The agency’s next opportunity to begin firing the 322-foot (98-meter-high) Artemis I rocket stack, including NASA’s Space Launch System and the Orion spacecraft, is on Monday.
“We’ve fixed it, and we’ve reconfigured where we were earlier today,” Charlie Blackwell-Thompson, Artemis’ launch director, told a news conference Sunday. “Our team has met and laid out our plan for how we’ll get back to refueling tomorrow, so it’s all done.”
The team is still troubleshooting the fan problem and hopes to reach a solution tonight. If it goes according to plan, they will resume refueling the rocket at 7 ET on Monday and begin the countdown around 14:40 ET.
The test, known as the wet dress rehearsal, began Friday afternoon at 7 p.m. 17 ET.
The wet dress rehearsal simulates each step of the launch without the rocket actually leaving the launch pad. This includes igniting the SLS rocket and Orion spacecraft, loading super-cold propellant into the rocket’s tanks, reviewing a full countdown simulating launch, resetting the countdown timer, and draining the rocket tanks.
Operations were halted Sunday before propellants were loaded into the rocket’s core stage “due to loss of ability to put pressure on the mobile launch pad,” according to an update shared by the agency.
Prime and redundant supply fans for the mobile launcher did not work properly, and each encountered different issues, Blackwell-Thompson said.
“The blowers are necessary to give positive pressure to the enclosed areas within the mobile launch pad and keep out dangerous gases. Technicians are not able to safely continue to load the propellants into the rocket’s core stages and temporary cryogenic propulsion stages without this capability.”
The fans ensure that gases do not build up and cause a fire hazard or an increase in hazards, Blackwell-Thompson said.
Prior to this issue on Sunday afternoon, Artemis I managed a heavy thunderstorm in the Kennedy Space Center on Saturday.
Four lightning strikes hit the lightning towers within the perimeter of Launchpad 39B. While the first three were low-intensity strikes to tower two, the fourth strike was much more intense and hit tower one.
When these attacks took place, the Orion spacecraft and the SLS rocket core stage were turned on. The rocket’s temporary cryogenic propulsion stages and boosters were not.
The fourth attack was quite rare because it was a positively charged cloud-to-ground attack and far more powerful than the others, according to NASA weather experts.
Each of the towers is topped with a fiberglass mast and a series of overhead or overhead lines, wires and conductors that help divert lightning strikes away from the rocket, Parsons explained. This new system provided more shielding than that used during the Shuttle program. It also has a number of sensors that can determine the condition of the rocket after lightning strikes, preventing days of delays caused when teams have to assess the rocket.
“We do not think the (fan problem) was related to the storm or the lightning event,” Blackwell-Thompson said. “It continued to run normally during the storm activities. And then it ran this morning for several hours before encountering a problem.”
Despite strikes and delays, the team was ready to continue with the wet dress rehearsal on Sunday until they encountered the idea.
Parsons shared a reminder that this is the point of the wet dress rehearsal – figuring out cracks in a new system before launch day.
“One good thing about knowing this is a test, and not launching today, is that we have the flexibility of the test window to work through first-time problems,” Parsons tweeted.
“We have a lot of new experiences as we set up for the Artemis I mission in particular,” Mike Sarafin, Artemis Head of Mission, said during the news conference. “And one of the new experiences was literally seeing a 32-story rocket sitting out there and getting a lightning strike around it with this lightning protection system. It did a perfect job of protecting the vehicle.”
“The team is prepared for this, we just need to get through a few technical issues,” Sarafin added. “They have shown incredible discipline and toughness and I am sure we will get there soon.”
The results of the wet dress rehearsal will determine when the unmanned Artemis I will launch on a mission that goes beyond the moon and returns to Earth. This mission will launch NASA’s Artemis program, which is expected to return humans to the moon and land the first woman and first colored person on the moon’s surface in 2025.
What to expect next
When the wet general rehearsal resumes, it will involve loading the rocket with more than 700,000 gallons (3.2 million liters) of super-cold propellant – the “wet” in the wet general exam – and then the team will go through all the steps against firing.
“Some venting can be seen during refueling,” according to the agency, but it’s about it for visible action at the launch pad.
Team members count down to within one minute and 30 seconds before launch and pause to ensure they can hold launch for three minutes, resume and let the clock run down to 33 seconds, and then pause the countdown.
Then they will reset the clock to 10 minutes before launch, go through the countdown again and finish at 9.3 seconds, just before ignition and launch would take place. This simulates what is called scrubbing a launch or interrupting a launch attempt if the weather or technical problems would prevent a safe launch.
At the end of the test, the team will drain the rocket’s propellant, just as it would during a real scrub.
Depending on the outcome of the wet dress rehearsal, the unmanned mission may begin in June or July.
During the flight, the unmanned Orion spacecraft will launch on top of the SLS rocket to reach the moon and travel thousands of miles beyond it – longer than any spacecraft designed to transport humans has ever traveled. This mission is expected to last for a few weeks and will end with Orion splashing down into the Pacific Ocean.
Artemis I will be the last test site for Orion before the spacecraft transports astronauts to the moon, 1,000 times farther from Earth than where the International Space Station is located.
After the unmanned Artemis I flight, Artemis II will be a manned bypass of the moon, and Artemis III will return astronauts to the moon’s surface. The timeline for subsequent mission launches depends on the results of the Artemis I mission.