NASA’s Artemis I lunar rocket prepares for a pre-launch test

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific breakthroughs and more.



CNN

The Artemis I mega moon rocket is preparing for another test on Wednesday ahead of its next launch attempt around the moon and back.

The goal is to start a mission group The Artemis I cryogenic demonstration test begins at 7:15 a.m. Wednesday, and NASA will share live coverage on its website. The Space Launch System rocket and Orion spacecraft remain on the launch pad at Kennedy Space Center in Florida.

Since the second launch attempt of the uncrewed Artemis I mission on Sept. 3, engineers have replaced two seals at the liquid hydrogen fuel line interface between the rocket and the mobile launcher, according to NASA officials. These seals were associated with a large hydrogen leak that caused the failure of the launch attempt.

When engineers replaced the seal on an 8-inch (20-centimeter) hydrogen quick-disconnect line, they found a “spot marker,” or indentation, in the seal associated with foreign object debris, Mike Sarafin, Artemis mission manager, said. NASA press conference on Monday.

The team did not recover any debris, but the draft was clear and indicated a problem that caused the hydrogen leak, Sarafin said.

The dent was less than 0.01 inch (0.3 millimeters), but it allows the release of pressurized gas, which can be very dangerous given the flammability of hydrogen. The team believes this crack is related to the leak, but test results may confirm.

On September 3, the large hydrogen leak was two to three times the approved limit, Sarafin said.

The purpose of the cryogenic demonstration is to test the seals and use updated, “kinder and gentler” loading procedures for the supercold propellant, which is what the rocket would experience on launch day.

Unlike the wet suit tests, which simulated all the pre-launch stages of Artemis I’s previous tests, the cryo test countdown focuses on a very specific aspect: the loading of supercold liquid oxygen and liquid hydrogen into the rocket’s core and upper stage.

The Orion spacecraft and rocket boosters will be without power during the test, and the team does not plan to enter the terminal countdown, or the final 10 minutes that occur during the countdown before launch, said Jeremy Parsons, deputy director of NASA’s Exploration Earth Systems Program. at the Kennedy Space Center.

The charging procedure is gentler and smoother to minimize the pressure spikes and thermals seen in previous start-up attempts. To achieve this, the team will slowly increase the pressure of the liquid hydrogen storage vessel. The slower procedures are estimated to add more than 30 minutes to the process, Parsons said.

“It’s going to be a very slow and steady ramp,” Parsons said. “So (we’re) really trying to slowly introduce some of those thermal differences and reduce thermal shock and pressure shock.”

Liquid oxygen is relatively dense, about the density of water, and is pumped into the rocket. Meanwhile, hydrogen is very light, so it moves using pressure rather than pumping, said Tom Whitmeyer, NASA’s deputy assistant administrator for joint exploration systems development.

The new charging operations will use a slower pressure rate with more gradual temperature changes, Whitmeyer said.

The call for testing stations, once all mission-related teams have arrived at their consoles and reported readiness, will begin today at 3:00 PM ET. The mission team is expected to receive the go-ahead around 7 a.m. Wednesday to begin loading the rocket with propellants. If all goes well, the team hopes to finish testing by 3 p.m. that day, Parsons said.

The test will also include engine bleeding, which cools the engines for starting. The mission team cleared Artemis I’s first attempt to launch on August 29, largely because of a faulty sensor that occurred during that bleed.

So far, the outlook looks promising for the trial. The Artemis team is receiving daily updates on Hurricane Fiona, whether the rocket stack needs to be returned to the Vehicle Assembly Building, a process that could take up to three days.

If the cryo test goes well, the next launch attempt could take place on Tuesday, September 27, with a 70-minute window opening at 11:37 AM. Mission managers will meet on September 25 to discuss test results to assess a possible launch date.

If Artemis I launches on that day, it would complete a 39-day mission and return to Earth on November 5. Another backup launch date is possible on October 2nd. Although these launch dates are recommended by NASA, it is ultimately up to a team. The decision by the US Space Force should grant a waiver for the launch.

The US Space Force, an arm of the military, still oversees all rocket launches on the East Coast of the United States, including NASA’s Florida launch site, an area known as the East Coast.

District officials are tasked with ensuring that there is no risk to people or property during a launch attempt.

The Artemis team continues to have “productive and collaborative” discussions with the Eastern Highlands, and is sharing detailed information requested by the NASA Space Force for review.

The team is taking it one step at a time and wants to pass the test before making any other decisions, Whitmeyer said.

“We’ll go when we’re ready,” said Sarafin. “But in terms of the reward of flying this flight, we’ve said from the beginning that this is the first in a series of increasingly complex missions, and it’s a stress test of the rocket.”

The inaugural mission of the Artemis program will begin a phase of NASA’s space exploration that aims to land astronaut crews in previously unexplored regions of the moon – the Artemis II and Artemis III missions, scheduled for 2024 and 2025, respectively – and eventually deliver them. Manned missions to Mars.