Blue Origin BE-4 Engine Exploded During Test June 30

It came to light today, by a report on CNBC, that a BE-4 engine under final Acceptance Testing before delivery to United Launch Alliance exploded during the engine's test.   

During a firing on June 30 at a West Texas facility of Jeff Bezos’ space company, a BE-4 engine detonated about 10 seconds into the test, according to several people familiar with the matter. Those people described having seen video of a dramatic explosion that destroyed the engine and heavily damaged the test stand infrastructure.

The people spoke to CNBC on the condition of anonymity to discuss nonpublic matters.

The engine that failed was scheduled to complete test this month and then be shipped to ULA for use on the second Vulcan Centaur being assembled for launch, currently estimated to be in second quarter of '24. 

“No personnel were injured and we are currently assessing root cause,” Blue Origin said, adding “we already have proximate cause and are working on remedial actions.”

The company noted it “immediately” made its customer ULA aware of the incident.

ULA's President and CEO, Tory Bruno issued a statement via Twitter implying that he wasn't particularly concerned about the failure, saying that there's a progression of tests that are done during development with the final qualification test being the final word on the design.  The BE-4 is already qualified so this is regarded as a failure of an assembly during production test which could happen to any manufactured item.  This is why production acceptance testing is done.  That's not unreasonable.

Blue's statement with the term proximate cause seems to be saying they know the cause of this explosion and adds they have not completed a root cause analysis.  That's important.  The difference could be saying, for example, that the proximate cause is that some particular valve malfunctioned, and the root cause might be that a previous test step wasn't adequate to find the failed valve or that in some engines, the operating conditions extend beyond the specifications for the valve.  In the first case, the solution might be to redesign the previous tests; in the second, the solution could be to re-specify the valve.  Either one could impact the cost of the engines or the amount of time required to build and test a BE-4. 

The BE-4 engines, of course, are to be used on Blue Origin's own New Glenn heavy lift rocket and neither ULA's Vulcan Centaur or the New Glenn have flown yet.  Bruno is scheduled to talk to reporters about Vulcan Centaur on Thursday (July 13).  Blue Origin has recently declined to provide a new target launch date for New Glenn.