Atlas V takes Orbital ATK capsule toward space station

The United Launch Alliance Atlas V rocket stands ready for a launch attempt Friday, Dec. 4, 2015, at launch complex 41 at the Cape Canaveral Air Force Station, Fla.

The launch of the privately developed Orbital ATK Cygnus spacecraft began the company’s fourth operational cargo resupply mission, named CRS-4, under a commercial resupply services (CRS) contract to NASA.

On Sunday, private spaceflight company Orbital ATK returned its Cygnus cargo ship to flight with a superb afternoon launch after a year’s gap. NASA’s other commercial supplier, SpaceX, is also stuck on Earth.

The Falcon 9’s last flight in June ended in failure while carrying a Dragon capsule full of ISS supplies.

The precious cargo inside the Orbital ATK’s Cygnus spacecraft is filled with mre than 7,000 pounds of food, equipment and scientific experiments for the six astronauts aboard the orbiting space laboratory. Cygnus will remain attached to the station for approximately 50 days before departing with roughly 5,050 pounds (2,300 kilograms) of disposable cargo for a safe, destructive reentry over the Pacific Ocean.

Before fueling the rocket for a 5:10 p.m. launch attempt, managers may opt to wait until Sunday for slightly better weather.

Dubbed the SS Deke Slayton II, Cygnus was released from the rocket 21 minutes after liftoff and became an autonomous, free-flying spacecraft. Russia, which also lost a shipment earlier this year, has another supply run coming up in two weeks.

This is the first time a Cygnus is launching on an United Launch Alliance Atlas V rocket, and the first time it’s launching out of Cape Canaveral in Florida. Today, the station has enough food and supplies to last until April, which is below the six month margin of NASA.

The launch drew more attention than normal for station resupply missions because of several recent failures.

Orbital ATK’s composite structures and solid rocket motors also supported today’s launch of the ULA Atlas V rocket.

Over the course of the successful first two flights in Orbital ATK’s $1.9 billion, eight-flight contract with NASA, the company’s Cygnus vehicles have delivered more than 7,940 lbs. The payload, packed in Orbital’s Cygnus cargo craft, is to rendezvous with the space station on Wednesday.

United Launch Alliance builds and flies the powerful Atlas V, a workhorse normally used to hoist satellites for the Air Force and others.

Its third cargo mission was destroyed in a launch explosion in October past year.