WASHINGTON — Aerojet Rocketdyne will pay Orbital ATK $50 million to end a dispute about the role Aerojet’s AJ-26 engine played in last year’s Antares launch failure, the propulsion provider announced Sept. 24.

In a filing with the U.S. Securities and Exchange Commission, Aerojet said it reached an agreement to terminate its contract to supply Orbital with AJ-26 engines that had been used to power the first stage of Orbital’s Antares launch vehicle. Under that agreement, Aerojet will make a one-time payment of $50 million by the end of September, and take possession of the 10 engines remaining under that original deal. Aerojet said it plans to recoup at least part of that payment from insurers.

The agreement, Aerojet said, settles any claims the companies had against one another from the Oct. 28 failure of an Antares rocket seconds after liftoff from the Mid-Atlantic Regional Spaceport in Virginia. Orbital said in the weeks after the accident that the turbopump in one of the first stage’s two AJ-26 engines malfunctioned.

The companies had publicly disagreed on the root cause of the failure. During a panel session at the 31st Space Symposium in April, Ronald Grabe, then-president of Orbital ATK’s Flight Systems Group, said “excessive bearing wear” in the turbopump caused engine components to come into contact, leading to the failure. However, Aerojet argued at the time that the bearings might have been damaged by debris that got into the engine from elsewhere in the vehicle.

Aerojet Rocketdyne spokesman Glenn Mahone said Sept. 25 that separate investigations of the launch failure by the two companies have been completed and submitted to NASA and the Federal Aviation Administration, but that there was little the companies could publicly discuss about them. “Virtually all of the data are highly proprietary, and there is nothing meaningful we can disclose,” he said.

Aerojet’s filing did not provide additional details about the agreement, nor did it assess blame for the launch failure on either company. Mahone also declined to provide further details about the agreement. Aerojet had warned in earlier regulatory filings that the Antares accident could result in termination of its contract to supply engines, and that it “may face significant damage claims” as a result.

Orbital announced last December that it would replace the AJ-26 engine, an “Americanized” version of the Soviet-era NK-33, with the RD-181 engine from Russia’s NPO Energomash. The new version of the Antares will be ready for launch in March, Mark Pieczynski, vice president of strategy and business development for Orbital ATK’s Flight Systems Group, said Sept. 1. However, NASA’s Office of Inspector General said in a Sept. 17 report that it was more likely that launch would take place in June.

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...