NASA conducts Artemis I fueling test at KSC, hydrogen load mostly OK
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NASA teams at Kennedy Space Center completed a lengthy fueling test early Wednesday, giving engineers much-needed data about propellant loading systems and procedures ahead of the next Artemis I launch attempt.
Just before 4 p.m. EDT, NASA confirmed the Space Launch System rocket slated to launch an uncrewed Orion capsule to the moon had been fully fueled with liquid oxygen and hydrogen at pad 39B. The test was deemed necessary after two previous launch attempts in late August and early September were scrubbed due to technical issues, namely with hydrogen-related ground equipment.
"I think the test went really well ... all of the objectives we set out to do, we were able to accomplish," Artemis I Launch Director Charlie Blackwell-Thompson said after the test. "We did not see the same leak signature, which was wonderful and allowed us to go through our loading profile."
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Engineers will review the data and, assuming all is well, prepare for a launch attempt no earlier than 11:37 a.m. EDT Tuesday, Sept. 27. That will mark the opening of a 70-minute window at pad 39B.
"I'm extremely encouraged by the test today ... but I don't want to get ahead of the data," Blackwell-Thompson said. "I'd like the team to have the opportunity to look at it to see if there are changes we need to make."
In the event of another delay, a backup launch opportunity is available at 2:52 p.m. EDT Sunday, Oct. 2. Pulling off this window, however, will be difficult as another NASA mission – three astronauts on one cosmonaut flying on a SpaceX Falcon 9 rocket – is slated to launch from neighboring pad 39A less than 24 hours later at 12:45 p.m. Monday, Oct. 3.
SLS completes fueling test
NASA engineers and officials were optimistic about Wednesday's fueling test, which primarily focused on liquid hydrogen loading equipment at KSC.
After Artemis I's second launch attempt earlier this month was scrubbed due to a significant hydrogen leak, officials said a fueling test rather than a full-on launch attempt would be the best path forward. Loading the 322-foot rocket with oxygen and hydrogen began just after 7:30 a.m. Wednesday morning.
Teams wrapped up the fueling process just before 4 p.m. EDT and later confirmed all test objectives had been met.
Along the way, however, were still some puzzling fluctuations. First, teams noticed the same issue as last time – a leak in a low-level umbilical loading propellant into the rocket – but decided to stop the process and try again. Because hydrogen is supercooled to minus 423 degrees Fahrenheit, ground support equipment is constantly flexing and changing shape.
The stop-and-start, followed by lower pressures to ease the system into more intense loading, appeared to have reseated leaky seals and kept NASA within pre-set margins. Officials before the test had said a "gentler, kinder" fueling process might be one of the keys to avoiding leaks.
Eventually, engineers saw what they wanted: a small hydrogen leak within preset margins that actually grew smaller as pressure was increased. The opposite – small leaks growing as pressure is increased – points to more serious problems as the increase in pressure is supposed to help "seal" connections.
After a few more troubleshooting incidents and checks, NASA reported a fully fueled rocket about an hour later than planned. Had it been launch day, the rocket would have missed the window, but a successful fueling test is still good news and puts Artemis I's progress further than before.
Hydrogen is a historically finicky propellant. It provides the highest performance compared to kerosene and methane, but it needs to be chilled more, meaning more chances for weakening the tanks that hold it. It can also be "absorbed" by metals and cause damage regardless of temperature.
Combined with the high pressure systems needed to pump hydrogen, getting it right can be difficult as even the smallest imperfection can lead to unmanageable leaks.
Assuming engineers are happy with the data and changes to the fueling process, officials will still need to work through two additional issues: getting a specific flight waiver from the Space Force and the busiest period of hurricane season.
Flight termination system
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In order to avoid adding weeks to Artemis I's timeline, NASA opted to build an enclosure around the lower portions of the rocket and work on the hydrogen leaks directly at pad 39B. This allowed SLS to stay on the pad and skip the "several weeks" that would be added had it rolled back to its home in the Vehicle Assembly Building.
But some work can only be done in the VAB.
The flight termination system, designed to destroy the rocket in the event of an emergency, is certified by the Space Force. As the agency responsible for public safety, it must sign off on the system's batteries every 25 days. SLS's current certification expired earlier this month and re-certification work can only be done inside the VAB.
NASA said it would request a waiver to extend the FTS' timeline and avoid another VAB rollback. Now that the fueling test is complete and it appears to have gone well, the Space Force is expected to grant the waiver and extend the system's batteries to nearly double that of the original 25-day certification.
NASA officials are expected to announce the waiver's status Thursday or Friday.
More weather complications
Finally, hurricane season continues to generate even more uncertainty around the mission NASA has been trying to launch since August.
The latest models show Hurricane Fiona, which could have been a threat, moving off toward the Atlantic and away from Florida. But another system known as Invest 98L – which will likely take the name Hermine – is strengthening just north of Venezuela and is projected to approach Florida just before the Sept. 27 Artemis launch window.
Though current projections are likely to change, the latest models put Invest 98L just over Cuba as a Category 1 hurricane by Monday. The SLS countdown includes hundreds of launch constraints including many tied to weather, so even if the storm doesn't get particularly close to Florida, its effects could still force a delay.
After Wednesday's fueling test, NASA said officials are monitoring weather with help from the Space Force and will make a decision on Tuesday's attempt soon.
For the latest, visit floridatoday.com/launchschedule.
Contact Emre Kelly at aekelly@floridatoday.com or 321-242-3715. Follow him on Twitter, Facebook and Instagram at @EmreKelly.
Current launch windows for Artemis I:
Tuesday, Sept. 27:
- Launch time: 11:37 a.m. EDT
- Launch window: 70 minutes
- Orion splashdown: Nov. 5
Sunday, Oct. 2:
- Launch time: 2:52 p.m. EDT
- Launch window: 110 minutes
- Orion splashdown: Nov. 11
Visit floridatoday.com/space three hours before each window opening for live video and real-time updates.
