NASA says rocket launch team will try again tomorrow after 2 days of weather delays

Poor wind conditions grounded a critical space station delivery for NASA on Friday, the second day in a row the rocket launch has been delayed by weather.

An unmanned Atlas rocket was poised to lift off at sunset with about 3,550 kilogramsof supplies for the International Space Station.

• Bad weather further delays U.S. space station cargo shipment
• Spaceflight disasters show it's still 'very hard' to get into orbit
• Antares rocket explosion: Will it set back the commercialization of space?

Thursday's launch attempt was rained out. Early Friday afternoon, the forecast improved slightly, but forecasters still had concerns about thick clouds ahead of the planned 5:33 p.m. ET liftoff.

The launch time was further pushed back later that day to 6:03p.m. ET, the end of the 30-minute launch window, due to ground winds exceeding acceptable limits.

The ground-wind violation held the countdown outside the launch window, cancelling the launch for Friday.

"The winds were just a couple of knots too high, so we just didn't feel comfortable launching tonight," said Vernon Thorp of United Launch Alliance.

"It appears that maybe Mother Nature has played tricks on us once again," saidNASA launch commentator Mike Curie.

The launch team reset the liftoff for Dec. 5 at 5:10 p.m. ET, but forecasters have put the odds of acceptable weather conditions for launch at 30 per cent.

The six space station astronauts have gone without U.S. shipments since April. Two private companies contracted by NASA to replenish the orbiting lab are stuck on Earth with grounded rockets. Orbital ATK bought another company's rocket, the Atlas, for this supply mission.

Rocket packed with food, supplies

Orbital's last grocery run ended in flames seconds after liftoff last year. SpaceX, the other supplier, suffered a launch failure in June.

Russia also lost a supply ship earlier this year. But it's since picked up the slack, along with Japan. A Russian resupply mission, in fact, is scheduled just before Christmas.

Much-needed food is inside Orbital's cargo carrier, named Cygnus after the swan constellation. NASA normally likes to have a six-month stash of food aboard the space station, but it's down a couple months because of the three failed flights. Space station program manager Kirk Shireman expects it will take another year to get the pantry full again provided there are no more accidents.

Also aboard the newest Cygnus capsule: clothes, toiletries, spacewalking gear, air-supply tanks and science experiments.

Orbital plans to launch another of United Launch Alliance's Atlas rockets in March, then return its own Antares rocket to flight from Virginia in May. SpaceX, meanwhile, aims to restart station deliveries in January with its Falcon rockets.