After billions of dollars and a decade of work, NASA’s plans to send astronauts back to the moon had another setback on Saturday. A planned eight-minute test shot of the four engines of a new mega-missile, which was needed for the lunar missions, ended abruptly after only about a minute.

If engineers unravel what went wrong, the rocket’s first launch will likely slide further into the future, and NASA astronauts may have to wait longer before stepping back on the moon.

However, NASA officials said it was too early to predict any delays. “I don’t currently think we have enough information to know about them,” said Jim Bridenstine, the NASA administrator, during a press conference following the test. “It depends what the anomaly was and how difficult it will be to fix.”

John Honeycutt, NASA’s program manager for the rocket, said it was too early to know if the failure was due to hardware, software, or a sensor. “It’s one of those things that the team is digging through the data,” he said.

The rocket, known as the Space Launch System, has yet to fly into space, and Saturday’s test should be a major milestone. For the first time, the four motors on the booster stage were ignited for about eight minutes to simulate what they would do during an actual start.

The vehicle is a key component for Artemis, the program designed to bring NASA astronauts back to the moon in the years to come. Although President Trump promised to make the trip by the end of 2024, few expected NASA to actually stick to that schedule.

Often abbreviated as SLS, the rocket is equivalent in the 21st century to the Saturn V that took NASA astronauts to the moon in the 1960s and 1970s. Although there are many other rockets out there today, they’re too small to launch spaceships that can carry people to the moon. (One possible exception is SpaceX’s Falcon Heavy, but a human moon mission would require two launches.)

The first version of the SLS can lift 70 tons, and future versions of the rocket can throw up to 130 tons, more than the rockets the Apollo astronauts carried.

Although the space launch system will be expensive – up to $ 2 billion per launch for a single-use missile – Congress has so far provided unwavering financial support for it. Supporters claim it is important for the government to own and operate its own powerful space rocket, and parts of the system are being built by companies across the country, spreading the economic benefits to many states and congressional districts.

The booster used in the test on Saturday was to fly around the moon and back into space in a capsule in November in an unscrewed test flight, a mission called Artemis 1. Instead of packing the booster for shipping to the Kennedy Space Center in Florida, the first thing the engineers have to do is investigate what went wrong.

The booster didn’t go anywhere on Saturday. It was held firmly to the ground on a test stand at NASA’s Stennis Space Center in Mississippi.

After a series of postponements as to when the test would take place, the engines began to fire smoothly at 5:27 p.m. Eastern time with white clouds rising from the test bench. But about 50 seconds after the ignition one of the controllers said: “MCF on Engine 4.” MCF is an abbreviation for “Major Component Failure”.

The test supervisor replied, “Copy that. But we’re still running. I still have four good engines, right? “

There was a flash of lightning around the engine which was causing problems. The missile’s automated software shut down all engines.

While the rocket is new, the engines are not. They are the same ones that were flown into orbit on NASA’s space shuttles. Two were used for the last shuttle flight in 2011. For the new rocket, the space shuttle main engines were overhauled and upgraded and given a new name: RS-25.

After the booster stage was built at NASA’s Michoud Assembly Facility in New Orleans, it was shipped to Stennis and assembled on the same test bench that tested the first stage of the Saturn V in the 1960s.

The engineers then began a series of tests that NASA called the Green Run to validate the missile systems. The test fire on Saturday should be the highlight of the green run. It was set to 8 minutes 10 seconds.

At a press conference on Tuesday, John Shannon, the manager of the Space Launch System at Boeing, who built the booster, said that the engineers gathered all the technical data they needed after about 250 seconds. However, the test on Saturday ended after only about 80 seconds.

Before moving the booster to Stennis, NASA officials had considered skipping the green run in hopes of launching the Artemis 1 mission to the moon earlier. When NASA first announced plans for the SLS in 2011, the first test attempt without screws was planned for 2017. With the recent setback, that launch will almost certainly take place in 2022 at the earliest.

If the engines were shut off during Artemis 1 launch, as it did on Saturday, the rocket might not go into orbit and the mission would be a failure.

However, since this was done on site, the engineers can diagnose and fix the problem.

“This is not a failure,” said Bridenstine, who will step down when President-elect Joseph R. Biden Jr. is inaugurated next week. “This is a test.”