The critical test, known as the wet dress rehearsal, simulates each launch step without the rocket actually leaving the launch site. This includes loading the propellant, performing a full launch simulation countdown, resetting the countdown clock, and draining the rocket tanks. The process has been adapted in response to a problem encountered over the weekend in preparation for this effort. “Any new rocket that appears in a new program as it goes through these updates and understands the rocket’s performance,” said Tom Whitmeyer, a deputy research fellow at NASA headquarters, during a news conference. Monday. “And that’s the kind of thing we’re going through right now.” The expected time for the two countdowns to begin is 3:57 p.m. ET, but that may change due to delays.

A modified test

The problem the engineers identified over the weekend is a malfunctioning solar check valve. The sun is used to clean the engine before loading the supercooled propellant – the rehearsal wet in a wet dress – when refueling. Non-return valves allow gas or liquid to flow in one direction to prevent reverse flow. In this case, the non-functioning part is about 3 inches (7.6 cm) long and prevents the sun from flowing behind the rocket. The valve is difficult to reach while the rocket is on the launch surface, but can be replaced or repaired once the passage is complete. However, the modified version of the wet dress rehearsal is still necessary to ensure the safety of the rocket flight material.
The modified test will remove the stress of the valve and the upper rocket stage with minimal propulsion functions. Previously, the team had planned to fully supply the core and the upper stages of the rocket, but the valve problem prevents this step from taking place during this test. Evaluations will be made to determine if further tests are needed. The rocket and spacecraft were powered on Wednesday night and the team held a meeting at 6 p.m. ET Thursday to assess the weather and monitor the state of the business. The team extended the wait, which was expected to last an hour and a half to two hours, after encountering “a problem with a shutdown of an off-site nitrogen gas vendor used inside the rocket before the propellant was loaded,” according to a statement. by NASA executives. This issue is similar to what was addressed during a previous attempt on 4 April. Nitrogen gas is used to remove oxygen from the rocket before refueling and is a safety measure. The team was able to restore the nitrogen gas supply and start refueling after 8 p.m. ET. The supply starts with cooling of the liquid oxygen lines for the rocket core stage. Liquid oxygen and liquid hydrogen then fill the nucleus stage through these lines, completing and replenishing as some of the supercooled propellant boils, according to the body. The team will cool the propulsion lines for the upper tier of the rocket as well, but will not release any propellants due to the existing valve problem. The core stage of the Artemis rocket can hold 198,000 gallons (900,126 liters) of liquid oxygen cooled to negative 297 degrees Fahrenheit (negative 182 degrees Celsius). A total of 537,000 gallons of propulsion will be loaded on the rocket today. Loading of liquid oxygen was temporarily stopped because the propellant temperature measurements showed that it was hotter than expected, but the process is now back, according to an update from the body.

Learning valuable lessons

Once this test is complete, the Artemis I rocket will be transported back to the Vehicle Assembly Building in the space center. Previous attempts at the wet dress rehearsal have already provided valuable information, officials said, although the team has worked on a number of issues. “We have completed many of the test requirements we needed to get out of the wet dressing business,” Whitmeyer said. “We have a few more to reach on Thursday. The mega moon rocket is in excellent condition and we are dealing with it very carefully.” Although the exact issues identified during the test were not expected, they are part of the process of testing a new missile. “I can say that these are probably not the last challenges we will face,” said Mike Sarafin, director of the Artemis mission at NASA headquarters, during the conference. “But I’m sure we have the right team in place and the ability to rally around these problems and overcome them is something we are proud of.” The results of the wet dress rehearsal will determine when the unpaid Artemis A will be launched on a mission that transcends 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 the first colored person on the lunar surface by 2025. Current launch window features include June 6 to June 16, June 29 to July 17 and July 26 to August 9, Sarafin said.