The mission team fires at the 322-foot (98-meter-high) Artemis I rocket stack, including NASA’s Space Launch System and Orion spacecraft, at the Kennedy Space Center in Florida, albeit with some delays.
The crucial test, known as the wet dress rehearsal, simulates each step of the launch without the rocket actually leaving the launch pad. This includes refueling, reviewing a full countdown, launching simulation, resetting the countdown timer, and emptying the rocket tanks.
The process has been adjusted in response to a problem encountered over the weekend in preparation for this trial.
“Every new rocket that comes out in a new program like this one goes through these updates and understands how the rocket is performing,” Tom Whitmeyer, assistant associate administrator for development systems exploration at NASA headquarters, said during a news conference Monday. “And that’s the kind of thing we’re going through right now.”
The expected time for the two counts to begin is at. 15:57 ET, but that may change due to delays.
A modified test
The problem that the technicians have identified over the weekend is a defective helium check valve. Helium is used to clean the engine before refilling super-cold propellant – the wet in the wet sample – during refueling. Check valves allow gas or liquid to flow in one direction to prevent backflow. In this case, the part that does not work is about 3 inches (7.6 centimeters) long and prevents helium from flowing back out of the rocket.
The valve is difficult to reach while the rocket is on the launch pad, but it can be replaced or repaired after the passage is completed. However, the modified version of the wet test is still required to ensure the safety of the rocket’s flight equipment.
The modified test will remove the load on the valve and the upper rocket stage with minimal propellant operations. Previously, the team had planned full fuel for the core and the upper stages of the rocket, but the valve problem prevents that step from taking place during this test. Assessments will be made to see if further testing is needed.
The rocket and the spacecraft were turned on Wednesday night, and the team held a meeting at. 6 A Thursday to assess the weather and review the status of operations. The team extended a team that was expected to last an hour and a half to two hours after experiencing “a problem with an outage at an off-site supplier of gaseous nitrogen used inside the rocket before refueling,” according to an update from NASA officials . This problem is similar to one that was experienced during a previous experiment on April 4th.
The gaseous nitrogen is used to purify oxygen from the rocket before filling, and it is a safety precaution. The team was able to re-establish the supply of gaseous nitrogen and start burning after 1 p.m. 8 ET.
Refueling begins with cooling liquid oxygen lines to the rocket’s core stage. Thereafter, liquid oxygen and liquid hydrogen fill the core stage through these lines, and they become topped up and refilled as some of the super-cold propellant boils off, according to the agency. The team will also cool propellant lines to the upper stage of the rocket, but not release any propellant due to the existing valve problem.
The Artemis rocket core stage can hold 198,000 gallons (900,126 liters) of liquid oxygen that cools to negative 297 degrees Fahrenheit (negative 182 degrees Celsius). A total of 537,000 liters of propellant will be loaded into the rocket today.
Filling with liquid oxygen was temporarily halted because temperature readings of the propellant showed it was hotter than expected, but the process has now resumed, according to an update from the agency.
Learning valuable lessons
Once this test is completed, the Artemis I rocket will be rolled back into the Vehicle Assembly Building in the space center.
The previous attempts at the wet dress rehearsal have already provided valuable insight, officials said, though the team has worked through various issues.
“We’ve completed many of the test requirements we needed to get out of wet dresses,” Whitmeyer said. “We have a few more that we’ll get to on Thursday. The Mega Moon rocket is in good shape and we’re treating it very carefully.”
Although the exact problems identified during the test trials were not foreseen, it is part of the process when testing a new rocket.
“I can say that these will probably not be the last challenges we will encounter,” Mike Sarafin, Artemis Head of Mission at NASA Headquarters, said during the conference. “But I am convinced that we have the right team in place, and the ability to gather around these issues and overcome them is something we are proud of.”
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.
Current launch options include June 6 to June 16, June 29 to July 17 and July 26 to August 9, Sarafin said.