By Andy Pasztor 

NASA is wrestling with the decision whether to redo ground checks of a mammoth deep-space rocket's main engines, which prematurely shut off during an aborted test Saturday.

NASA officials on Tuesday said preliminary findings indicated that sensors flagged problems with two out of four main engines of the Space Launch System booster built by Boeing Co. But in a briefing for reporters, they clarified earlier updates by revealing that the testing setback resulted from the combination of a malfunctioning sensor and how Saturday's test was set up rather than design or production defects with the engines themselves.

Outgoing National Aeronautics and Space Administration chief Jim Bridenstine and some top aides emphasized that on top of probable schedule delays, extra testing could stress parts of the 212-foot rocket to the point that performing its mission could be problematic.

The agency didn't give a timeline for a decision, though some of its internal safety guidelines suggest that typically a new test would be necessary to demonstrate reliability of the booster's primary propulsion system.

The looming trade-offs over testing present engineering and political challenges for NASA as well as Boeing, even as new appointees in a Biden administration are expected to reassess the status of the troubled multibillion-dollar SLS program.

Responding to questions about the automated shutdowns that occurred about a minute into what was supposed to be an eight-minute test on Saturday, Mr. Bridenstine and other agency leaders placed the blame on test parameters that were intentionally conservative to protect the booster section. When a sensor recorded excessive stress on the hydraulic system that adjusts the engines, a cascade of protective computer messages followed, almost instantly shutting them all down.

John Shannon, Boeing's SLS program manager, told reporters "there is a judgment call" in seeking to extract maximum data under such test situations while also "making sure that the hardware stays in good shape" for its ultimate flight.

There was an unrelated problem much earlier in the test. A different sensor monitoring another engine indicated a major component failure. NASA said Tuesday that based on preliminary data, there was no such failure and the sensor provided incorrect information to onboard computers. During an actual blastoff count, according to the agency, the malfunctioning sensor likely would have caused an abort of the launch.

Retesting the engines could further delay a program that is already years behind schedule and, by some measures, about 30% over budget. Last weekend's test in Mississippi was earlier delayed for technical reasons and then by the pandemic. Now, NASA officials must decide whether to ship the booster to the launch site in Florida without getting all the test data they initially indicated would be necessary to determine the reliability of its propulsion system. 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 have said experienced persistent management problems and significant technical setbacks. NASA said the engines weren't damaged during the test, while other details indicate the shutdown didn't point to a fundamental design problem with the engines, fuel system or supporting structures.

SLS is more powerful than the Saturn V that blasted Apollo astronauts toward the moon in the late 1960s and early 1970s and was slated for its first uncrewed launch late this year, but that schedule is now in flux.

"The fact that we learned and are learning" from the data collected on Saturday "means this was a great test," according to Kathy Lueders, head of NASA's human exploration programs. "We have a shot at flying this year," she said, though none of the NASA or industry experts at the press conference vouched for that schedule.

Political and budget pressures on the program -- projected to cost a total of between $19 billion and $23 billion -- were already increasing. The system has been under development for more than a decade without yet getting airborne. 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 the program is expected to face stepped-up congressional scrutiny and escalating competition from rival space-transportation companies.

Companies headed by billionaires Elon Musk and Jeff Bezos are separately working on smaller rockets that potentially could be tapped by NASA to participate in early lunar missions.

Write to Andy Pasztor at andy.pasztor@wsj.com

 

(END) Dow Jones Newswires

January 19, 2021 22:27 ET (03:27 GMT)

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