Antares launch
Orbital ATK’s Antares rocket lifts off from NASA’s Wallops Flight Facility in Virginia. (Credit: NASA TV)

Orbital ATK’s Antares two-stage rocket sent a robotic Cygnus cargo spaceship on its way to the International Space Station today, nearly two years after a launch pad failure forced an engine overhaul.

The Antares rocket blasted off from NASA’s Wallops Fllight Facility in Virginia right on time, at 7:45 p.m. ET (4:45 p.m. PT). NASA said the launch could have been seen by skywatchers across a wide swath of the East Coast, weather permitting.

Ten minutes after launch, the cylindrical Cygnus craft separated from the second stage, heading for the station with 5,100 pounds of supplies. After a series of checkouts, the Cygnus will approach the station for a rendezvous on Sunday.

This was the first Antares launch since October 2014, when the rocket and its payload blew up just seconds after liftoff. The failure was traced to a turbopump failure in one of the Antares’ refurbished 40-year-old Russian engines. In order to return to flight, Orbital ATK had to replace Antares’ engines with upgraded RD-181 engines from Russia. Wallops’ Pad-0A also had to be repaired.

In the meantime, Orbital ATK launched two Cygnus ships on space station resupply missions from Florida late last year and early this year, using United Launch Alliance’s Atlas 5 rockets.

In addition to food, water and other necessities for the space station’s crew, Cygnus is carrying an array of scientific experiments, including a system to study how flames burn in the zero-gravity environment and a Fast Neutron Spectrometer to register high-energy particles hitting the space station.

Once the Cygnus arrives at the station, astronauts will unload the cargo and fill the spacecraft with trash. In November, the Cygnus will be set loose to descend through the atmosphere and burn up.

Virginia-based Orbital ATK is resupplying the space station under a multibillion-dollar contract with NASA. SpaceX is also under contract for resupply missions, but that company has suspended launches of its Falcon 9 rocket due to the investigation of a satellite launch failure last month. Russia’s Progress space capsule and Japan’s H-II Transfer Vehicle are also used for space station resupply.

Update for 1:30 a.m. PT Oct. 24: As expected, the Cygnus was successfully pulled in for its berthing to the station at 7:53 a.m. PT Oct. 23, and its cargo will be unloaded over the next few weeks.

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