NASA studying cause of early end to NASA moon rocket test-firing - Spaceflight Now

A critical test-firing of NASA’s Space Launch System moon rocket in Mississippi ended just 67 seconds after it began Saturday, well short of a planned eight-minute burn that was supposed to clear the way for the space agency to finally ship the rocket’s core stage to the Kennedy Space Center in Florida for launch preparations.

The SLS core stage, built by Boeing, lit its four Aerojet Rocketdyne RS-25 engines for the first time at 5:27 p.m.

Fastened to the mammoth B-2 test stand at Stennis, the 212-foot-tall (98-meter) SLS core stage throttled up to full power after the four main engines lit at 120-millisecond intervals.

The engines, leftovers from the space shuttle program, built up to 1.6 million pounds of thrust, making Saturday’s hot fire test the most powerful rocket firing at the Stennis Space Center since NASA tested the Apollo-era Saturn 5 moon rocket on the same stand in the 1960s.

Before the test-firing Saturday, NASA officials said preparations were on track for the first test flight of the Space Launch System at the end of 2021.

The Space Launch System is a major piece of NASA’s Artemis program, which aims to return astronauts to the moon for the first time since 1972.

Here’s a replay of the first hotfire test of the Space Launch System core stage, which was cut short a little more than a minute into a planned eight-minute firing.

During development of the Saturn 5 moon rocket and the space shuttle, NASA fired test articles at Stennis to verify the propulsion system design.

“At that point in time … the engine controller sent the data to the core stage controller to shut the vehicle down,” Honeycutt said.

John Shannon, Boeing’s SLS program manager, said before the test-firing teams wanted to get at least 250 seconds of run time on the core stage before moving on from the hot fire.

Bridenstine said Saturday it was too soon to know for sure whether engineers will need to perform another core stage hot fire test, or whether the early engine shutdown is likely to delay the first SLS test launch, known as Artemis 1 the mission, into 2022.

NASA could have shipped the SLS core stage to the Kennedy Space Center before the end of February if Saturday’s test-firing went perfectly, and moved the stage into place for stacking with two solid rocket boosters, an upper stage, and the Orion spacecraft.

It takes three to four weeks to dry out the RS-25 engines, perform inspections, and ready the core stage for a second hot fire test, assuming managers decide to go for another test-firing, Honeycutt said.

NASA has spare RS-25s available if engineers need to replace one of the engines on the first SLS core stage

Ground crews at Stennis could swap engines with the rocket mounted on the test stand, officials said

“We’ve got to fully understand the problem, and do an assessment of the core stage as well as the engines to make sure we understand the problem and what needs to be fixed or repaired, if we need to,” Honeycutt said Saturday night

Asked if any of the data analyzed so far suggest engineers need to make any major changes to the core stage, Honeycutt said: “What I’ve seen so far about the performance of the hardware during the wet dress rehearsals that we’ve had, during the hot fire today, and the limited amount of imagery I’ve been able to see so far, I don’t think we’re looking at a significant design change.”

Live coverage: SLS core stage engines shut down early during critical hotfire test