To recap what happened on Saturday, Sept. 3: Launch managers confidently entered this weekend’s effort to launch the rocket, called the Space Launch System, or SLS. But then, as the rocket was once again loaded with supercooled liquid hydrogen propellant, it developed a major leak. And NASA said Tuesday it will begin attempting to fix those issues while the rocket is still on the launch pad. But ultimately, the space agency will still have to drop the rocket back to the nearby Vehicle Assembly Building, a 4.2-mile journey that takes about 10 hours, in order to “recharge the system’s batteries,” according to a blog post by the space agency. NASA on Tuesday. And when it comes to setting a new release date, the timing will be complicated.
Timing can be everything
On a given day, there are specific times — or “launch windows” — when the rocket is allowed to launch, and they can range from about half an hour to a few hours a day. But even these windows are not available every day. There are also “launch periods,” which are periods of days when the moon aligns with Earth in a way that is favorable for this mission. The last launch period ended on Tuesday, September 6, and NASA had said there was no way the SLS would be ready to fly during that period. The next launch period runs from September 19th to October 4th. But there’s another potential issue: NASA plans to launch its Crew-5 mission, which will carry a new crew of astronauts to the International Space Station on a SpaceX rocket, on Oct. 3. And NASA will have to work to ensure that one launch will not collide with another. Later in October, another launch period will begin, from October 17th to October 31st. This period will offer up to 11 possible launch windows for the SLS. (Note: no release times available on October 24, 25, 26 and 28.) Exactly what period and window of NASA’s goals will depend on several factors, including how well it can coordinate with SpaceX on the Crew-5 launch and how long the SLS rocket remains on the launch pad as engineers work to the leakage problem, according to Jim Free, NASA’s associate administrator for exploration systems development.
Super cool fuel
When the SLS rocket is fueled, it requires massive amounts of supercooled liquid oxygen and liquid hydrogen to be pumped into the rocket’s tanks. When loading the hydrogen, the fuel starts pumping slowly, but then increases its speed in what is called a “rapid fill”. And during that quick fill there was a “big leak” — even bigger than the leaks NASA found during the Aug. 29 launch attempt. That’s why startup managers want to make sure they’ve identified a fix and the root of the problem before making the next attempt. As of Saturday, one speculation was that a problem with a valve may have caused the hydrogen to overpressurize, putting it under 60 pounds per square inch of pressure instead of the 20 pounds per square inch they had hoped for, Michael Sarafin, Artemis Mission Director, said the Saturday. By Saturday, NASA had also tried to address various problems encountered during the first launch attempt of the SLS rocket on August 29. He addressed some leaks that occurred during refueling and assessed the risks of a problem with an engine cooling system and a crack in some foam covering one of the rocket’s tanks. NASA may choose to take another look at these issues as it works toward its next launch attempt. Further complicating the selection of the next target launch date is the precarious weather in Florida. For any rocket launch, rough winds, lightning or other adverse conditions can cause more delays. Late summer and early fall can also bring hurricanes to the Florida coast where SLS is located. NASA is working on the possibilities, and the public can expect more answers in the coming days and weeks.
This is rocket science
As NASA officials have said in the past, they hope to convey that these delays and technical issues do not necessarily indicate a major problem with the rocket. Before SLS, NASA’s Space Shuttle program, which had been flying for 20 years, could withstand frequent launches. SpaceX’s Falcon rockets also have a history of being cleaned up for mechanical or technical issues. This is, after all, rocket science. “I can tell you that these teams know exactly what they’re doing and I’m very proud of them,” NASA Administrator Bill Nelson said Saturday. “We’ve tried to emphasize that this is a test and that a test has a certain risk, and we’ve hammered that into every public comment we’ve had, in order to align expectations with reality.” Eleftheros, the NASA associate administrator, added that his team will always make a launch attempt optimistic that liftoff will happen. “I’m sure the question will be asked, ‘Are we confident?’” he said. “I really like that question because it’s like (asking), ‘Are you sure you’re going to get out of bed this morning?’ This mission, called Artemis I, is expected to pave the way for many other missions to the moon. The Artemis II mission, planned for next year, is expected to follow a similar flight path around the Moon, but will have a crew. And later this decade, Artemis III is expected to land astronauts on the lunar surface for the first time since NASA’s Apollo program in the mid-20th century. CNN’s Ashley Strickland contributed to this story.
