WASHINGTON — After sending its Falcon 9 v1.1 rocket to the hangar for engine inspections and a gas-generator swap, Space Exploration Technologies Corp. (SpaceX) will make its third attempt to launch its first commercial communications satellite — SES-8 — on Dec. 3.

An hour-long launch window opens at 5:41 p.m. Eastern time.

“We’re now targeting launch on Tuesday with Wednesday as a back-up day,” SpaceX spokeswoman Emily Shanklin wrote in a Dec. 2 email. 

“All known rocket anomalies resolved,” SpaceX founder and Chief Executive Elon Musk tweeted Dec. 2. SpaceX crews at the Cape Canaveral Air Force Station in Florida “[w]ill spend another day rechecking to be sure.”

SpaceX tried twice to launch SES-8, which belongs to satellite fleet operator SES of Luxembourg, on Nov. 28. The Hawthorne, Calif.-based company aborted the first attempt just after ignition because of a slower-than-expected pressure ramp-up in the Merlin 1-D engines that power its Falcon 9 v1.1 rocket.

A second attempt later that evening was aborted with less than a minute to go in the countdown because of oxygen contamination in the ground-based chemical igniter used to light the engines, Musk tweeted Dec. 1.

The rocket was taken off the pad so that the interior of its engines could be examined with a borescope. Following the inspection, SpaceX opted to replace the gas generator that powers one of the rocket’s nine Merlin 1-Ds “as a precautionary measure,” Musk tweeted.

A successful SES-8 launch would set the stage for SpaceX to begin clearing out a big backlog of commercial satellite launch contracts the company won well in advance of completing the Falcon 9 v1.1 rocket.

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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...