The SLS was supposed to light its engines for about eight minutes, the length of time the engines will have to fire to propel the rocket on its orbital missions.
During a Saturday night news conference, John Honeycutt, the SLS program manager, said NASA officials will go over the data gathered in the test to identify the issue.
“What we learned was — is that we didn’t have the pressurization valve modeled appropriately,” Honeycutt said.
Officials had hoped to run the test for at least 250 seconds, he said.
During the hot fire test, engineers “power up all the core stage systems, load more than 700,000 gallons of cryogenic, or supercold, propellant into the tanks and fire all four engines at the same time,” according to NASA.
It is unclear if another test will be needed before the rocket is shipped to Florida, the launch site where the rocket is expected to make its first journey into outer space.
Rick Gilbrech, director of the Stennis Space Center, said his site would need at least four to five days to prepare the fuel for another test if the rocket is ready. He and his team aren’t discouraged by Saturday’s test and are proud of what they’ve accomplished this year, especially during the Covid-19 pandemic, he said.
NASA administrator Jim Bridenstine said the test was “not a failure.”
“This is not a failure. This is a test, and we tested today in a way that is meaningful where we’re going to learn … we’re going to make adjustments, and we’re going to fly to the moon,” he said.
“This was a successful day. We didn’t get everything we wanted and yes we’re going to learn, we’re going to have to make adjustments,” he said. “But again, this is a test. And this is why we test.”
Yet another delay
“We got lots of data that we’re going to go through and be able to sort through and get to a point where we can make determinations as to whether or not, you know, launching in 2021 is a possibility or not,” Bridenstine said.
At one point, Bridenstine reportedly considered skipping the green run test to expedite SLS’s development. But more recently he has asserted that the tests are essential to ensuring the rocket is safe enough to carry humans into space and to work out any potential engineering problems before attempting an orbital launching.
NASA’s Artemis I mission is expected to launch by the end of 2021 with two test flights around the moon without astronauts.
A crewed test mission, Artemis II, is set to launch in 2023 in preparation to have the Artemis III mission return astronauts to the surface of the moon in 2024 for the first time since the 1970s.
CNN’s Katie Hunt and Hollie Silverman contributed to this report.