The investigation into the launch failure of the Antares rocket one week ago is now focusing on the turbopump in one of the rocket’s first stage engines.
“The Investigation Board (AIB) is making good progress in determining the primary cause of last week’s failure. A preliminary review of telemetry and video data has been conducted and substantial debris from the Antares rocket and its Cygnus payload has been collected and examined,” noted Orbital on Wednesday. “While the work of the AIB continues, preliminary evidence and analysis conducted to date points to a probable turbopump-related failure in one of the two Aerojet Rocketdyne AJ26 stage one main engines. As a result, the use of these engines for the Antares vehicle likely will be discontinued.”
It was later noted that the AJ-26 could still be used if they were proven to be completely flight-worthy.
If Orbital Sciences decides to completely cease using the Russian engines, it could mean a very significant delay before they can launch again, maybe several years. If they do that, I expect them to face contract penalties from NASA for the failure to deliver cargo to ISS on a reasonable schedule. It will also mean that their chances of winning a second contract will go down significantly.
They need to replace the engine, but they also need to keep launching. The article as well as a company press release today describes how they are exploring other launch vehicles, including the Falcon 9, to launch Cygnus, but I see no reason for them to completely abandon the Russian engines immediately. What they need to do is find what failed, fix it in the remaining engines, and keep flying while they scramble hard to replace the engine entirely.