The U.S. government’s mysterious Zuma spacecraft, whose launch was postponed from November, is now slated to lift off Jan. 5, according to SpaceX.

The Falcon 9 rocket that will carry Zuma to low Earth orbit underwent a propellant loading test Jan. 3 on its launch pad at NASA’s Kennedy Space Center in Florida, SpaceX tweeted.

SpaceX's Falcon 9 rocket launches June 28, 2015, at Cape Canaveral Air Force Station, Fla. Photo: NASA.
SpaceX’s Falcon 9 rocket launches June 28, 2015, at Cape Canaveral Air Force Station, Fla. Photo: NASA.

Zuma was supposed to be launched Nov. 16 but was delayed because SpaceX said it wanted to “take a closer look at data from recent fairing testing for another customer.” The company did not elaborate.

Northrop Grumman [NOC] has said that it acquired the launch service for the U.S. government, but it has declined to identify the specific agency or the spacecraft’s mission.

Also on Jan. 3, SpaceX tweeted more photos of its new Falcon Heavy rocket on a launch pad at Kennedy. The rocket’s first flight test is slated for later this month.

SpaceX says that Falcon Heavy could eventually carry people to the moon or Mars and will lift more than twice the payload of its closest competitor, the United Launch Alliance (ULA) Delta 4 Heavy. The Falcon Heavy uses the same Merlin first-stage engine as the Falcon 9 but triples the number of those engines to 27.

Other launches planned for this month include the Air Force’s fourth Space Based Infrared System (SBIRS) geosynchronous Earth orbit (GEO Flight-4) missile-warning satellite, which will ride Jan. 18 on a ULA Atlas 5 from Cape Canaveral Air Force Station in Florida. On Jan. 10, a Delta 4 is supposed to carry a National Reconnaissance Office satellite (NROL-47) from Vandenberg Air Force Base in California.