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On April 10, NASA announced on Saturday that it would postpone the key test of the launch vehicle for the first mission of the Artemis return to the moon program for another two days, which is currently scheduled for April 12 < p > < / P > < p > NASA's first mission to return to the moon is called Artemis 1. The agency originally planned to conduct "wet dress rehearsal (WDR) for the space launch system (SLS) rocket performing this mission at launch pad 39B of the Kennedy Space Center (KSC) on April 9 local time (Beijing time), that is, simulate each important step before propellant filling and other launch < p > NASA posted a blog post saying that the reason why it decided to postpone the test again was that there was a problem with the "helium check valve" of the ground refueling system. "Engineers found that a helium check valve did not work as expected, and program changes were needed to ensure the safety of flight hardware. Engineers will evaluate the valve and replace it if necessary," the agency said < p > NASA officials explained in the update that helium is used to clean engine pipelines before filling and discharging propellant, and the "helium check valve" can prevent helium from leaking from the SLS rocket < p > NASA officials said that the revised WDR will mainly focus on the propellant filling test of the SLS core stage and the minimum propellant filling operation with the Kennedy Space Center ground system during the temporary cryogenic propulsion phase (ICPs). "Due to changes in the propellant filling procedures required for the revised test, WDR will resume on April 12," they added < p > this is not the first time that the Artemis 1 WDR test has been postponed. The test was originally scheduled for February, but was postponed due to the need to cooperate with other tests, followed by propellant filling problems. The latest test was scheduled to start on April 1 and end 48 hours later (i.e. April 3). However, several problems occurred during the test, including the failure of SLS's huge mobile launch tower fan system and the jamming of pressure relief valve, which led to the suspension of the test < p > subsequently, NASA agreed to make way for the ready SpaceX's first purely commercial manned mission AX-1 launch, prompting the whole test to be postponed again. The AX-1 team lifted off from Launch Pad 39A at Kennedy Space Center on April 8, clearing the way for Artemis 1 to resume WDR testing. This test is critical to determining when NASA will perform the Artemis I mission < p > in the Artemis 1 mission, NASA will launch an unmanned Orion spacecraft through SLS rocket to carry out a lunar orbiting mission for about one month. NASA will not set a target launch date until the WDR test is completed and the team analyzes the result data, but the mission is unlikely to launch before June < p > if the Artemis 1 mission goes well, Artemis 2 will launch astronauts for a manned flight around the moon in 2024, and Artemis 3 will land near the south pole of the moon in 2025 or 2026. (small) < / P > < p >

2023-03-22 10:04:52