Monday (June 20) was a big day for NASA’s Artemis 1 mission.
The agency’s huge new moon rocket, the Space launch system (SLS), completed a more than 50-hour launch simulation known as the “wet dress rehearsal” on Monday evening (June 20). After several failed attempts in April, members of the mission team were able to do so SLS fully powered for the first time Monday, ending a series of crucial pre-launch tests.
It was a great milestone for the Artemis 1 mission to the moon, but there were some downsides along the way.
Related: NASA’s Artemis 1 moon mission is explained in the photos
NASA’s Kennedy Space Center (KSC) ground crews in Florida spent the weekend reviewing procedures and checklists for the SLS, Orion capsule, and Artemis 1 ground systems in the same way. that they would if they were preparing for a real launch.
SLS is the backbone of NASA Artemis programa follow-up to the new Apollo era that the space agency hopes will help establish a permanent human presence in the moon. And with a new moon comes a new moon rocket. SLS has never flown, and the recent wet dress rehearsal was supposed to be its last hurdle. But it is still unclear whether or not the Artemis 1 is ready to fly now.
Monday’s activities focused primarily on filling the rocket’s cryogenic fuel tanks. Two-stage SLS uses liquid hydrogen (LH2) and liquid oxygen (LOX) as hypergolic propellants. Three attempts to power the rocket during a previous wet clothing attempt in April were exhausted when operators has encountered technical issuesincluding a high hydrogen leak in the mobile launch pad (MLP) of the Artemis 1 battery.
These issues were addressed at the KSC Vehicle Assembly Building (VAB) over the past month, but on Monday drivers encountered another hydrogen leak while wearing the wet suit on the launch pad. This new leak, however, appeared in a “quick disconnect,” a point where the power cords connecting the SLS to the MLP are designed to separate during release.
This new leak affected the procedure on Monday. The technicians’ efforts to solve the problem were unsuccessful and their work pushed the count back three hours. But with the SLS completely shut down, NASA officials made the decision to forward a software patch that would allow them to continue with the simulated countdown anyway.
The patch allowed the ground sequencer to jump basically over the automatic checks that would have detected the leak, but the on-board flight systems for SLS could not experience the same secure bypass. As expected, the terminal count proceeded to the second mark of the T-33, at which point the terrestrial computers handed over flight control to the SLS systems.
The count finally stopped at T-29 seconds. NASA hoped to run the clock up to T-9 seconds, as originally planned, but they believe the wet suit test was largely a success, regardless.
Photos: New mega-rocket from NASA’s space launch system
“I’d say we’re in the 90th percentile,” Mike Sarafin, manager of the Artemis mission at NASA, said during a call with reporters on Tuesday (June 21st).
“Terminal counting is a very dynamic time,” said Charlie Blackwell-Thompson, Artemis’ launch director for KSC’s Exploration Ground Systems program.
There are “many time-critical events happening in terminal counting, which are checked in both flight and ground software, and in the interaction between the two,” he added.
Citing the quick disconnect leak as the only major hiccup during Monday’s tank, Blackwell-Thompson and other NASA officials in the call agreed that the wet suit was “extremely soft.”
Now, agency officials need to determine if this wet suit was good enough. The leak prevented the count from reaching the second T-9 target for the wet suit launch abortion, but that doesn’t mean NASA has to retry the wet suit before deciding to launch the mission. Artemis 1, who will send an unmanned Orion on a voyage of about a month around the Moon. And nothing was decided on Tuesday’s call.
“There are a couple of things we didn’t get in the terminal count,” Blackwell-Thompson said. “Let’s see what they are. We’ll see what that means to us, if there are ways to test them, and then we’ll come back and make a recommendation.”
“We really have to sit down and … look at what we’ve achieved, see what extra work might be required and take a look at the [quick disconnect]Sarafin added during Tuesday’s call, noting that since the long day of NASA operators on Monday, not much work had been done to analyze any of the test data.
NASA officials at the call were optimistic about the way forward, although they were not committed to what will be next for Artemis 1 in the immediate future. At the call, there was a shared confidence that a clearer path would come out in a few days, after the team had a chance to examine the Artemis 1 stack and wet suit data.
“We’ll take all the data from yesterday and incorporate it the next time we load this vehicle,” Blackwell-Thompson said. “I’m sure it will be as smooth as the basic stage was yesterday.”
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