Hydrogen leak forces Artemis moon landing rocket delayed for weeks

On Saturday, NASA’s Interstellar Space Launch System lunar rocket was grounded for the second time in five days, this time due to a massive hydrogen leak in the fuel line’s quick disconnects that will cost the $4.1 billion boost. The first flight of the aircraft was delayed by several weeks, most likely in October.

The latest delays, much to the dismay of the Kennedy Space Center staff, invited guests and thousands of area residents and tourists to watch NASA’s most powerful rocket launch from area roads and beaches, kicking off the agency’s Artemis Curtain of the Lunar Program.

But faced with a massive hydrogen leak and not enough time for repairs before the current lunar launch period ends on Tuesday, NASA administrators had no choice but to order a delay Artemis 1 Test flight.

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As engineers work by remote control, oxygen vapor flows out of the Space Launch System rocket to try to stop a leak of hydrogen in the quick-disconnect device on the bottom of the rocket, where ultracold propellant is fed into the first stage of the booster. After three unsuccessful attempts, the launch was canceled.

NASA


Engineers are evaluating two options for solving the latest problem: replacing components in questionable fittings on the launch pad and conducting a small refueling test using liquid hydrogen to verify leak-free performance. Or roll the rocket back to the vehicle assembly building and have it repaired there.

While the VAB can provide shelter from the weather and does not require the assembly of an environmental enclosure to protect sensitive components during repair work, engineers will not have access to low-temperature hydrogen test accessories. That’s when a leak is most likely.

Either option means a multi-week release delay. The next lunar launch period begins on September 19 and runs until October 4. But NASA plans to launch new astronauts to the International Space Station in a SpaceX capsule on Oct. 3, and the agency wants to avoid conflict.

That means the SLS launch is likely to move into the next launch period, which begins on October 17 and continues until Halloween, unless a solution is found to expedite repair work.

“It’s a very difficult task,” said Mike Sarafin, mission manager for Artemis One. “Our focus is to understand the issues. … We’ll follow up next week when these options are rolled out further.”

During Saturday’s countdown, engineers made three unsuccessful attempts to properly “seize” the suspect seal in the 8-inch quick-disconnect. Launch Director Charlie Blackwell-Thompson canceled the countdown at 11:17 a.m. ET after the engineer who solved the problem suggested a “no ban.”

“We’re going when we’re ready,” said NASA Administrator Bill Nelson. “We’re not going until then, especially now, for test flights.”

It’s unclear what caused the leak, but Sarafin said that during the initial moments of the fuel-loading operation, a valve inadvertently cycled, briefly pressurizing the piping and quick-disconnect fittings.

“The pressure in the hydrogen delivery line unexpectedly exceeded our plan by about 20 pounds per square inch,” he said. “It got to about 60 pounds per square inch. The flight hardware itself, we knew it was fine, we didn’t exceed the max. design pressure.

“But it’s possible that the soft cargo or the seals in the 8-inch quick disconnect had some impact from that, but it’s too early to tell…all we know is we’ve seen a lot of leaks. “

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The Space Launch System lunar rocket refueled on launch pad 39B for its first test flight on Monday. The rocket was grounded due to a hydrogen leak in the system that delivers propellant to the first-stage storage tank.

NASA


The goal of the Artemis 1 mission is to propel the unmanned Orion capsule into distant lunar orbit, test the spacecraft in a deep space environment, and then return it to Earth for a high-velocity, high-temperature reentry.

If the initial uncrewed test flight goes well, NASA plans to launch four astronauts on a test flight around the moon, Artemis 2, in 2024, and send the first woman and the first woman to the moon in the 2025-26 time frame. Two men landed near the south pole of the moon. But it all hinged on a successful Artemis 1 test flight.

The long-awaited mission must take off during a specific launch cycle based on the changing positions of the Earth and Moon, the lunar orbit required by the Orion spacecraft, and the power of the SLS rocket to put it in the correct orbit.

Complicating the plans, flight planners wanted to avoid placing solar-powered spacecraft in the lunar shadow for extended periods of time, and wanted to ensure sunlight sputtering.

The current launch window closes on Tuesday, the same day the certification of batteries in the rocket’s self-destruction system expires. That alone would require a rollback to the vehicle assembly building for already planned repairs, as the battery was not accessible at the launch pad.

NASA tries to launch SLS rocket on Monday’s maiden flight After four countdown rehearsals and refueling tests, all of which encountered multiple technical hurdles, including hydrogen leaks in different systems.

During Monday’s launch attempt, a faulty temperature sensor led to uncertainty about whether the SLS rocket’s four RS-25 first-stage engines were receiving proper pre-launch cooling.

In addition, the same fitting that leaked on Saturday also leaked during Monday’s launch attempt, but at a much lower concentration, and engineers managed to file the hydrogen tank before the engine cooling problem arose.

It turns out, in fact, that the engine was properly cooled, and a faulty temperature sensor was what misled the engineers.

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