NASA’s Artemis moon mission rocket prepares for pre-launch test

The Artemis 1 mega lunar rocket is gearing up for another test Wednesday before its next launch attempt to travel around the Moon and back.

The mission team intends to begin the Artemis 1 cryogenic demonstration test at 8:15 am ET on Wednesday, and NASA will share the 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 unmanned launch attempt of the Artemis 1 mission on September 3, engineers have replaced two seals at an interface for the liquid hydrogen fuel line between the rocket and the mobile launcher, according to NASA officials.

These seals were associated with a large hydrogen leak that led to the failure of the launch attempt.

When engineers replaced the seal on a 20-centimeter quick-disconnect line for hydrogen, they found a “witness marker” or notch in the seal associated with foreign object debris, Mike Sarafin, manager of the Artemis mission, told a news conference. NASA press.

The team did not recover any pieces of debris, but the dent was clear and pointed to a problem that contributed to the hydrogen leak, Sarafin said.

The recoil was below 0.3 millimeter, but it allows pressurized gas to leak out, something that can be very dangerous due to the flammability of hydrogen. The team believes the dent is associated with the leak, but test results can confirm this.

On Sept. 3, the large hydrogen leak was between two and three times the accepted limit, Sarafin said.

Testing ‘kinder’ procedures

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

Unlike wet suit trials, the earlier Artemis I trials that simulated all the steps leading up to launch, cryogenic testing focuses on a very specific aspect of the countdown: loading supercold liquid oxygen and liquid hydrogen into the center stage and into the upper stage of the rocket.

The Orion spacecraft and rocket boosters will remain without power during the test, and the team does not intend to go into the terminal count or the final 10 minutes that occur in the pre-launch countdown, said Jeremy Parsons, deputy systems program manager. NASA Land Exploration at the Kennedy Space Center.

The gentlest and smoothest loading procedure is to minimize pressure spikes and thermal spikes observed during previous launch attempts. To accomplish this, the team will slowly increase the pressure in the liquid hydrogen storage tank. The slower procedure is estimated to add no 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 just trying to slowly introduce some of these thermal differences and reduce the thermal and pressure shock.”

Liquid oxygen is relatively dense, roughly the density of water, and is pumped into the rocket. Meanwhile, hydrogen is very light, so it’s moved using pressure rather than being pumped, said Tom Whitmeyer, NASA’s deputy associate administrator for common exploration systems development.

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

The call to stations for testing, when all teams associated with the mission arrive at their consoles and report they are ready, starts today at 4pm. The mission team expects to receive a “go” to begin loading the rocket with propellant around 8 am on Wednesday. If all goes well, the team expects the test to be completed by 4 pm that day, Parsons said.

The test will also include an engine bleed, which cools the engines for launch. The mission team scrapped the first launch attempt for Artemis I on August 29, largely due to an issue with a faulty sensor that occurred during this bleed.

So far, the forecast looks promising for the test. The Artemis team is receiving daily briefings on Hurricane Fiona in case it has any impact on whether or not the rocket stack needs to be rolled back to the Vehicle Assembly Building, a process that can take three days.

Preparing for launch

If the cryogenic test goes well, the next launch attempt could take place on Tuesday, September 27, with a 70-minute window that opens at 12:37 pm ET. Mission managers will meet to discuss test results on September 25 to assess a possible launch date.

If Artemis I launches on that day, it will do a 39-day mission and return to Earth on November 5th. Another backup release date is possible on October 2nd.

While these launch dates are recommended by NASA, the team is dependent on a decision by the US Space Force, which would need to issue a launch waiver.

The US Space Force, an arm of the military, still oversees all rocket launches from the East Coast of the United States, including the NASA launch site in Florida, and this area is known as the Eastern Range.

Range officers are tasked with ensuring that there is no risk to persons or property with any launch attempt.

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

The team is taking it one step at a time and wants to pass the test before further decisions are made, Whitmeyer said.

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

The inaugural mission of the Artemis program will kick off a phase of NASA’s space exploration that aims to land diverse crews of astronauts in previously unexplored regions of the Moon — on the Artemis 2 and Artemis 3 missions, scheduled for 2024 and 2025, respectively — and eventually, deliver manned missions to Mars.