-channel spectrometer built for the original OCO satellite by Hamilton Sundstrand of Pomona, California. 

The original OCO satellite was destroyed in 2009 when the Orbital Sciences Taurus launcher crashed into the sea after a fairing separation failure. When NASA lost a second climate-observing satellite, Glory, to a similar Taurus failure in 2011, the agency yanked its OCO-2 launch contract and booked a Delta 2 as part of $412 million, three-rocket deal with ULA.

OCO-2 will measure global atmospheric carbon dioxide levels from a near-polar, sun-synchronous orbit roughly 700 kilometers above sea level. Its two-year primary mission is set to begin 45 days after launch. 

Carbon dioxide measurements made by OCO-2 will be supplemented with data gathered by aircraft and ground stations to create a global map that pinpoints locations where carbon dioxide is emitted and absorbed. NASA says the data will contribute to a better understanding of global climate change. Including spacecraft design, launch and two years of operations, OCO-2 is costing NASA $467.7 million, according to a press kit distributed online ahead of the launch. 

How NASA will continue global carbon measurements after OCO-2’s primary mission is yet to be decided. As part of the 2015 budget request unveiled in March, the White House put OCO-3, which was to be built from OCO-2 spare parts and flown as a hosted instrument on the international space station, on indefinite hold. 

For now,“[t]he current designs and OCO-2 spare hardware will be stored and held in reserve for potential future application as the measurements from the OCO-2 satellite are made and analyzed,” the White House wrote in its 2015 NASA budget request.

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Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...