By Andy Pasztor


The National Aeronautics and Space Administration has determined that sensors flagged problems with two out of four main engines of a mammoth deep-space rocket during a key ground test that ended prematurely over the weekend.

But a spokeswoman for NASA on Tuesday said preliminary findings indicated the cause of the difficulties likely stemmed from how the test was set up for the Space Launch System booster designed by Boeing Co., rather than malfunctions or defects with the engines themselves.

Responding to questions about the cause of Saturday's premature engine shutdowns--which occurred about a minute into what was supposed to be an eight-minute test--agency spokeswoman Kathryn Hambleton said all of the engines performed as expected before the abrupt automated shutoff.

One engine stopped operating and then prompted the rest also to shut down earlier than planned, according to a separate update posted on NASA's website Tuesday, due to "test parameters that were intentionally conservative to ensure the safety" of the booster section that was being assessed.

Much earlier in the test, different sensors checking a second engine indicated a "major component failure." On Tuesday, NASA clarified that the warning stemmed from a communication issue with instrumentation intended to monitor that engine's performance, according to NASA's summary based on preliminary findings.

"Data analysis is continuing to help the team determine if a second" test firing of the engines is required, according to the summary posted on NASA's website.

Ms. Hambleton said "we do not have a firm timeline for when we will know if we will redo the test."

Retesting the engines could further delay the multi-billion dollar program that is already years behind schedule and by some measures, is about 30% over budget. NASA officials have said preparing for a retest would take at least a month. Industry officials watching the program have said they anticipate a longer delay.

NASA's latest statements, however, provide some relatively good news for backers of the SLS booster, which agency and Congressional investigators previously said experienced persistent management problems and significant technical setbacks. Ms. Hambleton indicated the engines weren't damaged during the test, while other details suggest the test didn't point to a fundamental design problem with the engines, fuel system or supporting structures.

Boeing is the prime contractor for the 212-foot tall rocket, which is more powerful than the Saturn V that blasted Apollo astronauts toward the moon in the late 1960s and early 1970s. It was slated for its first uncrewed launch late this year, but that schedule is now in flux.

Political and budget pressures on the program, projected to cost a total of between $19 billion and $23 billion to complete, were already increasing. Under development for more than a decade without getting airborne so far, each launch is projected to cost in excess of $1 billion, according to agency officials and NASA's inspector general's office.

SLS boosters are intended to carry astronauts inside the Orion capsule, built by a team headed by Lockheed Martin Corp., to the moon and eventually to Mars. But with new appointees set to take over NASA under a Biden administration, SLS is widely expected to face stepped-up Congressional scrutiny and escalating competition from rival space-transportation companies.

Commercially-developed smaller rockets separately championed by companies headed by Elon Musk and Jeff Bezos, the founder of Inc., potentially could be tapped by NASA to participate in early lunar missions.


Write to Andy Pasztor at


(END) Dow Jones Newswires

January 19, 2021 15:05 ET (20:05 GMT)

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