SpaceX's Falcon 9 rocket -- last seen plummeting toward earth before making a dramatic upright landing -- is ready to fly again.

CEO Elon Musk said the rocket was undamaged during its launch and subsequent return to earth on December 21.

"Falcon 9 back in the hangar at Cape Canaveral." Musk said on Instagram. "No damage found, ready to fire again."

The Falcon 9's flight was a remarkable technical breakthrough. Once the rocket's second stage engines ignited, the booster stage engines detached. It then executed a series of fuel burns to position itself for a gentle, upright landing near Cape Canaveral in Florida.

Falcon 9 back in the hangar at Cape Canaveral. No damage found, ready to fire again. A photo posted by Elon Musk (@elonmusk) on Dec 31, 2015 at 4:18pm PST

Landing rockets upright is crucial to cutting the cost of space travel, since the rockets can be reused. Most rockets that have carried people or satellites to outer space over the past 58 years have been discarded after their launch, often burning up upon reentry.

Space X has said it will carry out tests on the returned rocket to test its condition.