LE BOURGET, France — The president of the newly formed Aerojet Rocketdyne propulsion provider on June 17 said the company has secured an agreement with the manufacturers of Russia’s NK-33 engine, which powers the U.S. Antares rocket’s first stage in a version called AJ-26, to assure its long-term supply.

At a press briefing here during the Paris Air Show, Warren M. Boley Jr. said Antares prime contractor Orbital Sciences Corp. has only to sign a contract by this fall to assure that deliveries of the new engines can begin in 2016.

Originally developed for the Soviet Union’s abandoned lunar program, the liquid oxygen- and kerosene-fueled NK-33 has been out of production since the 1970s. In an undated white paper making the rounds in Washington, Orbital says that after deciding to go with the NK-33/AJ-26 for Antares, the company “learned that the available AJ-26 inventory was more limited than had previously been thought due to technical issues, additional costs to make the engines flightworthy and Russian restrictions.”

“The AJ-26 has been out of production for over 40 years and there are a finite and limited number of these engines remaining,” the Orbital white paper states. “There are enough of these engines to support Orbital’s [international space station] cargo resupply missions currently under contract and a limited number of additional missions. For Orbital to be a viable long-term competitor, it needs a long-term propulsion solution.”

The questionable availability of the AJ-26 has been of such concern to Dulles, Va.-based Orbital that the company is asking the U.S. Federal Trade Commission to void, on antitrust grounds, the agreement that gives rocket maker United Launch Alliance (ULA) exclusive U.S. access to Russia’s RD-180 engine. Orbital wants to purchase RD-180 engines, calling them “the only currently viable long-term engine solution” for Antares, which successfully debuted in April.

Boley disagreed. He said Aerojet has reached an agreement with NK-33 manufacturer Kuznetsov Design Bureau to restart motor production once Orbital gives the go-ahead. He did not disclose financial details, but gave the clear impression that the restarted production line, and the refurbishment of the 23 engines already purchased by Aerojet, would not represent an unwieldy spike in investment for Orbital and force the Antares prime contractor to seek the RD-180 as an alternative.

With Aerojet’s $550 million acquisition of Pratt & Whitney Rocketdyne now approved by U.S. antitrust regulators, the combined Aerojet Rocketdyne has an interest in both sides of the issue. The combined company is a joint-venture partner, with Energomash of Russia, in RD AMROSS, the company that supplies the RD-180 to ULA for the Atlas 5 rocket. 

Boley said he could imagine lots of reasons that ULA would have insisted on an exclusive arrangement with RD AMROSS given ULA’s investment in the RD-180. He did not issue an opinion on the arrangement.

But Boley and Aerojet have a much closer understanding of Antares and the AJ-26 engine, which has been a cause of concern at Orbital as a result of corroded parts.

Boley said it is only normal that an engine that was never meant to be stored long term shows signs of corrosion after 40 years. 

Boley said 43 NK-33 engines have been procured by Aerojet Rocketdyne. Twenty of them have been made ready for Orbital’s initial Antares missions, to deliver cargo to the international space station for NASA. Two AJ-26 engines are needed to power the Antares core stage.

The remaining 23 have not yet been worked on, but making them ready for Antares, Boley said, does not present any financial or technical obstacles that Aerojet has not already encountered with the first 20 engines.      Boley said in a June 18 briefing with reporters that in addition to these 43 engines, Kuznetsov has 12 to 18 NK-33 engines at its disposal.

“No one expected they would sit around for 40 years,” Boley said, adding that their condition is no worse than should be expected given the storage. “Through an overhaul and repair process we have addressed the corrosion.”

Orbital Sciences on June 17 issued the following statement in response to SpaceNews inquiries following Boley’s comments:

“Orbital is currently pursuing a long-term first-stage propulsion system for its new medium-class Antares launch vehicle. Orbital currently uses the Aerojet AJ26, which is derived from the Russian NK-33, and has a sufficient supply of AJ26 engines available to meet commitments to NASA for commercial cargo supply to the International Space Station. Today, the only engine in active production that is technically suitable for the Antares and available for use in the U.S. is the RD-180 engine from Russia. Orbital continues to investigate all potentially available engine options, one of which is the continued use of AJ26 engines, based on new production NK-33 engines. We will continue to work with our current supplier Aerojet, as well as explore other options, to identify the best long-term propulsion solution for Antares. At this time, we can’t be more specific because we do not comment on ongoing business discussions.”


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Peter B. de Selding was the Paris Bureau Chief for SpaceNews.