The maiden liftoff of a new American rocket called Vulcan Centaur has been delayed from Christmas Eve to January 8, United Launch Alliance, the company developing it, said Thursday.

The postponement stems from last-minute technical snags but ULA's CEO Tory Bruno said on X, formerly Twitter, that a recent dress rehearsal on the launch pad went well.

The rocket will be carrying a private lunar lander, developed by the startup Astrobotic, which could become the first such private craft to touch down on the moon and the first American robot to land on the surface since the Apollo program ended in 1972.

"This is sort of, in a way, the first giant step in the campaign for the US, and for all of our friends, to go back to the moon, eventually with people," Bruno told AFP in an interview last week.

"It's a pretty big deal to have a payload at all, let alone one that goes to the surface of the moon," he added.

"We wanted to do something really important and we have a lot of confidence, obviously, in the design of our rocket," Bruno said.

The asteroid and comet-hunting infrared space telescope has gathered an impressive haul of observations, but it's now at the mercy of the sun, which is accelerating its demise.

NASA's NEOWISE has had a busy decade.