Soviet-era engines draw scrutiny after rocket explosion
The spectacular explosion over the Eastern Shore of Virginia's northeastern flank Tuesday night may trace its roots to an unsuccessful Soviet Union rocket program.
The investigation into what caused the unmanned Antares rocket to explode seconds after liftoff at NASA Wallops Flight Facility was only just beginning Wednesday. But analysts and the head of the company that built the rocket were focusing their attention on the craft's powerful engines and their circuitous history.
"This investigation may or may not lead us to the conclusion that the failure was caused by a problem with the Antares first-stage main propulsion system," Orbital Sciences' CEO David Thompson told investors on a conference call.
The AJ26 engines, he acknowledged, have "presented us with some serious technical and supply challenge in the past." Thompson announced that Orbital Sciences would accelerate efforts in place more than a year before Tuesday's accident to develop an alternative propulsion system.
But he hastened to add that pinpointing "the most likely of causes" was still days away and that "it may take a little longer than that to zero in on the exact root cause."
Orbital is leading the investigation with the assistance of NASA and other agencies, officials said. A NASA official deferred questions about the investigation to Orbital.
The launch was intended to deliver 5,000 pounds of science and research materials, crew supplies, 1,300 pounds of food, and 1,400 pounds of vehicle hardware to the International Space Station. The Cygnus spacecraft was to have spent more than a month attached to the space station after docking with it Sunday.
But Orbital Sciences' third resupply mission under its contract with NASA ended with a ball of flames and plume of smoke instead.
Tuesday's explosion brought long-simmering concerns about Orbital Sciences' engine choice to a boil.
The engines were built by Soviet scientists about 40 years ago for a then-secret moon rocket program, said Jonathan MacDowell, an astrophysicist at Harvard-Smithsonian Center for Astrophysics. Each of the four attempts to put the rocket into space failed, and the program was scrapped.
The unused engines sat in plastic bags for decades until a propulsion company, Aerojet, brought them to the United States in the 1990s, according to the publication Spaceflight Now. The company updated the engines' flight and control systems in the hope of obtaining a contract with Lockheed Martin.
Lockheed ended up selecting a different engine, leaving the Soviet relics to languish once again. Orbital Sciences dusted them off in 2007 with the Antares program and had them further modified.
"That scared me when I first heard about it," MacDowell said of the engines' revival. "Materials degrade. A little bit of oil can chemically react with something, so there are reasons to be a little bit nervous with something that's been sitting around for a long time."
Watching video of Tuesday's explosion, MacDowell said, a bright flash can be seen near the rear of the rocket. That suggests a fire or explosion in the first-stage engines, he said.
The question is whether the engines blew up on their own or something else set them off, MacDowell said.
John Logsdon, a space policy expert at George Washington University, also suspected the engines at first blush. But he cautioned against jumping to conclusions because of their age.
"I'm old. That doesn't make me not good," Logsdon said. The engines have "been used successfully in three or four Antares launches previously."
It turns out there isn't much of a market for rocket engines. The U.S. has contracts with just two companies for the space station resupply missions: Orbital Sciences and SpaceX.
Orbital Sciences had little choice but to use the Soviet engines, Logsdon said.
"When Orbital looked at alternatives, this was the best that they had," he said, adding that SpaceX makes its own rocket parts.
Another Orbital official echoed that sentiment after Tuesday's crash.
"When you look at it there are not many other options around the world in terms of using power plants of this size, certainly not in this country, unfortunately," said Frank Culbertson, Orbital's executive vice president.
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