KYIV. June 16 (Interfax-AVN) - The second commercial launch of the private "freighter" Cygnus to the International Space Station (ISS) atop a new medium-weight launch vehicle, Antares, built in cooperation with Ukraine, has been postponed until July for technical reasons.
According to a formal statement by the United States' Orbital Sciences Corporation (NYSE:ORB), the launch of Antares with the Cignus freighter as part of the Orb-2 mission will not take place before July 1 after an investigation was extended into the AJ-26 rocket engine malfunction that occurred during its test firings as part of the launch vehicle's delivery and acceptance procedure at the J. Stennis Space Center (Mississippi, the U.S.) in late May.
The causes of the engine failure are being investigated by Aerojet Rocketdyne along with specialists from Orbital and NASA. The new date for the Orb-2 mission will be set once the investigation is complete, the statement said.
Under a $1.9 billion contract signed between Orbital and NASA in 2008, Orbital Science has until 2016 to ensure eight regular Antares flights with Cygnus to the ISS and deliver a total of 20 tonnes of supplies.
Cygnus made its first successful commercial flight to the ISS atop Antares in January 2014. The freighter delivered about 1.6 tonnes of supplies, from fresh water and foodstuffs to station maintenance parts and equipment for conducting research experiments.
The Cygnus freight module was designed and built in cooperation with the European company Thales Alenia Space. Ukraine's Yuzhnoye Design Bureau and Yuzhmash Production Association (both based in Dnipropetrovsk) designed and manufactured the first stage of Antares, which can deliver up to seven tonnes of payload to low orbits. The launch vehicle is fitted with the NK-33 rocket engine designed for the N1 super heavy rocket whose project was closed in the 1970s along with the Soviet Lunar program. Earlier the U.S. had bought about NK-33 engines from Russia.
Since 2012 flights to the ISS have also been performed by the U.S. private spacecraft Dragon. Final conclusions about the distribution of the portfolio of orders for cargo deliveries to the ISS could be made by NASA after a series of successful launches of the new launch vehicles.