Nasa tries again to launch new Orion spacecraft
Nasa is taking another shot at launching its new Orion spacecraft, a day after gusty wind and sticky valves held up the critical test flight.
The unmanned rocket holding Orion was poised to blast off at sunrise, although weather was threatening again to interfere.
This time, rain and clouds were in the forecast; the wind, while stiffer, was expected to blow in a more favourable direction.
Forecasters put the odds of acceptable conditions at 50-50, as a nearly full moon glowed in the sky well before dawn.
Orion will orbit the world twice on this inaugural flight so Nasa can wring out the riskiest systems before putting astronauts on board. Future missions will aim for asteroids and, ultimately, Mars.
This time, the spacecraft will shoot for a high point of 3,600 miles, farther than any spacecraft built for humans has gone since the Apollo moon programme.
The entire mission will last just 40 hours and 30 minutes, culminating with an old-style splashdown in the Pacific.
Nasa needs that extra-high altitude to gain enough momentum to re-enter at a speed of 20,000 mph and submit the capsule’s massive heat shield to 2,000 Celsius temperatures.
Thursday’s countdown paused repeatedly in the final few minutes as the wind exceeded safety limits before the valve trouble scrubbed the day’s launch.
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.
