NASA launch exploration module Orion into space

NASA’s unmanned Orion space capsule has splashed down in the Pacific Ocean off Baja California following its first successful flight test.

Blast off ... the NASA Orion space capsule atop a Delta IV rocket lifts off from Cape Canaveral. Picture: John Raoux/AP

NASA’s unmanned Orion space capsule has splashed down in the Pacific Ocean off Baja California following its first flight test, the US space agency says.

“There is your new spacecraft, America,” NASA commentator Rob Navias said, as live aerial images showed the capsule floating toward the water aided by three parachutes.

Orion splashed down in the Pacific four hours and 24 minutes after launch from Cape Canaveral, Florida on Friday, NASA said.

Splash down ... the Orion capsule floats after splashing down in the Pacific Ocean after a dramatic test flight. Picture: AP Photo/NASA-TV

Amazing visuals of #Orion's return from @NASAArmstrong Ikhana aircraft. pic.twitter.com/psYbvyxvxP

— Orion Spacecraft (@NASA_Orion) December 5, 2014

Navias described the test flight as “picture-perfect” and “a significant milestone for America’s space program”.

Flight controllers said the vehicle was in stable condition and would soon be retrieved from the waters by a team that includes NASA, the US Navy and Lockheed Martin.

The unmanned rocket holding Orion blasted off on Friday at sunrise US time (11pm Australian Eastern Time), lighting up the skies as it launched from Cape Canaveral atop a Delta IV Heavy rocket.

Space bound ... Orion is rocketed into space. Picture: Bruce Weaver/AFP

No astronauts were on board the capsule for the four-and-a-half hour flight carried the spacecraft around the Earth twice before splashing down in the Pacific Ocean.

NASA hopes to wring out the riskiest systems before putting astronauts on board.

Future missions will aim for asteroids and, ultimately, Mars.

This time, the spacecraft shot for a high point of 5800km, farther than any spacecraft built for humans has gone since the Apollo moon program.

Dizzy heights ... a view from the Orion spacecraft atop a United Launch Alliance Delta 4-Heavy rocket as it climbs to orbit. Picture: NASA-TV/AP

NASA needed that extra-high altitude to gain enough momentum to re-enter at a speed of 32,000km/h and submit the capsule’s massive heat shield to 4000-degree temperatures.

The launch was scheduled on Thursday but had to be scrapped as the wind exceeded safety limits before the craft experienced valve trouble.

Engineers spent the remainder of the day trying to understand why two fuel valves in the first-stage booster engines behaved so sluggishly.

The problem had been detected before on another rocket and officials were confident it could be overcome.

Jubilation ... NASA astronauts (from left) Rex Walheim, Jack Fischer and Cady Coleman, cheer as they watch the landing of the Orion test flight at the Kennedy Space Centre. Picture: AP

Capturing history ... onlookers see the moment of take off. Picture: Joe Raedle/Getty Images

Lockheed Martin Corp, which conducted the $US370 million test flight for NASA, opted for the Delta IV rocket this time given its heft.

It’s the most powerful unmanned rocket in the US right now. To push Orion farther out on future flights, NASA is developing a megarocket known as Space Launch System or SLS.

The first Orion-SLS combo will fly around 2018, again without a crew. Astronauts are expected to climb aboard in 2021.