Orbital ATK space cargo launch pushed back to tomorrow by bad weather

NASA has further pushed back the launch of commercial shipments to the International Space Station due to poor weather conditions.

The last successful U.S. supply run was in April. Russia and Japan have managed to fill the gap, but the 400-kilometre-high pantry isn't as full as it should be.

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An unmanned Atlas V rocket arrived at its launch pad Wednesday. It wasdue to lift off early Thursday evening with 3,400 kilograms of space station supplies packed into a capsule named Cygnus, after the swan constellation.

Forecasters initially put the odds of good weather at 60 per cent for Thursday's 5:55 p.m. ET launch attempt. This was later downgraded to 10 per cent and the launch time was pushed back several minutes.

The launchwas finally called off by launch director Bill Cullen when wet and cloudy weatherconditions showed no signs of improving,praisinghis team for their "great discipline."

The United Launch Alliance Atlas V rocket and Orbital ATK Cygnus spacecraft will be configured to launch Fridayat 5:33 p.m. ET. The forecast for the new launch day calls for a 30 per cent chance of acceptable conditions.

The six space station astronauts are the ultimate customers, said Frank Culbertson of shipper Orbital ATK Inc., "so we want to take them what they need."

"I'm guessing that Santa's sleigh is somewhere inside the Cygnus, and they're probably excited about their stockings coming up, too," Culbertson, president of the company's space systems group, said at a news conference Wednesday.

NASA's space station program manager, KirkShireman, said earlierthis week that without another delivery, the six astronauts' foodwould run out in April.

Orbital is launching the Cygnus from Cape Canaveral this time. Its Antares rocket is still grounded following a 2014 launch explosion that damaged the Virginia launch pad. The rocket and the company's cargo ship were destroyed.

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The Virginia-based Orbital purchased two United Launch Alliance rockets to fulfil its shipment obligations to NASA. This will be its first launch since in 2014 disaster.

NASA's other contracted shipper, SpaceX, has been grounded since a failed launch in June. The California company expects to resume deliveries in January. It had the last U.S. resupply success, back in April.

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Orbital plans another shipment via an Atlas in March, followed by the return of Antares in May with a new type of Russian-built engine. A fire and explosion in the old Russian rocket engines doomed the October 2014 flight, the company's fourth resupply mission.

Canadian content

Orbital's latest cargo ship contains food, clothes, equipment, science experiments and even storybooks, part of an astronaut-reading project for children.

Two Canadian experiments on board will look at:

• The negative impact that microgravity has on astronauts'bone marrow and blood cells, which are similar to those experienced by bedridden patients on Earth.
• Why some astronauts experience faster stiffening of their arteries in space, whichleads to high blood pressure and increased risk of cardiovascular disease. Stiffening of the arteries on Earth is linked to aging and physical inactivity.

Some of the experiments also represent redos by schoolchildren who lost their original tests on the failed launches.

Cygnuswill also carry Kaber, a device that the space station's Canadian robot Dextre will use to launch small satellites from the space station.

NASA briefly considered squeezing in a spare part to restore the space station to full power. A short circuit knocked out one of eight power channels in mid-November. Space station program manager Kirk Shireman told reporters that the astronauts first will test an old and possibly radiation-degraded spare already on board, before a replacement is put on a SpaceX Dragon capsule sometime next year.

1st space station run for Atlas

Orbital's rocket men acknowledge being a little nervous about the upcoming launch, even though the Atlas has been around for decades and is a tried and true workhorse. It typically hoists satellites for the air force and other customers; this will be its first crack at a space station run.

"You're always a little nervous, but highly confident," Mike Pinkston, general manager for the Antares, said on the eve of the launch.

Culbertson noted it's been a challenge to get to this point, "but return-to-flight became the company's very, very sharp focus" following the launch accident.

Commercial space is inevitable, NASA's Shireman stressed, failures and all. He called them "growing pains" in what still is a transition period. SpaceX opened the commercial pipeline to the space station in 2012, a year after NASA's shuttles retired.

Russia, which also experienced a failed supply mission last April before getting back on track, will launch another load of cargo in late December.

The Cygnus capsule is named after Mercury astronaut Deke Slayton, a commercial space pioneer. So was the one that was lost; this one is S.S. Deke Slayton II.