Update for 2 pm ET: NASA's first Orion test flight has been a stunning success. Read our mission wrap story here:Splashdown! NASA's Orion Spaceship Survives Epic Test Flight as New Era Begins

CAPE CANAVERAL, Fla. It's the test flight NASA has been waiting for. After a scrapped launch attempt Thursday (Dec. 4), NASA's new Orion capsule, designed to help deliver humans to deep space destinations like Mars someday, has just launched on its rigorous first test flight.

A United Launch Alliance Delta 4 Heavy rocket (the most powerful rocket currently flying from Earth) roared to life, launching the unmanned Orion space capsule from a pad here at Cape Canaveral Air Force Station at 7:05 a.m. EST (1205 GMT) today (Dec. 5). The prototype spacecraft is now embarking on a series of tests in orbit before its planned splashdown in the Pacific Ocean at about 11:30 a.m. EST (1630 GMT), 4.5 hours after leaving the planet. You can continue watching live coverage of the Orion test on Space.com, courtesy of NASA TV.

"We're actually excited about this particular step on our journey to the Red Planet, to Mars," NASA administrator Charles Bolden told members of the press Wednesday (Dec. 3), before launch. "It is a journey. I don't want people to get focused on the destination. This is a journey." [NASA's Orion Test Flight: Full Coverage]

This morning's launch was originally scheduled for 24 hours earlier, but several issues including a boat downrange of Cape Canaveral, strong ground-level winds and the failure of several "fill and drain" valves on the Delta 4 Heavy to close all the way pushed things back a day.

Today's flight, called Exploration Flight Test-1 (EFT-1), marks the first time a spacecraft built for humans will travel out of low-Earth orbit in more than 40 years, and the excitement about the history-making flight is palpable at Kennedy Space Center, which is next door to Cape Canaveral.

About 27,000 spectators were expected to watch the launch Thursday from the NASA center's grounds, with thousands more expected to observe from the beaches and other viewing sites along Florida's Space Coast here, NASA officials said. Officials aren't yet sure how many viewers came back for the launch Friday.

"The launch itself was just a blast to see how well the rocket did," Mark Geyer, NASA's Orion program manager, said after launch. "It was exciting to see it as it went up into space. Being here at launch, being near a rocket that big, you just kind of feel it."

Orion built for NASA by Lockheed Martin, which is overseeing today's flight looks somewhat like the capsules flown during NASA's Apollo moon landing program, which took humans to the moon for the first time. The feeling on the ground is also somewhat reminiscent of launches during the space agency's shuttle era, the last time humans flew to space from U.S. soil.

"In the sense that we are beginning a new mission, it is, I think, consistent with the beginning of [the space] shuttle [program], the beginning of Apollo," Geyer said during a news conference before launch. "It's a new mission for us starting in the region of the moon and beyond. I think it's in that same category. Certainly the team is excited at that level. We're going to learn a lot on this flight."

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