- Parabolic Arc
- November 29, 2023
Orbital, Aerojet Rocketdyne Disagree on Cause of Antares Explosion
After the explosion of an Antares rocket in October, NASA left the investigation in the hands of the company’s that bands of the company that built and launched the rocket, Orbital Sciences Corporation (now Orbital ATK). Yesterday, we got the first official word on what that investigation has found. And it’s very confusing.
Orbital ATK Executive Vice President Ronald Grabe said during the 31st Space Symposium that the failure was caused by excessive wear in the bearings of a turbo pump for one of the two first-stage AJ-26 engines supplied by Aerojet Rocketdyne.
Grabe said the company’s report would be turned over to the Federal Aviation Administration within days.
So, mystery solved. Responsible party identified. Orbital not at fault.
Not so fast, says Aerojet Rocketdyne’s parent company.
GenCorp spokesman Glenn Mahone said the company’s independent investigation would be completed in about three weeks, but the bulk of the work had been done. He said Orbital’s statement was “inaccurate and could be misleading.” He said GenCorp’s investigation had also identified excessive wear of the bearings as the direct cause of the explosion that destroyed the rocket, but further research revealed that the bearings likely wore out due to “foreign object debris” in the engine.
The debris (known as FOD) would probably have been sucked in from one of the fuel tanks, which are built by a Ukrainian company. It was Orbital’s responsibility to make sure no debris was present in the tanks before mating.
Meanwhile, NASA is conducting its own assessment of the launch failure, which destroyed an agency-funded Cygnus spacecraft that was headed for the International Space Station. NASA has no plans to release that report publicly.
Orbital has decided not to continue using AJ-26 engines, which 40-year old refurbished NK-33 motors left over from the Soviet Union’s manned lunar program. Instead, they are switching over to new Russian-built RD-181 engines.
Even with the engine change, the inability of the parties to identify a root cause is disturbing because it’s happened before. In 2009, Orbital launched NASA’s $278 million Orbiting Carbon Observatory into the ocean after the payload shroud of its Taurus XL booster failed to separate.
Two years later, Orbital did it again, destroying NASA’s $424 million Glory satellite when the payload shroud again failed to separate on the Taurus XL launch vehicle. In between the flights, Orbital said it had identified and fixed problem, but engineers did not appear to have identified the root cause.
One really has to question the decision to allow Orbital to investigate itself on the Antares failure. And why is NASA keeping its own inquiry secret?
I don’t know if that is stipulated in NASA’s commercial cargo agreement Orbital, but it raises questions about whether the public will get a clear answer as to what caused the failure. NASA funded the mission and paid Orbital the majority of the contracted amount despite the fact Cygnus go nowhere near the space station.