The mission team was trying to supply the 322-foot (98 m) Artemis I rocket stack, including NASA’s Space Launch System and the Orion spacecraft, at the Kennedy Space Center in Florida, but encountered a number of delays.
According to a tweet from Jeremy Parsons, deputy director of the Exploration Ground Systems program at the Kennedy Space Center, “the team will not conduct final countdown activities today as planned, and will evaluate next steps after today’s operations.”
The agency said the missile remains stable and in a safe configuration.
The critical test, known as the wetsuit exercise, simulates each stage of a launch without the missile actually emerging from the launch pad. This includes loading fuel, performing a full launch simulation countdown, resetting the countdown clock, and draining the missile tanks.
The process was previously modified in response to an issue encountered over the weekend during preparations for this attempt.
“Any new missile that’s introduced into a new program like this type of missile goes through these updates and understands how the missile performs,” Tom Whitmaier, deputy associate administrator for exploration systems development at NASA Headquarters, said during a briefing Monday. “And that’s the kind of thing we’re going through right now.”
rate test
The problem that engineers identified over the weekend is a malfunctioning helium check valve. Helium is used to purge the engine before loading the supercooled fuel – which is wet during wet training – during refueling. Check valves allow gas or liquid to flow in one direction to prevent reverse flow. In this case, the non-working portion is about 3 inches (7.6 cm) long and prevents helium from flowing back from the rocket.
The valve is difficult to reach while the missile is sitting on the launch plate, but it can be replaced or repaired after the operation is complete. However, the modified version of wet training is still necessary to ensure the safety of the missile’s flight equipment.
The revised test will depressurize the valve and upper rocket stage with minimal thrust. Previously, the team had planned to fully refuel the rocket’s primary and upper stages, but a valve problem prevented this step from occurring during this test. Evaluations will be done to see if more tests are needed.
The rocket and spacecraft were operational Wednesday night, and the team held a meeting at 6 a.m. ET Thursday to assess the weather and review the state of operations. The team extended the waiting period, which was expected to last from one and a half hours to two hours, after experiencing “a problem with an outage at an off-site vendor of gaseous nitrogen used inside the rocket prior to loading the fuel,” according to an update. From NASA officials. This issue is similar to the one that occurred during a previous attempt on April 4th.
Gaseous nitrogen is used to purge the rocket of oxygen before refueling it, a safety measure. The team was able to re-establish the gaseous nitrogen supply and begin refueling after 8 a.m. ET.
Refueling begins with cooling the liquid oxygen lines of the rocket’s primary stage. Then, liquid oxygen and liquid hydrogen fill the base phase through these lines, topping up and regenerate as some of the supercooled fuel boils, according to the agency. The team will also cool the fuel lines for the rocket’s upper stage, but will not release any propellant due to the existing valve problem.
The Artemis rocket’s core stage can hold 198,000 gallons (900,126 liters) of liquid oxygen that is cooled to minus 297 degrees Fahrenheit (minus 182 degrees Celsius). A total of 537,000 gallons of propellant will be loaded into the rocket when the primary stage is fully refueled.
“Hydrogen is extremely dangerous, cold, and a small molecule known to leak. All of these systems have been shut down, leak-checked and tested as much as possible prior to rehearsing in wet clothes,” according to a tweet from Jeremy Parsons, deputy director of the Exploration Ground Systems Program at Kennedy Space Center.
“Given the unique operating conditions with the missile, we are prepared and know that leaks are a realistic possibility. We have amazing systems to detect dangerous gases and leaks that keep the missile safe and alert us to conditions outside normal standards.”
The team will continue cooling hydrogen lines connected to the upper stage of the rocket to collect more data, and there are no plans to load liquid hydrogen or liquid oxygen into the upper stage tanks.
The liquid hydrogen tank in the primary stage will remain about 5% full, and liquid oxygen will no longer be loaded.
Learn valuable lessons
Once this test is complete, the Artemis I rocket will be returned to the Space Center’s Vehicle Assembly Building.
Officials said previous attempts at rehearsal have already provided valuable information, even as the team has worked through many issues.
“We completed a lot of testing requirements that we needed to get rid of wet clothes activity,” Whitmer said. “We have a few more that we’ll get to on Thursday. The massive moon rocket is in good condition and we are treating it very carefully.”
Although the exact problems identified during the test attempts were not foreseen, they are part of the process when testing a new missile.
“I can say that these probably won’t be the last challenges we’ll face,” Mike Sarafin, Artemis mission manager at NASA Headquarters, said during the conference. “But I am confident that we have the right team in place and the ability to come around and overcome these problems is something we can be proud of.”
The results of training in wet clothes will determine when Artemis I will embark on a mission beyond the Moon and back 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 people of color on the moon by 2025.
Sarafin said the current launch window includes June 6 through June 16, June 29 through July 17, and July 26 through August 9.