After a almost two-month delay, the rocket is set to blast off sometime during a two-hour launch window, which opens at 8 p.m.
About 8 minutes later, the first stage of the Falcon 9 rocket came in for a lovely night landing at a launch pad back at the Cape. The company has said it plans to launch roughly 30 missions in 2018 after completing a record 18 a year ago.
This will be SpaceX's first launch of 2018.
An undisclosed issue with the Falcon 9 rocket's fairing caused SpaceX to delay the launch for several weeks in November and eventually move the date forward to January 4.
Elon Musk's Space Exploration Technologies Corp successfully launched its first mission of the new year: a classified payload for the USA government into low-earth orbit.
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But now conditions for the mysterious mission are 80-percent go, weather-wise, in Florida. (SpaceX has had 17 consecutive successful landings, so they're getting pretty good at this).
The payload will be delivered to low Earth orbit, per the mission parameters, but we don't know anything else about its objective, design, or intended mission, because it's all classified. But Sunday's launch is perhaps the company's most secretive yet.
SpaceX's top secret launch, code-named Zuma, is set for Sunday night, according to officials with the company.
SpaceX and the Pentagon did not respond to requests for comment about the nature of the mission.
It's SpaceX's third classified launch for the USA government, this one taking place under a deal with defense contractor Northrop Grumman.