By Irene Klotz
CAPE CANAVERAL, Fla. (Reuters) - A year after its Antares rocket exploded during launch, Orbital ATK is poised to resume cargo runs to the International Space Station, this time using a hired ride from United Launch Alliance, a Lockheed Martin Corp and Boeing Co joint venture.
Liftoff of the ULA Atlas 5 rocket is slated for 5:55 p.m. EST (2255 GMT) on Thursday from Cape Canaveral Air Force Station in Florida.
Perched on top of the rocket is Orbital’s fourth Cygnus spacecraft, an upgraded capsule filled with more than 7,700 pounds (3,500 kg) of food, supplies and science experiments for the station.
"This is step one in the return-to-flight plan," said Mike Pinkston, Orbital’s Antares program manager. Orbital expects to start using its own Antares rocket in May 2016.
Dulles, Virginia-based Orbital had completed a test flight and two of its originally planned nine station cargo runs under a $1.9 billion contract with NASA, delivering about 8,400 pounds (3,800 kg) pounds of a promised 22 tons of supplies, when Antares faltered on Oct. 28, 2014.
Investigators blamed the botched launch on a defective turbopump in one of Antares’ two main engines, a Soviet-era motor refurbished and sold by Aerojet Rocketdyne Holdings . Exactly what went wrong remains a matter of debate, but Aerojet paid Orbital $50 million to settle the dispute and the companies ended their collaboration.
Orbital, which already had planned to outfit Antares with new engines, grounded the rocket and quickly settled on a new supplier, Russia’s NPO Energomash, the same company that supplies the RD-180 engines that power ULA’s Atlas rocket.
Ukraine-related trade sanctions enacted last year ban U.S. military use of the RD-180 engines. The ban does not affect commercial and civilian government customers like the U.S. space agency, but it will keep Orbital from offering Antares as launcher for U.S. military satellites.
Orbital, which competes against privately-owned Space Exploration Technologies, or SpaceX, and Sierra Nevada Corp for follow-on cargo delivery contracts, is counting on ULA’s Atlas rocket to send its next two Cygnus capsules to the station, a $100 billion laboratory that flies about 250 miles (400 km) above Earth.
Resupplying the station has been a challenge for NASA, following not only Orbital’s accident, but the loss of a Russian Progress ship in April and a SpaceX Dragon capsule in June.
(Reporting by Irene Klotz; Editing by Tom Brown)