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As Orbital Sciences Corporation looks for clues to Tuesday’s catastrophic failure of its Antares launcher, three independent industry insiders tell Forbes that the blame squarely rests on one of two of the rocket’s Soviet-era engines.
Speaking on condition of anonymity, a launcher engineer and industry expert told Forbes that before the Antares vehicle lost thrust it was evident that “there was a lot of unburned kerosene going into the exhaust stream” which he says suggests that it also lost engine pressurization.
“It wasn’t a failure in the fuel tanks, avionics, or navigation, but definitely with an engine,” said the launcher engineer. “Seven seconds into the flight everything is fine and then suddenly the exhaust stream brightens noticeably.”
The Orbital Sciences Corporation Antares rocket seen on launch Pad-0A during sunrise, Sunday, Oct.... [+]
The Antares two-stage launcher system, which NASA tasked with re-supplying the International Space Station (ISS), experienced a catastrophic failure which triggered a self-destruct scenario within seconds after liftoff at 6:22 PM EDT from NASA’s Wallops Flight Facility on Virginia’s Atlantic shore.
The rocket’s two engines were modified Soviet-era hardware initially acquired from Russia in the late 1990s by the now defunct Kirkland, Wa.-based Kistler Aerospace Corporation. At the time, prior to its merger with Rocketdyne, the Sacramento, Ca.-based Aerojet Corporation had been subcontracted by Kistler to modernize the engines. However, Aerojet subsequently gained title to the engines as part of Kistler’s bankruptcy settlement.
“They were originally developed by the Soviet Union for their N-1 manned lunar rocket which experienced several failures resulting in the Soviet cancellation of their manned lunar landing program,” said Bill Ketchum, a retired
The Aerojet Rocketdyne modifications mainly were to allow the engines to gimbal (making them steerable); to inspect them for cracking and to integrate them with new control electronics, plumbing and wiring.
Aerojet Rocketdyne gave the engines the new “AJ-26” designation number and eventually sold them to the Dulles, Va.-based Orbital Sciences; that is, shortly after Orbital Sciences entered into a commercial contract with NASA for unmanned cargo resupply missions to the ISS.
“Those NK-33/AJ-26 engines had been stored in 1975 in a non climate-controlled warehouse,” said Dennis Wingo, an engineering physicist and CEO of Skycorp Incorporated at Moffet Field, Ca. “No one wanted them, until Orbital Sciences came along with their Antares vehicle.”
Wingo says the most likely culprit in Tuesday’s launch failure is hardware stress, corrosion and cracking leading to engine failure, but he notes it could have also been a fuel line crack or rupture.
These modified engines have a history of trouble, with Orbital Sciences having had two more of these engines fail on the test stand.
How does Tuesday’s Antares failure affect long-term cargo resupply for the space station?
“It takes the U.S. companies doing [ISS cargo resupply] from two down to one for at least a while,” said the launcher engineer. “I’d be surprised if Orbital Sciences flies Antares again in a year. This definitely calls into question their long-term strategy of using these old Soviet engines.”
In lieu of using their remaining AJ-26 engines, Orbital Sciences has only a few options --- build a new engine from scratch themselves; pay for a new engine design from a subcontractor; or opt for solid fuel rockets, says the launcher engineer. NASA tried solid fuel engines with its Constellation program’s Aries I and the space agency ran into a lot of difficulty, he says. Although the launcher engineer notes that there may be pressure for Orbital Sciences to also try for solid fuel rockets, he sees that as another recipe for failure.
“So, I wouldn’t be surprised if next month, Orbital Sciences came out and said that they were going back to the Russians for a new engine design,” said the launcher engineer. “That’s not a very sound strategy because a domestic supplier that uses Russian technology still leaves NASA at the mercy of the Russians.”
It’s also a cheap but unwise fix, says the launcher engineer.
When contacted for comment, Orbital Sciences spokesperson Sean Wilson refused to be drawn into a discussion of the malfunctioning launcher’s problems.
“Until the investigation is complete, we can't speculate on what caused the failure,” Wilson told Forbes.
