On Oct. 28, the Antares rocket of Orbital Sciences exploded just seconds after it took off in its second attempt to carry the Cygnus cargo ship bound for the International Space Station (ISS). Now, the Virginia-based company said that the rocket's Russian first-stage engines may be to blame for the mishap.
Orbital Sciences said on Nov. 5 that the probe on the explosion of the Antares is looking at the Aerojet Rocketdyne AJ26, which were built by the Russians in the 1960s at the peak of the space race.
Orbital Sciences president David Thompson said that while the results of the investigation are still preliminary and are subject to change, there is strong evidence suggesting that one of the two AJ26 main engines that powered the first stage failed a few seconds after ignition.
"At this time, we believe the failure likely originated in, or directly affected, the turbopump machinery of this engine, but I want to stress that more analysis will be required to confirm that this finding is correct," Thompson said.
Originally named NK-33, the AJ26 engines were built by the Kuznetsov Design Bureau for the Russian NI rocket, which was part of Soviet Union's ill-fated attempt to land on the moon. The engines were ordered destroyed after the project was halted but an enterprising bureaucrat kept the engines safe.
Decades later, some of the engines made their way into the hands of GenCorp Inc.'s Aerojet Rocketdyne, which refurbished and renamed the engines.
Orbital Sciences already had plans to replace the Russian-made engines by 2017 but the upgrade will now likely occur earlier after the incident.
The company says that it is planning to enhance its rocket propulsion system in 2016, which will enable it to fulfill its obligation in the $1.9 billion contract it has with the National Aeronautics and Space Administration (NASA) for resupply missions to the ISS.
"We will likely discontinue the use of the AJ26 rocket engines that have been used on the first five Antares vehicles unless and until those engines can be conclusively shown to be flight worthy," Thompson said.
It is not the first time that the AJ26 engines were implicated in problems. In March 2006, SpaceX failed to launch Falcon 1 because of engine failure and, in 2007, Sea Launch's expendable carrier rocket Zenit-3SL exploded due to engine clogging.
Orbital Sciences will temporarily use third-party rockets to launch Cygnus until the upgraded Antares becomes available.