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NASA teams examining pad hardware at Kennedy Space Center found a possible culprit behind a leaking hydrogen line, which this week scoured the final attempt of the Artemis I moon mission, making way for a fuel test.
Managers and engineers have begun preparing for his arrival at the Launch Control Center starting Monday evening, a process that will essentially run through a simulated countdown similar to launch day. On Wednesday, Sept. 21 at 3:40 a.m., teams will clear Pad 39B of the Space Launch System rocket and slowly begin what has so far been a finicky refueling process.
The need for Wednesday’s test is being driven by two previous launch attempts, both of which had to be cleared due to technical issues with the 322-foot rocket, which uses leftover Space Shuttle Program hardware. If all goes well, it could attempt a third launch at 11:37 a.m. EDT Tuesday, Sept. 27.
In late August, it appeared that one of the four RS-25 main engines failed to reach the correct pre-launch temperature, but NASA officials later determined that the poor reading was due to a faulty sensor. During the second attempt earlier this month, a massive leak of liquid hydrogen – one of the SLS’s two propellants with liquid oxygen – forced a scrub after not filling the tank.
Why Artemis flies on hydrogen:Hydrogen is NASA’s fuel of choice for Artemis I, but it’s also harder to manage
Now the teams think that at least part of the second issue was caused by damage to the seal in the hydrogen quick-disconnect, or QD. A NASA official said the “witness mark,” or indentation, was likely caused by foreign object debris in the system and, despite its small size of 0.01 inches, could not be ruled out as a contributor.
“It doesn’t sound like much, but we’re dealing with hydrogen, the smallest particle on the atomic chart,” Mike Sarafin, NASA’s Artemis I mission manager, said during a pre-test briefing on Monday. “So an indentation of that size provides an opportunity for the pressurized gas to leak out.”
Liquid hydrogen is a fine propellant. Not only does it need to be cooled to cooler temperatures than other alternatives such as kerosene or methane, but its small size means it can also be “absorbed” by metals and cause damage. It must be pressed seriously to easily expose flaws or leaks in the loading system.
Artemis I plan to move on
By 3 p.m. EDT on Wednesday, or about 12 hours after the teams clear Pad 39B, NASA expects to conduct a successful propellant loading test. But to get there, officials said some modifications would be made during the countdown and refueling process.
First, the seal was replaced in the hydrogen QD on pad 39B. This would allow for a “kinder, gentler” loading process, designed to pump cooled hydrogen at a slower rate and hopefully avoid thermal shock.
“We are trying to reduce both pressure spikes and thermal spikes,” Jeremy Parsons, deputy manager of ground systems at KSC, said Monday. “What we’re going to do is increase the pressure … so it’s going to be a slow and steady ramp up.”
“Especially with hydrogen, you’re talking very, very extreme temperatures … so really slowly trying to introduce some of those thermal differences and reduce the thermal and pressure shock, ” They said.
Although NASA isn’t sure the level of leak seen during the previous attempt caused damage to the seal, the tests so far, as well as Wednesday’s nearly complete countdown, should provide engineers with answers.
Watch for live coverage of the fueling test floridatoday.com/space EDT starting at 7:30 a.m. Wednesday.
after fuel test
If all goes well with propellant loading, NASA managers will turn their attention to the Space Force, which is responsible for public safety at Kennedy Space Center and neighboring Cape Canaveral Space Force Station.
While all may well be refueling, the Artemis I rocket’s flight termination system, designed to destroy the SLS in the event of an emergency, has passed its expiration date. The batteries powering the system need to be certified by the Space Force every 25 days.
NASA expects the FTS to be extended through a waiver, but will have to wait until after Wednesday’s fuel test to move forward on that. The termination system is not required during the test.
If the fuel test goes well and Space Force exempts, it will pave the way for liftoff during the 70-minute window that opens at 11:37 a.m. EDT Tuesday, Sept. 27. A backup window is available at 2:52 pm on Sunday, October 2.
“The launch criteria for each vehicle are used to develop mission rules that govern acceptable flight behavior to ensure public safety, which is the most important job
Eastern Range,” Space Launch Delta 45 said in a statement. “SLD 45 and Eastern Range enjoy a credible partnership with NASA that dates back to the early days of human spaceflight.”
For the latest, visit floridatoday.com/launchschedule,
Current launch window for Artemis I:
Tuesday, September 27:
- Launch time: 11:37 am EDT
- Launch window: 70 minutes
- Orion Splashdown: November 5
Sunday, October 2:
- Launch time: 2:52 p.m. EDT
- Launch window: 110 minutes
- Orion Splashdown: November 11th
meeting floridatoday.com/space Three hours before each window opens for live video and real-time updates.