NASA officials delayed the scheduled launch of the Orion space capsule until Friday due to a last-minute technical problem. (Reuters)

The historic launch of Orion, NASA’s much-heralded, next-generation spacecraft, was scrubbed Thursday because of faulty valves.

The decision came after repeated delays caused by strong winds and even an errant boat that appeared to move too close to the launch site. Up until the final minutes before the close of the launch window, NASA officials held out hopes of testing the craft designed to ultimately bring humans to Mars.

But after a tense morning, several fuel and drain valves that did not function properly finally forced officials to postpone the mission. The next launch window is Friday at 7:05 a.m. EST. But officials said there was only a "40 percent chance of favorable weather conditions" for a launch Friday morning.

The uncrewed spacecraft had been scheduled to lift off at 7:05 a.m.Thursday  from Cape Canaveral, Fla., aboard a Delta IV Heavy rocket, en route to a 4.5 hour flight that would take it twice around Earth and to an altitude of 3,600 miles-- farther than any spacecraft designed for humans has traveled in more than 40 years.

As the morning unfolded, a NASA official had said on the agency's live web stream that there have been a "number of minor issues," but no "show stoppers." At one point, the official said Orion "stands ready for launch" as crews waited for the wind to die down.

In a statement, the United Launch Alliance, the joint venture between Lockheed Martin and Boeing that makes the Delta IV rocket, said that while "the liquid hydrogen fill and drain valves...did not properly close within the allotted time," the spacecraft "has no technical or operational issues and remains ready for launch."

Daniel Collins, ULA's chief operating officer, told reporters Thursday afternoon that the valves "had gotten cold and a little sluggish in their performance."

He said that the team was "listening to everything the rocket was telling us. And it told us it wasn't ready to go today. So we'll go make sure we have a happy rocket. And as soon as we do that we're going to get back to the pad and send Orion off for a very successful test flight."

 

The months-long hype and anticipation leading up to Orion's test flight reached a crescendo this week as NASA Administrator Charlie Bolden cast the launch in history-making terms, saying that "Neil Armstrong and the Apollo astronauts paved the way for this day."

Speaking on NASA TV Thursday morning, he said that "Mars is the ultimately goal for this generation."

The Orion does not have any people on board. That's not expected to happen for another seven or eight years. But the test flight will go a long way to eventually getting humans further than they've every gone before, NASA officials say. One of the key tests will be Orion's heat shield, which will face temperatures of 4,000 degrees when the capsule barrels into the atmosphere at 20,000 mph. Officials from NASA and Lockheed Martin, the massive Bethesda-based contractor that built Orion, will also be watching to see how it performs the various "separating events," and how it handles the extreme radiation of deep space.

Another key test will be the series of parachutes that deploy to slow Orion down before it splashes down in the Pacific Ocean, which is expected to occur four hours and 25 minutes after takeoff.

Mark Geyer, NASA's Orion Program Manager, said that flying the Orion without a crew would allow NASA to test the most risky systems: "We intend to stress the systems and make sure they behave as we designed them to.”

The last time a spacecraft designed for human travel left Low Earth Orbit was the 1972 Apollo 17 mission, also the last time astronauts walked on the moon. Since then, human flights have been restricted to Low Earth Orbit, home to the International Space Station. But Thursday's flight will go 15 times as far.

Sometime in the 2020s, NASA plans to capture an asteroid with a robotic spacecraft, then drag it to the moon’s orbit where it would connect with the Orion. Astronauts would then be able to take samples from the asteroid.

The big target, however, remains Mars. And Thursday’s test flight will help “put Mars within the reach of astronauts in the 2030s,” NASA says.

While the Orion was initially part of a program, called Constellation, designed to return to moon, its mission changed after the Obama administration killed Constellation and made Mars the goal. Thursday's mission would have used a Delta IV Heavy rocket, made by United launch Alliance, a joint venture of Boeing and Lockheed Martin. But future Orion missions would use the new Space Launch System rocket, which is still being developed.

Bolden has called testing Orion "a continuation of what Apollo started."

"We've taken a 40-year hiatus," he said. "And now we're back on track."

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