Today, Elon Musk's SpaceX will launch "Zuma", a mysterious government spacecraft of unknown goal, on one of its partially-reusable Falcon 9 two-stage rockets from Launch Complex 40 at Florida's Cape Canaveral Air Force Station.
The launch window opens at 8 p.m. and closes at 10 p.m.
The deployment of the satellite was followed by the successful landing of the Falcon 9 first stage at the nearby landing zone at Cape Canaveral Air Force Station. The launch was originally scheduled for November 2017, but the mission was delayed so SpaceX could review data from a fairing test. Few details have been released about the classified mission, known as Zuma, other than it includes a satellite built by Northrop Grumman Corp.
The booster's two stages separated 2 minutes and 19 seconds into flight.More news: Kadri tugs at Thornton's beard, Maple Leafs beat Sharks
After launch, SpaceX returned the tall portion of the Falcon 9 rocket to an upright landing at Cape Canaveral.
SpaceX is slated to launch the top-secret government mission Zuma from Cape Canaveral Sunday night. But Sunday's launch is perhaps the company's most secretive yet.
SpaceX and the Pentagon did not respond to requests for comment about the nature of the mission.
Defence contractor Northrop Grumman Corp was assigned to choose which company would launch the restricted payload, and it selected SpaceX's Falcon 9, calling it a cost effective option, said Lon Rains, a Northrop Grumman spokesman, before the launch.