Washington, Dec 10 (IANS): Orbital Sciences Corp., the private space company whose unmanned cargo rocket exploded on liftoff in late October, said it will resume cargo flights to the International Space Station (ISS) in late 2015.
The company said in a statement Tuesday that it has contracted with United Launch Alliance, a joint venture of Lockheed Martin and Boeing, for an Atlas V launch of a Cygnus cargo spacecraft from Cape Canaveral, Florida, in the fourth quarter of 2015, with an option for a second Atlas V launch in 2016 if needed.
The Atlas V rocket's greater lift capacity will allow Cygnus to carry nearly 35 percent more cargo to the ISS than previously planned for commercial resupply services (CRS) missions in 2015, Xinhua reported citing the statement.
Orbital also announced that it would accelerate the introduction of a new main propulsion system for the Antares rocket and has scheduled three additional cargo launches in the first, second and fourth quarters of 2016 using the upgraded vehicle.
The greater payload performance of the upgraded Antares will permit Cygnus spacecraft on each of these missions to deliver over 20 percent more cargo than in previous plans, said the company.
The first new propulsion systems are expected to arrive at the Antares final assembly facility at Wallops Island, Virginia, in mid-2015 to begin vehicle integration and testing, it said.
"The flexibility of Orbital's Cygnus cargo spacecraft to accommodate heavier cargo loads, together with the greater lift capacity of the Atlas V and upgraded Antares vehicles, will allow the company to complete all currently contracted ISS deliveries in four missions instead of the five previously planned flights over the next two years," Orbital said.
"In addition, the company's revised approach is not expected to create any material adverse financial impacts in 2015 or future years as Orbital carries out the CRS cargo delivery and Antares propulsion upgrade programs."
Orbital's Antares rocket exploded seconds after liftoff from the US space agency NASA's Wallops Flight Facility in eastern Virginia Oct 28. The mission would have been Orbital's third cargo flight to the ISS under a $1.9-billion contract with NASA.
A preliminary investigation into the accident pointed to "a probable turbopump-related failure" in one of the two Aerojet Rocketdyne AJ26 engines, and as a result the use of these engines has been discontinued.
The AJ26 engine is a refurbished version of the Soviet-era NK-33, which was originally designed to launch the massive Soviet N-1 rocket to the Moon.