NASA’s flawed lunar rocket test could delay 2021 launch

NASA’s lunar mega-rocket encountered a problem during a critical test on Saturday, and the error could further delay the agency’s efforts to send astronauts back to the moon.

The rocket, called the Space Launch System (SLS), is designed to ultimately hold 365 feet (111 meters) and carry astronauts to the Moon between the mid to late 2020s. The system is a critical part of a larger program. vast effort called Artemis, an effort of around $ 30 billion to put the boots back on the lunar surface for the first time since 1972. NASA spent around $ 18 billion to develop the rocket.

The main stage of the SLS – the largest part of the system and its structural backbone – was assembled and securely attached to the Stennis Space Center in Bay St. Louis, Mississippi, on Saturday for a critical “hot fire” test. For the first time, the rocket was ready to fire its four powerful RS-25 engines simultaneously as it would for launch.

NASA

The main stage is the largest and most powerful rocket stage in the world, according to NASA. It houses five main sections, including a 537,000 gallon (2 million liters) tank for liquid hydrogen, a 196,000 gallon (742,000 liters) tank for liquid oxygen, four RS-25 engines, avionics computers and ‘other subsystems. Boeing is the prime contractor for the scene, and Aerojet Rocketdyne is responsible for its RS-25 engines, which were used to power NASA’s fleet of space shuttles.

On Saturday, the fuel tanks were filled with 733,000 gallons of cryogenic propellant and the engines were brought to life around 5:27 p.m. EST.

“It was like an earthquake,” NASA administrator Jim Bridenstine told reporters at a press conference after the test. “It was a wonderful moment. And it just brought joy that after all this time we now have a rocket. The only rocket on the face of the planet capable of taking humans to the moon fired the four RS-25 engines. at a time.”

The engines were supposed to fire continuously for eight minutes. But just a minute after the test, they suddenly stopped.

The whole thing was captured during the NASA live broadcast:

Following the publication of this story, which indicated that there was an issue with one of the engines, Ryan McKibben, deputy chief of mechanical operations at NASA’s Stennis Space Center, reached out to Insider with new details on the ‘anomaly.

“I can assure you, as the test driver, that we did not complete the test prematurely because of our engines,” McKibben said. “We brought out a redundant sensor on an engine. But the engine was and still is in great condition after the test. The cut was due to other reasons.”

This particular rocket stage is the one that is ready to fly Artemis 1 – an unmanned test flight around the moon. NASA doesn’t want to push the rocket too hard enough to damage it during testing, so they set cautious limits on equipment operations for Saturday’s scorching fire.

In a blog post on Tuesday, NASA said its preliminary investigation into the hot fire revealed that these strict limits may have been the cause of the shutdown.

‘No, it’s not a failure’

During the scorching fire, the engines “gimbaling”, or rotated, to mimic the way they would move to direct the rocket’s thrust during flight. The systems that control these movements are powered by Auxiliary Power Units (CAPUs) in the central floor.

NASA television

When the CAPU hydraulic system for Engine 2 has exceeded conservative NASA limits, the flight computers automatically stop the entire test.

“If this scenario had occurred during flight, the rocket would have continued to fly using the remaining CAPUs to power the engines’ thrust vector control systems,” NASA said in its post.

Two other problems arose during the hot fire, although they were not significant enough to stop the operation. Engine 4 lost a redundant sensor, which led it to register a “major component failure” approximately 1.5 seconds after the start of firing. Controllers also saw a flash next to the thermal protection blanket covering this motor, although the blog post did not reveal any findings on what could have caused it.

At the time of the shutdown, “we still had four good engines running at 109%,” John Honeycutt, SLS program manager at NASA’s Marshall Space Flight Center, told a press conference.

“The amount of progress we’ve made here today is remarkable. And no, it’s not a failure. It’s a test. And we’ve tested today in a way that’s significant, where we are going to learn and we “We’re going to make adjustments and we’re going to fly to the moon,” Bridenstine said.

NASA may need to redo the hot fire test

Saturday’s burning fire was supposed to be the eighth and final stop in NASA’s “Green Run,” a program designed to thoroughly test every part of the Main Phase before SLS’s first launch for Artemis 1, currently scheduled for November 2021 .

NASA via Associated Press

But that timeline may be unrealistic now. If the searing fire went well, NASA planned to ship the rocket to the Kennedy Space Center in Cape Canaveral, Fla., In February. There, the workers would stack all the segments of the two boosters needed to send Artemis 1 around the moon.

It’s unclear how long it will take NASA to correct the engine error and bring the main stage to Florida now.

“It depends on the nature of the anomaly and how difficult it is to remedy it. And we have a lot to learn to understand that,” Bridenstine said. “It could very well be something that is easily fixable and that we could feel confident going down to Cape Town and sticking to the schedule. It is also true that we might find a challenge that will take longer.”

NASA / Robert Markowitz

The agency may need to redo the hot fire test. The SLS team wanted to achieve at least 250 seconds of engine start to have great confidence in the vehicle. Saturday’s test only lasted 67 seconds.

“My advice would be to repeat the test and get the full data,” said Wayne Hale, retired NASA space shuttle flight director. Twitter after NASA updates of its preliminary investigation. “Maybe a few weeks, but the timing is secondary.”

It would take at least four or five days to prepare the Stennis Space Center facilities for another test. If NASA needs to swap current engines for new ones, workers can do so on-site at the Stennis Space Center. Honeycutt estimated that it would take between seven and ten days to achieve this.

“This is why we are testing,” Bridenstine said. “Before we put American astronauts on American rockets, this is when we need them to be perfect.”

This story has been updated with new information. It was originally released at 8:17 p.m. EST on January 16, 2021.

Dave Mosher contributed reporting.