NASA teams investigating cushion instruments at Kennedy Space Center have found a possible cause behind the hydrogen line leak that canceled the Artemis I Moon mission’s latest attempt, clearing the way for a refueling test this week.
Managers and engineers have already begun preparing for their arrival at the Launch Control Center starting Monday evening, a process that will continue through what is essentially a dummy countdown similar to launch day. At 3:40 a.m. EDT on Wednesday, September 21, teams will remove the SLS 39B rocket platform and slowly begin what has hitherto been a difficult refueling operation.
The necessity of Wednesday’s test was prompted by two previous launch attempts, both of which had to be removed due to technical problems with the 322-foot rocket, which uses the hardware of the remaining Space Shuttle program. If all goes well, it could lead to a third launch attempt at 11:37AM ET Tuesday, September 27.
In late August, it emerged that one of the RS-25’s four main engines had failed to reach the correct temperature prior to launch, but NASA officials later determined that the poor reading was due to a faulty sensor. During a second attempt earlier this month, a large liquid hydrogen leak — one of two SLS fuels along with liquid oxygen — caused a rubbing action after the tank could not be filled.
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The teams now believe that at least part of the second problem was caused by seal damage in rapid hydrogen separation, or QD. A NASA official said the “witness mark,” or indentation, was most likely caused by foreign body debris in the system, and despite its small size at 0.01 inches, cannot be ruled out as a contributor.
“It doesn’t look like much, but we’re dealing with hydrogen, the smallest particle on the atomic diagram,” Mike Sarafin, NASA’s Artemis I mission manager, said during a pre-test briefing on Monday. “So an indentation of this size provides an opportunity for pressurized gas to leak through.”
Liquid hydrogen is a difficult propellant. Not only does it need to be cooled to cooler temperatures than other options like kerosene or methane, but its small size means it can even be “absorbed” by metals and cause damage. It must also be seriously compressed, making it easier to detect defects or leaks in the loading system.
Artemis plans to move forward
By 3 p.m. EDT on Wednesday, or about 12 hours after the teams removed the 39B, NASA hopes to conduct a successful fuel loading test. But in order to get there, officials said some adjustments will be made during the countdown and refueling operations.
First, the seals in the QD for hydrogen were replaced in the 39B pad. This will allow for a “gentler” loading process designed to pump out cooled hydrogen at slower rates and hopefully avoid thermal shocks.
“We are trying to reduce both pressure elevations and thermal elevations,” Jeremy Parsons, deputy director of ground systems at KSC, said Monday. “What we will do is increase the pressure … so it will be a slow and steady slope.”
“For hydrogen in particular, you’re talking about very extreme temperatures … so you’re really trying to slowly introduce some of those thermal differences and reduce the thermal shocks and pressure,” he said.
Although NASA isn’t sure if damage to the seal caused the level of leak seen during the last attempt, the tests so far plus a nearly complete countdown to Wednesday should provide the answers engineers need.
For live coverage of the refueling test, visit floridatoday.com/space Starting at 7:30 a.m. EDT Wednesday.
After the refueling test
If all goes well with the propellant loading, NASA administrators will turn their attention to the Space Force, which is responsible for public safety at the Kennedy Space Center and the nearby Cape Canaveral Space Station.
Although all may well be, the Artemis I missile flight termination system designed to destroy the SLS in an emergency situation has passed its expiration date. The batteries that power the system need to be approved by Space Force every 25 days.
NASA is hoping to extend the FTS via the waiver, but will wait until after Wednesday’s refueling test to move forward with it. There is no need for system termination during testing.
If the refueling test goes well and the Space Force grants the waiver, it will clear the way for liftoff during a 70-minute window that opens at 11:37 a.m. EDT Tuesday, Sept. 27. A backup window is available at 2:52 p.m. Sunday, October 2.
“The launch criteria for each vehicle are used to develop mission rules that govern permissible flight behavior to ensure public safety, the first mission in the world
East Range said, “Space Launch Delta 45 in a statement.” SLD 45 and Eastern Range have enjoyed a trusted partnership with NASA going back to the early days of human spaceflight.
For the latest, visit floridatoday.com/launchschedule.
Artemis I current operating windows:
Tuesday 27 September:
- Release time: 11:37 AM EST
- Launch window: 70 minutes
- Orion Splashdown: November 5
Sunday 2 October:
- Release time: 2:52 PM EST
- Launch window: 110 minutes
- Orion Splashdown: November 11
visit floridatoday.com/space Three hours before each window opens for live video and real-time updates.
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