A rocket made almost entirely of 3D-printed parts has made its launch debut, lifting off amid fanfare but failing three minutes into flight, far short of its intended orbit.

There was nothing aboard Relativity Space's test flight, except for the company's first metal 3D print made six years ago.

The startup wanted to put the souvenir into a 200-kilometre-high orbit for several days before having it plunge through the atmosphere and burn up along with the upper stage of the rocket.

As it turned out, the first stage did its job after lift-off from Cape Canaveral Space Force Station and separated as planned.

However, the upper stage appeared to ignite and then shut down, sending it crashing into the Atlantic.

It was the third launch attempt from what once was a missile site.

Relativity Space came within a half-second of blasting off earlier this month, with the rocket's engines igniting before abruptly shutting down.

Although the upper stage malfunctioned and the mission did not reach orbit, "maiden launches are always exciting and today's flight was no exception", Relativity Space launch commentator Arwa Tizani Kelly said after the launch.

"We also progressed through Main Engine Cut-off and Stage Separation.

"We will assess flight data and provide public updates over the coming days."

Most of the 33-metre-tall rocket, including its engines, came out of the company's huge 3D printers in Long Beach, California.

Relativity Space said 3D-printed metal parts made up 85 per cent of the rocket, named Terran.

Larger versions of the rocket will have even a higher percentage and also be reusable for multiple flights.

Other space companies also rely on 3D-printing, but the pieces make up only a small part of their rockets.

Founded in 2015 by a pair of young aerospace engineers, Relativity Space has attracted the attention of investors and venture capitalists.

AP