Ronald Grabe
Ronald Grabe, president of Orbital ATK's flight systems group, during a launch industry panel discussion at the 31st Space Symposium. Credit: SpaceNews/Tom Kimmell

COLORADO SPRINGS, Colo. — A report on the October failure of an Antares launch vehicle is due to be delivered to the Federal Aviation Administration within days, with a problem in an engine turbopump identified as the most likely cause of the failure, an Orbital ATK executive said April 14.

In a panel session during the 31st Space Symposium here, Ronald Grabe, president of the company’s flight systems group, said that an Orbital-led investigation into the Oct. 28 launch failure would submit a report to the Federal Aviation Administration “within days.”

Grabe said the investigation concluded there was “excessive bearing wear” in the turbopump of one of the two AJ-26 engines in the Antares stage. That bearing wear causes rotating and stationary parts of the turbopump to come into contact, which in turn caused the failure of the turbopump and the engine itself.

Orbital — under the oversight of the FAA — is leading the investigation into the failure, which destroyed a Cygnus cargo spacecraft bound for the International Space Station. NASA is carrying out its own independent review of the accident, Grabe said, and Aerojet Rocketdyne, which provided the AJ-26 engines, is carrying out a separate investigation.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...